High porosity macroporous monolithic substrates

Abstract

A monolithic substrate including a matrix of a glass-ceramic composite material defining a continuous interconnected pore structure. The glass-ceramic composite material has a porosity of at least 48% by volume as determined by mercury intrusion porosimetry. At least 20% of the porosity is contributed by pores having a pore diameter between 0.1 μm and 1 μm, as determined by mercury intrusion porosimetry.

Description

HIGH POROSITY MACROPOROUS MONOLITHIC SUBSTRATES Cross-reference to Related Applications

[0001] This application claims the benefit of priority under 35 U.S.C. §119 of U.S. Provisional Application Serial No. 63 / 604,603, filed on November 30, 2023, the content of which is relied upon and incorporated herein by reference in its entirety.BACKGROUND

[0002] One method of removing CO2 from a gas, either from a point source or from ambient air includes flowing a CO2 laden stream through a monolith containing a sorbent that adsorbs the CO2. The CO2 can later be desorbed for removal (e.g., via heating of the monolith). Similarly, exhaust emissions or other fluid streams, can undergo pollution abatement or otherwise be treated by flowing the fluid stream through a catalyst-coated monolith.

[0003] To coat conventional substrates with a functional material such as a catalyst or sorbent, a high surface area material may be applied to the substrate in the form of a slurry which is later dried and calcined to form a ceramic washcoat. A common example of such a high surface area material is gamma alumina. A catalyst or sorbent material can be applied (coated) along with or onto the high surface area material in order to enable the coated substrate to treat exhaust emissions, capture CO2, or serve another purpose or function.SUMMARY OF THE INVENTION

[0004] In various aspects, the present disclosure provides a monolithic substrate. The monolithic substrate comprising a matrix of a glass-ceramic composite material defining a continuous interconnected pore structure, wherein the glass-ceramic composite material has a porosity of at least 48% by volume as determined by mercury intrusion porosimetry, and wherein at least 20% of the porosity is contributed by pores having a pore diameter between 0. 1 pm and 1 pm, as determined by mercury intrusion porosimetry.

[0005] In various aspects, at most 5% of the porosity, by volume, is contributed by pores having a pore diameter less than 0.1 pm, as determined by mercury intrusion porosimetry.

[0006] In various aspects, at most 3% of the porosity, by volume, is contributed by pores having a pore diameter less than 0.1 pm, as determined by mercury intrusion porosimetry.

[0007] In various aspects, at most 1% of the porosity, by volume, is contributed by pores having a pore diameter less than 0.1 pm, as determined by mercury intrusion porosimetry.

[0008] In various aspects, at most 5% of the porosity, by volume, is contributed by pores having a pore diameter less than 0.05 pm, as determined by mercury intrusion porosimetry.

[0009] In various aspects, a median pore size of the interconnected pore structure is between 0.1 pm and 1 pm, as determined by mercury intrusion porosimetry.

[0010] In various aspects, a median pore size of the interconnected pore structure is less than 1 pm, as determined by mercury intrusion porosimetry.

[0011] In various aspects, a median pore size of the interconnected pore structure is less than 1 pm, as determined by mercury intrusion porosimetry.

[0012] In various aspects, the porosity is at least 50% by volume, as determined by mercury intrusion porosimetry.

[0013] In various aspects, the porosity is at least 50% by volume, as determined by mercury intrusion porosimetry.

[0014] In various aspects, the porosity is at least 55% by volume, as determined by mercury intrusion porosimetry.

[0015] In various aspects, the porosity is at least 48% to 75% by volume, as determined by mercury intrusion porosimetry.

[0016] In various aspects, the porosity is at least 50% to 75% by volume, as determined by mercury intrusion porosimetry.

[0017] In various aspects, the interconnected pore structure has a multimodal pore size distribution.

[0018] In various aspects, the multimodal pore size distribution is comprises a first differential intrusion peak at a first pore diameter between 0. 1 pm and 1 pm and a second differential intrusion peak at a second pore diameter between 1.5 pm and 30 pm.

[0019] In various aspects, the second differential intrusion peak is at a pore diameter of at least 5 pm.

[0020] In various aspects, at least 50% of the porosity is contributed by pores having a pore diameter between 0. 1 pm and 1 pm, as determined by mercury intrusion porosimetry.

[0021] In various aspects, at least 80% of the porosity is contributed by pores having a pore diameter between 0. 1 pm and 1 pm, as determined by mercury intrusion porosimetry.

[0022] In various aspects, the interconnected pore structure has a monomodal pore size distribution with a single differential intrusion peak.

[0023] In various aspects, the glass-ceramic composite material comprises at least 50 wt% amorphous silica.

[0024] In various aspects, the glass-ceramic composite material comprises at least 70 wt% amorphous silica.

[0025] In various aspects, the glass-ceramic composite material comprises at least 90 wt% amorphous silica.

[0026] In various aspects, the glass-ceramic composite material comprises at least 50% sintered diatomaceous particles.

[0027] In various aspects, the glass-ceramic composite material comprises at least 70 wt% sintered diatomaceous earth particles.

[0028] In various aspects, the glass-ceramic composite material comprises at least 90 wt% sintered diatomaceous earth particles.

[0029] In various aspects, the glass-ceramic composite material comprises at least 5 wt% sintered fused silica particles.

[0030] In various aspects, the glass-ceramic composite material comprises at least 10 wt% sintered fused silica particles.

[0031] In various aspects, the glass-ceramic composite material comprises at least 15 wt% sintered fused silica particles.

[0032] In various aspects, the glass-ceramic composite material comprises at least 5% sintered aluminosilicate particles.

[0033] In various aspects, the glass-ceramic composite material comprises at least 10% sintered aluminosilicate particles.

[0034] In various aspects, the glass-ceramic composite material comprises at least 5% sintered clay mineral particles.

[0035] In various aspects, the glass-ceramic composite material comprises at least 10% sintered clay mineral particles.

[0036] In various aspects, the monolithic substrate has a honeycomb configuration comprising an array of intersecting walls defining channels extending axially through the monolithic substrate.

[0037] In various aspects, a bulk density of the monolithic substrate is at most 1.1 g / cm3.

[0038] In various aspects, a bulk density of the monolithic substrate is at most 1.05

[0039] In various aspects, a bulk density of the monolithic substrate is at most 1 g / cm3.

[0040] In various aspects, a bulk density of the monolithic substrate is from 0.6 g / cm3 to 1.1 g / cm3.

[0041] In various aspects, an apparent density of the glass-ceramic composite material is at most 2.5 g / cm3.BRIEF DESCRIPTION OF THE FIGURES

[0042] The drawings illustrate generally, by way of example, but not by way of limitation, various aspects of the present disclosure.

[0043] FIG. 1 illustrates a representative honeycomb body comprising a matrix or array of intersecting walls that define channels extending axial therethrough, in accordance with aspects of the disclosure herein.

[0044] FIG. 2 illustrates a SEM micrograph of a polished section of a glass and / or ceramic material formed from a composition including talc, a sintering aid, and cross-linked pea starch, in accordance with various aspects.

[0045] FIG. 3A illustrates cumulative intrusion versus pore size diameter of the material shown in FIG. 2 as measured during mercury porosimetry testing, in accordance with various aspects.

[0046] FIG. 3B illustrates differential intrusion versus pore size diameter of the material shown in FIG. 2 as measured during mercury porosimetry testing, in accordance with various aspects.

[0047] FIG. 4A illustrates a SEM micrograph of diatomaceous earth particles, in accordance with various aspects.

[0048] FIG. 4B illustrates a SEM micrograph of diatomaceous earth particles, in accordance with various aspects.

[0049] FIG. 5A-B illustrate SEM micrographs of a polished cross section of a composition including diatomaceous earth, talc, sintering aid, and cross-linked pea starch after firing, in accordance with various aspects.

[0050] FIG. 6A-C illustrate differential intrusion versus pore size distribution as measured during mercury porosimetry testing for fired ceramic matrices including various proportions of diatomaceous earth and cross-linked pea starch, in accordance with various aspects.

[0051] FIGS. 7A-B illustrate differential intrusion versus pore size distribution as measured during mercury porosimetry testing for fired ceramic matrices including various types of diatomaceous earth with cross-linked pea starch, in accordance with various aspects.

[0052] FIG. 8A illustrates cumulative intrusion versus pore size diameter of a substrate having a trimodal pore size distribution as measured during mercury porosimetry testing, in accordance with various aspects.

[0053] FIG. 8B illustrates differential intrusion versus pore size diameter of a substrate having a trimodal pore size distribution as measured during mercury porosimetry testing, in accordance with various aspects.

[0054] FIGS. 9A and 9B are SEM micrographs at two different magnifications of the polished cross-section of a monolithic substrate formed in accordance with Example 42 disclosed in Table 9 herein.

[0055] FIGS. 10A and 10B are SEM micrographs at two different magnifications of a wall surface of a monolithic substrate formed in accordance with Example 44 disclosed in Table 9 herein.

[0056] FIGS. 11A and 1 IB are SEM micrographs at two different magnifications of a polished cross-section of a monolithic substrate formed in accordance with Example 50 disclosed in Table 9 herein.DETAILED DESCRIPTION OF THE INVENTION

[0057] Reference will now be made in detail to certain aspects of the disclosed subject matter. While the disclosed subject matter will be described in conjunction with the enumerated claims, it will be understood that the exemplified subject matter is not intended to limit the claims to the disclosed subject matter.

[0058] Throughout this document, values expressed in a range format should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a range of “about 0.1% to about 5%” or “about 0.1% to 5%” should be interpreted to include not just about 0. 1% to about 5%, but also the individual values (e.g., 1%, 2%, 3%, and 4%) and the sub-ranges (e.g., 0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4.4%) within the indicated range. The statement “about X to Y” has the same meaning as “about X to about Y,”unless indicated otherwise. Likewise, the statement “about X, Y, or about Z” has the same meaning as “about X, about Y, or about Z,” unless indicated otherwise.

[0059] In this document, the terms “a,” “an,” or “the” are used to include one or more than one unless the context clearly dictates otherwise. The term “or” is used to refer to a nonexclusive “or” unless otherwise indicated. The statement “at least one of A and B” or “at least one of A or B” has the same meaning as “A, B, or A and B.” In addition, it is to be understood that the phraseology or terminology employed herein, and not otherwise defined, is for the purpose of description only and not of limitation. Any use of section headings is intended to aid reading of the document and is not to be interpreted as limiting; information that is relevant to a section heading may occur within or outside of that particular section.

[0060] In the methods described herein, the acts can be carried out in a specific order as recited herein. Alternatively, in any aspect(s) disclosed herein, specific acts may be carried out in any order without departing from the principles of the invention, except when a temporal or operational sequence is explicitly recited. Furthermore, specified acts can be carried out concurrently unless explicit claim language recites that they be carried out separately or the plain meaning of the claims would require it. For example, a claimed act of doing X and a claimed act of doing Y can be conducted simultaneously within a single operation, and the resulting process will fall within the literal scope of the claimed process.

[0061] The term “and / or” as used herein means the stated possibilities in the alternative or any combination thereof. For example, “A, B, and / or C” means A, B, C, or a combination thereof.

[0062] The term “about” as used herein can allow for a degree of variability in a value or range, for example, within 10%, within 5%, or within 1% of a stated value or of a stated limit of a range, and includes the exact stated value or range.

[0063] The term “substantially” as used herein refers to a majority of, or mostly, as in at least about 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or at least about 99.999% or more, or 100%. The term “substantially free of’ as used herein can mean having none or having a trivial amount of, such that the amount of material present does not affect the material properties of the composition including the material, such that about 0 wt% to about 0.1 wt% of the composition is the material, or about 0 wt% to about 0.01 wt%, or about 0.1 wt% or less, or less than, equal to, or greater than about 0.9 wt%, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.08, 0.06, 0.04, 0.02, 0.01, or about 0.001 wt% or less, or about 0 wt%.

[0064] Various aspects of the present disclosure provide a monolithic substrate. The monolithic substrate can comprise a ceramic and / or glass matrix. In various aspects, the monolithic substrate may the ceramic and / or glass matrix may be referred to as composed of a comprise a glass and ceramic composite material. As referred to herein, a glass-ceramic composite material is a material that comprises both glass (amorphous) and ceramic (crystalline) materials (particles) sintered together. The ceramic and / or glass matrix can include a continuous interconnected pore structure having a porosity of at least 48% and preferably at least 50% or even higher.

[0065] As described herein, the pore size distribution of the interconnected pore structure can be substantially monomodal or multimodal. In either case, a significant portion of the porosity, e.g., at least 20%, is contributed by pores having a pore diameter between 0. 1 pm and 1 pm. In some embodiments, particularly those having a monomodal pore size distribution (e.g., as a result of no pore former addition), from 80% to 100% of the porosity can be contributed by pores having a pore size between 0.1 pm and 1 pm. Furthermore, according to embodiments herein, at most some relatively small portion of the porosity, e.g., at most 5%, 3%, or even 1% of the porosity is contributed by pores smaller than 0.1 pm. Accordingly, the monolithic substrates disclosed herein may be considered as microporous.

[0066] In particular, it has been discovered by the current inventors that a porous substrate coated with a sorbent that has a significant contribution of its porosity provided by pores within the range of 0.1 pm to 1 pm facilitates the ability of many sorbents, such as polyethylenimine (PEI) or other amine-based sorbents, to cyclically adsorb and desorb carbon dioxide. For example, the carbon capture performance of many sorbents (and / or sorbent-laden articles) have been experimentally determined with respect to the sorbent contained within a closed atmosphere. But as a consequence, these experiments do not account for realistic conditions under which a carbon capture system would be operated, in which the sorbent is subjected to a constantly moving flow of carbon dioxide-containing fluid (e.g., air) .Without wishing to be bound by theory, it is believed that pores within this size ranges disclosed herein advantageously account for the realistic conditions, and enable the substrate to carry an comparatively large amount of sorbent while preserving a suitable amount of open porosity to provide fast kinetics for the air or other carbon dioxide-containing fluid to quickly make contact with the sorbent, as well as providing a beneficial dwell time between the sorbent and the flow of carbon dioxide-containing fluid (e.g., air).

[0067] Unless stated otherwise herein, the porosity of the interconnected pore structure, as well as the pore size (which may be interchangeably referred to as the pore diameter) of the pores of the interconnected pore structure can be determined as an assumed spherical median pore diameter via mercury porosimetry. Unless stated otherwise, porosity, bulk density, apparent density, pore size, pore size distribution, or other porosity-related or porositydependent characterizations are determinable by mercury porosimetry. Mercury porosimetry can be performed as per ASTM D6761-07 (2012).

[0068] The monolithic substrates disclosed herein can have, for example, a honeycomb form or configuration, which may interchangeably be referred to herein as “honeycomb bodies”, “honeycomb articles” or simply “honeycombs”, as well as “honeycomb monolith” or similar. The honeycomb bodies comprise an intersecting array of walls (the glass and / or ceramic matrix, such as made of a glass-ceramic composite material) that define a plurality of channels extending axially through the body. In addition, honeycombs may be referred to as “cellular” in that each grouping of the walls that borders and encloses one of the channels can be referred to as a cell.

[0069] For example, FIG. 1 illustrates an embodiment for a monolithic substrate in the form of a honeycomb body 100 comprising an array or matrix of intersecting walls 102 that define channels 104 extending axially or longitudinally through the body 100 from a first end face 106 to a second end face 108. The shape of the body 100 is defined by an outer skin or periphery 105. Each enclosed segment of walls 102 defining one of the channels 104 may be referred to as a cell, such that the body 100 and other honeycomb bodies may alternatively be referred to as cellular. In accordance with this disclosure, the walls 102 can be made of the porous glass-ceramic composite materials described herein.

[0070] The monolithic substrate can optionally include a coating. The coating can include any suitable material, such as a sorbent (e.g., a sorbent that adsorbs and desorbs CO2), a catalyst (e.g., a catalyst for a catalytic converter, or another catalyst), or a combination thereof. The coating can be continuous or discontinuous. The monolithic substrate can include a monomodal pore size distribution, a bimodal pore size distribution, a trimodal pore size distribution, or a multimodal pore size distribution that is greater than a trimodal pore size distribution.

[0071] Bulk density as referred to herein is calculated as the mass of the substrate divided by the total volume that the substrate occupies, wherein the total volume that the substrate occupies includes the volume of the sintered particles (solid matter) as well as anyporosity, such as both the inter-particle void volume (e.g., interstitial spacing between particles due to particle packing and / or pore former removal) and internal pore volume (e.g., inherent porosity of the particles used), but does not include the volume of the longitudinal channels (e.g., portions of the substrate when viewed from a longitudinal end of the substrate that are considered to be open frontal area).

[0072] The total volume that a substrate with a honeycomb configuration or form occupies can be defined, when viewed from a longitudinal end of the substrate, as a first portion considered to correspond to a closed frontal area (CFA) and a second portion considered to correspond to an open frontal area (OFA), with the CFA and OFA given as complementary percentages that sum to 100%. In particular, the OFA corresponds to the portions of the cross- sectional area occupied by the open channels of the honeycomb configuration of the substrate, while the CFA corresponds to the remaining portions occupied by the matrix of intersecting walls. Monolithic substrates having a honeycomb form or configuration may be referred to herein interchangeably as honeycombs, honeycomb articles, honeycomb bodies, or honeycomb monoliths.

[0073] For example, the monolithic substrate (e.g., absent any coatings added thereto) can have a bulk density of less than 1.5 g / cm3, less than 1.4 g / cm3, less than 1.3 g / cm3, less than 1 .2 g / cm3, and preferably less than 1.1 g / cm3or even less than 1 g / cm3, including ranges having these values as upper endpoints, such as from 0.5 g / cm3to 1.5 g / cm3, from 0.5 g / cm3to 1.2 g / cm3, or from 0.5 g / cm3to 1. 1 g / cm3. The monolithic substrate (e.g., absent any coatings added thereto) can have any suitable total pore volume, as determined via mercury porosimetry, such as greater than 40%, at least 48%, at least 50%, at least 55%, at least 60%, or even at least 65%, at least 70%, or at least 75%, such as in the range of 48% to 75% or 48% to 80%, or other range having these values as endpoints, such as from 50% to 75%, or from 50% to 80%.

[0074] The monolithic substrate can have any suitable flexural strength in a 4-point bend test of the monolithic substrate, such as performed per ASTM-D6272. For ease of comparison of honeycomb monoliths having different geometries, the strength can be normalized by the CFA of the monolithic substrate. For example, the monolithic substrate can have a flexural strength in a 4-point bend test of the monolithic substrate normalized by the CFA of the monolithic substrate (i.e., divided by the CFA of the monolithic substrate, given as a percentage) of greater than 500 psi, or in the range of 500 psi to 3000 psi, or 1000 psi to 2600 psi, or less than or equal to 3000 psi and greater than or equal to 500 psi and less than, equalto, or greater than 600 psi, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, or 2900 psi.

[0075] The monolithic substrate can have any suitable physical form. In various aspects, the physical form is that of a honeycomb form (e.g., an extruded honeycomb form), having a plurality of cells therein, the cells that define parallel channels running longitudinally through the honeycomb form. The cells can be formed by an array or matrix of intersecting walls (e.g., the ceramic and / or glass matrix). The honeycomb form can have any suitable circumferential profile or shape, such as that of a circle, oval, square, rectangle, hexagon, triangle, polygon, or irregular shape. When viewed from an end of the honeycomb form, the cells can have any suitable profile, such as a profile of a circle, oval, square, rectangle, hexagon, triangle, polygon, or irregular shape, such as a honeycomb shape. For example, one possible combination is a cylindrical substrate (circular circumferential profile) that has square-shaped cells. The use of a honeycomb form can advantageously result in a lower pressure drop of a fluid stream flowing from one axial end of the monolith to the other end in comparison to other forms (such as packed pellet beds). The honeycomb form can include any suitable number of cells per square inch (e.g., as measured when viewed from an end), such as 20 to 1000 cells per square inch, or 50 to 600, or less than or equal to 1000 cells per square inch and greater than or equal to 20 squares per square inch and less than, equal to, or greater than 40 squares per square inch, 60, 80, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, 320, 340, 360, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, or 950 cells per square inch. The cells in the honeycomb form have any suitable wall thickness, such as a wall thickness of 0.001 inches to 0.1 inches, or 0.002 inches to 0.05 inches, or less than or equal to 0.1 inches and greater than or equal to 0.001 inches and less than, equal to, or greater than 0.002 inches, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, 0.01, 0.011, 0.012, 0.013, 0.014, 0.015, 0.016, 0.017, 0.018, 0.019, 0.02, 0.025, 0.03, 0.035, 0.04, or 0.045 inches. In various aspects, the cells in the honeycomb form can include a geometry of 100 / 8 or 200 / 8 cells per square inch / 0.001” wall thickness.

[0076] The monolithic substrate can have any suitable open frontal area. The open frontal area (or OFA) is the percent cross-sectional area of the longitudinal channels in the honeycomb form that is, for example, available for gas to flow therethrough. In contrast, the closed frontal area (or CFA) is the percent cross-sectional (perpendicular to the axial or longitudinal direction) area of the intersecting walls of the substrate (i.e., excluding the open frontal area). For example, the monolithic substrate can have an open frontal area of 70-95%,75-90%, 78-85%, or less than 95% and greater than or equal to 70% and less than, equal to, or greaterthan 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, or 94%.

[0077] The monolithic substrate can optionally include a coating including a catalyst, a sorbent that adsorbs and desorbs CO2, or some other functional material, or a combination thereof. In various aspects, the coating can be directly adhered to the material of the glass and / or ceramic matrix, wherein the monolithic substrate is free of an intervening bonding layer between the coating and the glass and / or ceramic matrix. However, in various aspects, the monolithic substrate can include a bonding layer. The bonding layer can be any suitable bonding layer. The bonding layer can be a washcoat material. The bonding layer can include a deposition of high surface area particles, such as gamma alumina, zeolite, activated carbon, or a combination thereof. A coating that includes a sorbent can be only the sorbent or can include one or more other components. A coating that includes a catalyst can be only the catalyst or can include one or more other components. The sorbent can be any suitable sorbent that adsorbs and desorbs CO2, such as a zeolite, sodium carbonate, activated carbon, carbon nanotubes, a metal-organic framework (MOF), an amine, or a combination thereof. The monolithic substrate including a coating including a sorbent and / or catalyst can include any suitable loading level of the sorbent or of the catalyst, such as 0.1 wt%to 99% (e.g., wherein 0.1 wt% to 99 wt% of the monolithic substrate including the coating is the sorbent or catalyst), 1 wt% to 90 wt%, or less than or equal to 99% and greater than or equal to 0.1 wt% and less than, equal to, or greater than 1 wt%, 2, 4, 6, 8, 10, 12, 16, 18, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 82, 84, 86, 88, 90, 91, 92, 93, 94, 95, 96, 97, or 98 wt%.

[0078] The monolithic substrate can be an shaped, dried, and fired product of a formable mixture, which may be referred to as a batch, batch mixture, or batch composition. For example, shaping or forming can be accomplished by extrusion of the batch mixture, such as through a honeycomb extrusion die to impart a honeycomb configuration to the monolithic substrate. Accordingly, the batch mixture can comprise one or more types of inorganic particles for forming the matrix (e.g., array of intersecting walls) of the substrate as a result of firing the green substrate to sinter the particles together. For example, the batch mixture can comprise a combination of glass, ceramic, and / or ceramic precursor particles as described further herein and particular combinations of which are provided with respect to the Examples.

[0079] In some embodiments, the inorganic particles can be selected as those that have relatively poor packing, such as platy (plate-like) particles that creates spaces or interstices (andtherefore increased porosity) when the platy particles are packed together. The inorganic particles can be selected so that they are stable to firing at a temperature of at least 600°C, such as temperatures up to 1000°C. The batch can additionally include a liquid carrier, such as water, an organic binder, such as methylcellulose, a lubricant or extrusion aid, such as an oil or fatty acid, and / or a sintering aid that facilitates the sintering of the inorganic particles together during firing.

[0080] The inorganic particles for forming the matrix, such as in the form of a glassceramic composite material, can be stable (e.g., does not pyrolyze or degrade) during firing (e.g., firing under any suitable gas, such as including air, inert gas, oxygen (e.g., 5 to 21% oxygen), or a combination thereof) at 600 °C (e.g., at or below 600 °C), 950 °C, 1100 °C, or at less than or equal to 1100 °C and greater than or equal to 600 °C and less than, greater than, or equal to 650, 700, 750, 800, 850, 900, 950, 1000, or 1050 °C. In some aspects, higher temperatures (e.g., temperatures above about 1050 °C or even above about 1000 °C) are avoided, as these higher temperatures tend to result in not only the sintering of inorganic particles, but also the reaction of inorganic particles into one or more ceramic phases. While some degree of chemical reaction is expected to occur, particularly at the interfaces between particles, the firing conditions can be selected to primarily sinter the inorganic particles together in order to substantially preserve the inorganic particles (e.g., preserve the shape and size of the inorganic particles, as well as any inherent porosity of the inorganic particles).

[0081] The inorganic particles can have any suitable particle diameter, such as a median particle diameter of 0.2 microns to 20 microns, or less than or equal to 20 microns and greater than or equal to 0.2 microns and less than, equal to, or greater than 0.4, 0.6, 0.8, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, or 19 microns. The inorganic particles can include a silicate, aluminate, oxide, glass, carbide, or combination thereof. More specifically, the inorganic particles can include diatomaceous earth, quartz, fused silica, cordierite, clay, talc, zeolite, spinel, wollastonite, mica, basalt, feldspar, aluminum oxide, aluminum hydroxide, a glass powder, silicon carbide, or a combination thereof.

[0082] The inorganic particles can form any suitable proportion of the batch mixture, on a dry weight basis, such as 50 wt% to 90 wt% of the batch mixture, 60 wt% to 80 wt%, or less than or equal to 90 wt% and greater than or equal to 50 wt% and less than, equal to, or greater than 52 wt%, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, or 88 wt%. As described herein, the inorganic particles for forming the first pores can form pores viainterstices between the particles, via pores present in the particles themselves, or a combination thereof.

[0083] Additionally, since the liquid component and organics in a batch mixture are expected to bum out or otherwise be removed during drying and firing, and by selecting firing conditions that sinter the particles together while preserving the particles and interstices as described herein, the wt% of each inorganic particle ingredient in the batch mixture, with respect to 100% inorganics in the batch mixture, is expected to correspond approximately to the wt% of the corresponding inorganic particles in the resulting monolithic substrate. Accordingly, for the purposes of this disclosure, any values or ranges provided herein for the amount of inorganic particles in a batch mixture, with respect to 100% inorganics in the batch mixture, are intended in this disclosure to also refer to the approximate amount of the corresponding inorganic particles in the resulting monolithic substrate. For example, 50 wt% diatomaceous earth particles in the batch mixture with respect to 100% inorganics in the batch mixture is to be understood as also referring to diatomaceous earth comprises about 50 wt% of the inorganic particles in the resulting monolith substrate (after the liquid component and organic components are removed during drying and firing).

[0084] Accordingly, the inorganic particles that sinter together to form the glass and / or ceramic matrix and result in the formation of the first and / or fine pores (e.g., due to inherent porosity of the particles and / or interstices formed between the particles during packing), such as any combination of one or more of diatomaceous earth, hollow glass microspheres, and platy talc, can form any suitable proportion of the monolithic substrate, such as at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 75 wt%, at least 80 wt%, at least 90 wt%, or even up to 95 wt%, including ranges having these values as end points, such as from 50 wt% to 60 wt%, from 50 wt% to 70 wt%, from 50 wt% to 75 wt%, from 50 wt% to 80 wt%, from 50 wt% to 90 wt%, from 50 wt% to 95 wt%, from 60 wt% to 70 wt%, from 60 wt% to 75 wt%, from 60 wt% to 80 wt%, from 60 wt% to 90 wt%, from 60 wt% to 95 wt%, from 70 wt% to 80 wt%, from 70 wt% to 90 wt%, from 70 wt% to 95 wt%, from 75 wt% to 90 wt%, from 75 wt% to 95 wt%, from 80 wt% to 90 wt%, from 80 wt% to 95 wt%, or even from 85 wt% to 95 wt%.

[0085] The inorganic particles of the monolithic substrate can comprise diatomaceous earth particles in an amount of at least 30 wt%, at least 35 wt% at least 40 wt%, at least 45 wt%, at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 75 wt% such as up to 80 wt%, or even 85 wt% of the monolithic substrate, including ranges having these values as endpoints, such as from 30 wt% to 50 wt%, from 30 wt% to 60 wt%, from 30 wt% to 70 wt%, from 30wt% to 75 wt%, from 30 wt% to 80 wt%, from 30 wt% to 85 wt%, from 40 wt% to 50 wt%, from 40 wt% to 60 wt%, from 40 wt% to 70 wt%, from 40 wt% to 75 wt%, from 40 wt% to 80 wt%, from 40 wt% to 85 wt%, from 50 wt% to 60 wt%, from 50 wt% to 70 wt%, from 50 wt% to 75 wt%, from 50 wt% to 80 wt%, from 50 wt% to 85 wt%, from 60 wt% to 75 wt%, from 60 wt% to 80 wt%, from 75 wt% to 85 wt%, or even from 80 wt% to 85 wt% of the monolithic substrate.

[0086] The inorganic particles of the monolithic substrate can comprise platy talc particles in an amount of at least 15 wt%, at least 20 wt%, or at least 30 wt% when used in combination with other particles to form the first pores (e.g., when used together with diatomaceous earth), and when used as a primary component for forming the first pores plat talc can comprise at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, or even up to 95 wt% of the monolithic substrate, including ranges having these values as endpoints, such as from 50 wt% to 60 wt%, from 50 wt% to 70 wt%, from 50 wt% to 80 wt%, from 50 wt% to 90 wt%, from 50 wt% to 95 wt%, from 60 wt% to 70 wt%, from 60 wt% to 80 wt%, from 60 wt% to 90 wt%, from 60 wt% to 95 wt%, from 70 wt% to 80 wt%, from 70 wt% to 90 wt%, from 70 wt% to 95 wt%, from 80 wt% to 90 wt%, from 80 wt% to 95 wt%, or even from 90 wt% to 95 wt% of the monolithic substrate.

[0087] The inorganic particles of the monolithic substrate can comprise hollow glass microsphere particles in an amount of at least at least 20 wt%, at least 25 wt%, at least 30 wt%, or at least 35 wt% of the monolithic substrate when used in combination with other particles to form the first pores (e.g., when used together with diatomaceous earth and / or talc), such as up to 50 wt% of the monolithic substrate, including ranges having these values as endpoints, such as from such as from 20 wt% to 30 wt%, from 20 wt% to 35 wt%, from 20 wt% to 40 wt%, from 20 wt% to 45 wt%, from 20 wt% to 50 wt%, from 30 wt% to 40 wt%, from 30 wt% to 45 wt%, from 30 wt% to 50 wt%, from 35 wt% to 40 wt%, from 35 wt% to 45 wt%, from 35 wt% to 50 wt%, from 40 wt% to 45 wt%, from 40 wt% to 50 wt% of the monolithic substrate.

[0088] The binder can include any suitable binder that improves extrusion, formability, and / or green strength, such as methylcellulose or other cellulose derivative. The binder can form any suitable proportion of the extrudable composition, on a dry weight basis, such as 4 wt% to 10 wt%.

[0089] In various aspects, the sintering aid can include a material that includes a crystalline or glassy structure. The sintering aid can comprise a borate, a phosphate, a transition metal oxide, an oxide, a hydroxide, a carbonate, a silicate (e.g., alkali earth silica and / or alkalineearth silicate), an alumino-silicate, Fe20s, boric acid, K2CO3, or other potassium source. The sintering aid can form any suitable proportion of the batch mixture, such as 1 wt% to 30 wt% of the batch mixture, depending on the material used. In particular, sintering aids that comprise alumina or silica (e.g., feldspar, mica, hollow glass microspheres) can be provided in a relatively high amount, such as from 10 wt% to 30 wt%, while other sintering aids are generally provided in an amount of less than 6 wt%, such as from 1 wt% to 6 wt%, with respect to 100% inorganics in the batch mixture.

[0090] The batch mixture can further include a pore-forming material for forming the coarse and / or second pores, or otherwise increasing the porosity of the material. The poreforming material can include any suitable material that degrades, decomposes, and / or pyrolyzes (e.g., bums out) during the firing to leave behind pores in the material that approximately corresponding to the particle size of the pore-forming material. The pore-forming material can be any suitable pore-forming material, such as a vegetable starch (e.g., a cross-linked starch), a nut-shell flour, carbon, a natural polymer, a synthetic polymer, a carbonaceous material, crystalline carbon, amorphous carbon, or a combination thereof. If included, the pore forming material can form any suitable proportion of the batch mixture, on a dry weight basis, such as 5 wt% to 45 wt% of the batch mixture, 10 wt% to 35 wt% of the batch mixture, or less than or equal to 45 wt% and greater than or equal to 5 wt% and less than, equal to, or greater than 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, or 44 wt%. With respect to total inorganics (as opposed to total dry weight), the pore former can be provided in the batch mixture in an amount of 10 wt% to 50% as a superaddition with respect to 100% inorganic particles in the batch mixture, such as from 20 wt% to 40 wt% superaddition. In various aspects, the batch mixture can be substantially free of the pore-forming material; for example, the poreforming material can be 0 wt% of the batch mixture, or 0 wt% to 5 wt%, or less than or equal to 5 wt%, 4, 3, 2.5, 2, 1.5, 1, 0.5, 0.1, or less than or equal to 0.01 wt%.

[0091] The addition of a pore former can be useful in embodiments where additional porosity is desired, and in particular, where a bimodal or other multimodal pore size distribution is desired. That is, the pore former can be utilized to provide the “coarse pores” or “second pores” as referred to herein with respect to monolithic substrates having a multimodal pore size distribution. The organic pore former particles can have any suitable size, such as a median particle size of from 5 to 40 pm, depending on the desired size of the pores to be imparted by the pore former.

[0092] FIGS. 2, 5A-5B, and 11A-11B show examples that utilize significant amounts of pore former (e.g., 30-40 wt% as superaddition), and the resulting pores can be readily identified as large black voids in the material for these examples. In contrast, in some embodiments no additional organic pore former is utilized (i.e., 0 wt% in the batch), such as shown in the examples of FIGS. 9A-9B and 10A-10B. The examples utilizing no pore former addition correspondingly exhibit substantially monomodal pore size distributions (e.g., a single differential intrusion peak). Even without any organic pore former addition, porosities of over 50% are advantageously still achievable due to combination of inherent porosity of the inorganic particles that form the material of the monolithic substrate and the interstitial spacing due to particle packing, which are both achieved by preserving the inorganic particles during sintering, as described herein. While the inherent porosity of the raw materials and the interstitial spacing due to particle packing are two different sources of porosity, the pores resulting from these sources are similar in size (e.g., in the range of 0.1 pm to 1 pm), and therefore are expected to typically combine into a single pore size distribution peak.

[0093] The batch mixture can further include one or more liquid components, such as an aqueous or organic liquid component. The liquid component can be or include water. The liquid component can form any suitable proportion of the batch mixture to impart a desirable extrudability, plasticity, and / or formability to the batch mixture, such as 5 wt% to 100 wt%, or 40 wt% to 85 wt%, as a super addition with respect to 100% of a total weight of dry solids in the batch mixture.

[0094] In various aspects, the present disclosure provides a method of forming the monolithic substrate. The method can include shaping or forming a batch mixture into a desired shape, such as via extrusion. Before firing, the shaped article can be referred to as a green body. The method can include drying the green body. The method can also include firing the green body, to form the monolithic substrate according to one or more embodiments described herein. The method can optionally include applying a coating to the monolithic substrate, wherein the coating includes a catalyst for treatment or abatement of one or more pollutants, a sorbent that can absorb and desorb CO2, or a combination thereof.

[0095] The drying can be any suitable drying that substantially removes the liquid carrier from the green body. The drying can include heating, air flow, and / or exposing to microwave or other energy source. The drying can include placing the green body under a vacuum. The drying can include drying at a sufficient temperature and for a sufficient duration to substantially remove all liquid carrier from the green body (e.g., such that the green bodyhas a liquid carrier content less than 5 wt%, or less than 2 wt%, less than 1 wt%, less than 0.5 wt%, or less than 0.1 wt%).

[0096] The firing can be any suitable firing (e.g., heating for a suitable duration, at a suitable temperature, and under a suitable atmosphere) that sinters one or more of the components of the green body together. Firing can also be used to decompose and / or pyrolyze (bum out) any pore-forming materials for forming additional porosity in the interconnected pore structure of the ceramic and / or glass matrix described herein. The firing can be conducted under any suitable atmosphere, such as any suitable gas, such as including air, inert gas (e.g., nitrogen), oxygen (e.g., 5 to 21% oxygen), or a combination thereof. The firing can include firing at a firing temperature sufficient to cause reaction and / or sintering of the sintering aid and / or the inorganic particles, such as a firing temperature of 600 °C to 1100 °C, such as at less than or equal to 1100 °C and greater than or equal to 600 °C, at greater than 700 °C and / or less than 1000 °C, and less than, equal to, or greater than 650, 700, 750, 800, 850, 900, 950, 1000, or 1050 °C. The firing can include firing for a duration of 1 h to 24 h, or 2 h to 6 h, or less than or equal to 24 h and greater than or equal to 1 h and less than, equal to, or greater than 2 h, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20, or 22 h.

[0097] The firing temperature and type of inorganic particles can be selected such that the particles of the inorganic particles are sintered together as a result of the firing process, but without significant reaction of the particles into one or more ceramic phases. That is, the inorganic particles and firing conditions are selected according to the present disclosure so that the particles are sintered together, but any reaction into ceramic phases is restricted primarily to the interfaces between particles where the sintering occurs. In this way, the shape, size, and any inherently porosity of the inorganic particles is substantially preserved after firing, such that the monolithic body is effectively formed as an agglomeration of the inorganic particles sintered together.

[0098] For example, as shown in the examples of FIG. 2, FIGS. 5A-5B, FIGS. 9A-9B, FIGS. 10A-10B, and FIGS. 11A-11B, the individual inorganic particles (primarily talc particles in the case of FIG. 2 and primarily diatomaceous earth particles in the case of FIGS. 5A-5B, 9A-9B, 10A-10B, and 11A-1 IB) largely retain their original shape and size even after being fired into a monolith. As a result, the monoliths disclosed herein (and as exhibited by the aforementioned examples) can each be described as an agglomerate of sintered particles. In comparison, ceramic precursor particles used as raw materials in traditional ceramics manufacturing may be fired for a duration and at a temperature sufficient to more fully reactthe precursor particles to transform the precursors into one or more ceramic phases, thereby converting a green body into a homogeneous construct of one or more ceramic phases. However, the reaction of ceramic precursors into ceramic phases correspondingly causes the inherent porosity and interstitial spaces between the original precursor particles to be mostly if not completely destroyed. Thus, by preserving the nature of the particles in the inorganic particles after sintering (creating the monoliths as agglomerates of sintered particles), the inherent porosities as well as the spaces or interstices between the particles are correspondingly also preserved, which results in increased porosity in the monoliths as disclosed herein.

[0099] In various aspects, the monolithic substrates can include particles that are sintered together but that are still visible as discrete particles under SEM. While the particles are largely preserved during sintering, it is expected that some small degree of reaction into ceramic phases and / or formation of amorphous material is to occur during sintering, particularly at the interfaces between particles. Additionally, many of the suitable ceramic precursor raw materials useful as the inorganic particles are crystalline (such as clay, talc, or other minerals) and therefore the sintered monolithic substrates herein have these crystalline phases imparted directly from the inorganic particles even without further chemical reaction into new ceramic phases. Accordingly, the inorganic particles can sinter together during the firing but can retain portions of their particulate-shapes within the ceramic and / or glass matrix, as well as their inherent porosity, crystalline structure, or other characteristics. In various aspects, preservation of the inorganic particles during firing can provide formation of at least a portion of the interconnected pore network of the material of the monolithic substrates, such as the “first pores” as referred to herein with respect to multimodal pore size distributions.

[0100] Various aspects of the present disclosure provide a method of using the monolithic substrate that includes a coating thereon that includes a sorbent that can adsorbs and desorbs CO2. The method can include exposing the monolithic substrate to a gas stream that includes CO2 to at least partially adsorb the CO2 from the gas stream. The method can also include desorbing the CO2 from the coating on the monolithic substrate. In various aspects, desorbing the CO2 from the coating on the monolithic substrate includes heating the monolithic substrate, such as via resistive heating, sending hot gas (e.g., steam) through the monolithic substrate, microwave heating, induction heating, via an external heat source at a periphery of the monolithic substrate, or a combination thereof. In various aspects, desorbing the CO2 from the coating can include sequestering the CO2, such as placing the CO2 in a storage tank.

[0101] The methods of using the monolithic substrate described herein can be used for any suitable method of CCE-rcmo val. such as direct air capture (DAC) or point source capture of CO2 at an effluent source. The monolithic substrate described herein can be capable of withstanding temperatures of 200 °C or more and withstanding moist environments.

[0102] Various aspects of the present disclosure provide a method of using the monolithic substrate that includes a coating thereon that includes a catalyst. The method can include exposing the monolithic substrate to a gas stream to catalyze a chemical reaction of one or more components of the gas stream using the catalyst.Examples

[0103] Various aspects of the present disclosure can be better understood by reference to the following Examples which are offered by way of illustration. The present disclosure is not limited to the Examples given herein. Firing was conducted under 5-21% oxygen in air or in a mixture of air and nitrogen. Mercury porosimetry was performed as per ASTM D6761-07 (2012). The monoliths may be referred to in the description of the Examples interchangeably as honeycombs, monoliths, parts, pieces, bodies, samples, or articles.

[0104] Batch mixtures, firing conditions, and physical properties of the resulting substrate are shown in Tables 1-2. Tables 3 and 4 show the same examples as Tables 1 and 2, respectively, but with the dry inorganic and organic components provided in wt% with respect to 100% dry solids in the mixture (as opposed to with respect to 100% inorganics as in Tables 1-2). Since Examples in Tables 3 and 4 are the same as those in Tables 1 and 2, the firing conditions and properties are not repeated in Tables 3 and 4.

[0105] Accordingly, in Tables 1-2, inorganics are provided in wt% and organic materials provided in wt% as superaddition with respect to 100% inorganics. The inorganic materials and organic materials together yield a total for dry solids in the mixture. In Tables 3- 4, the dry inorganics and organics are provided with respect to 100% dry solids. The water and oil (MOx) are also given in wt%, but in terms of superaddition to 100 parts total dry solids (the sum of inorganics and organics together). Since the liquid component and organics are expected to bum out during firing, the wt% of each inorganic particle component in the batch mixture is expected to correspond approximately to the wt% of each inorganic particles in the resulting monolithic substrate. Accordingly, any values or ranges for the amount of inorganic particles in the batch mixtures are intended in this disclosure to refer to the amount of that material as the inorganic particles in the resulting monolithic substrate. For example, 50 wt%diatomaceous earth particles in the batch mixture with respect to 100% inorganics in the batch mixture is to be understood as also referring to 50 wt% of diatomaceous earth of the inorganic particles in the resulting monolith substrate (after the liquid component and organic components are removed during drying and firing).

[0106] The first set of rows show the inorganic raw materials used and the amount used (wt%). Diafil 525 and Celtix are types of diatomaceous earth. Tecosil 44C is fused silica. C70 HGMS is hollow glass microspheres having an average particle size of 15 microns. Kaolin clay and platy talc particles were also used in some examples. While the packing of all of the particle materials contributed at least partially to the formation of the fine pores due to incomplete packing of the particles, in particular the diatomaceous earth, hollow glass microspheres, and talc particles contributed most significantly to formation of the first (fine) pores as described herein. As a result, the monoliths created in accordance with the Examples were agglomerates of sintered particles consistent with the disclosure herein, where the particulate matter was primarily (at least 50 wt% of dry ingredients) a combination of one or more of diatomaceous earth, hollow glass microspheres, or talc. However, as described herein, any other combination of particles having inherent porosity and / or packing behavior that results in the formation of interstices between particles, could be used. The clay and fused silica also functioned as a filler, and the mica particles as a sintering aid to assist in ensuring the inorganics yielded a suitably strong monolith after sintering. Two different types of mica were added for filler and sintering aid purposes in the form of Suzorite 325 Phlogopite and C4000 Muscovite. Potassium carbonate (K2CO3) and boric acid were also used as sintering aids as summarized in the Tables.

[0107] The organic materials and water used are shown next and the amounts used are given in terms of superadditions to 100 parts inorganics. The pea starch is cross-linked pea starch. MOx refers to an antioxidant-stabilized lubricating mineral oil.

[0108] Unless stated otherwise, the inorganics (e.g., inorganic particles and sintering aids) in the present Examples were first dry mixed in a Littleford mixer, followed by addition of water and organics with an additional wet mix cycle. The wet powder was then transferred into a 40 mm twin screw mixer and extruded through 2” diameter dies of either 100 cells per square in (cpsi) / 8 mil slots, 200 cpsi / 8 mil slots, or 400 cpsi / 4 mil slots, as indicated in the Tables. The parts were dried in a microwave dryer and fired in a gas kiln to temperatures in the range of 750 °C to 950 °C for 4 hours, as also indicated in the Tables.

[0109] Tables 1-2 next show the firing soak temperature. Each part sample was heated at a rate of 50 °C / hr to the soak temperature where it was held for 4 hours. The geometry isgiven as a nominal cell density (cells / in2or cpsi) and web thickness in mils. For example, a 100 / 8 geometry refers to a part with a nominal cell density of approximately 100 cpsi and a wall thickness of 8 mils. CFA is the closed frontal area of the honeycomb body in percent determined as the two-dimensional cross-sectional area (perpendicular to the axial length) of the matrix portion of the substrate (thus excluding the open channels). Bulk density of the porous material is given in the next row (independent of the channels of the honeycomb structure) as measured by mercury porosimetry. Porosity is a vol% determined by mercury porosimetry. The median pore diameter (of the entire pore size distribution) is given next in microns as determined by mercury porosimetry. In the next two rows, the pore size corresponding to the coarse and fine peaks of the bimodal distributions are given (again, referring to the pore sizes at which the maximum value of the coarse and fine peaks of the differential intrusion plot is located). The next row gives the total mercury intrusion volume and the following row gives the mercury intrusion volume at the inflection point in the curve of cumulative intrusion volume as a function of pressure (or pore size). The next row gives a calculation of the percentage of coarse pore volume by dividing the intrusion volume up to the inflection point by the total intrusion volume and multiplying by 100. The next row shows the percentage of fine pore volume which can be calculated by subtracting the coarse pore volume % from 100 (or by dividing the fine pore intrusion volume (intrusion volume at the inflection point subtracted from the total intrusion volume) by the total intrusion volume and multiplying by 100). Modulus of rupture (MOR) is measured by a 4-point bend test of a rectangular bar cut out of the fired parts, as per ASTM D6272. In the last row, MOR is normalized by the CFA to eliminate influence of cell geometry. In some cases, multiple monoliths were manufactured from the same batch mixture but under different conditions, which is denoted by use of the same Example number appended with a different alphabetic suffix (e.g., Ex. 1A and Ex. IB were each made from the same batch mixture but under different firing temperatures).

[0110] Table 1: Example compositions, firing conditions, and physical properties of resulting multimodal substrates.

[0111] Table 2: Example compositions, firing conditions, and physical properties of resulting multimodal substrates, with organic materials and water given in terms of superadditions to 100 parts inorganics.

[0112] Table 3 : Example compositions corresponding to the Examples of Table 1 but reported in wt% with respect to 100% dry solids.

[0113] Table 4: Example compositions corresponding to the Examples of Table 2 but reported in wt% with respect to 100% dry solids.

[0114] A first composition (batch mixture) in accordance with Ex. 1A and IB was formed that was 93 wt% fine platy talc particles and 6.6 wt% sintering aid (5.9 wt% boric acid and 0.7 wt% K2CO3), with respect to 100% inorganics in the batch. To the composition wasadded 40 wt% superaddition of cross-linked pea starch, water, and the indicated organics. Each of the compositions was extruded into a honeycomb green body and the green bodies were fired at 950 °C (Ex. 1A) and 850 °C (Ex. IB) for 4 hours. FIG. 2 illustrates a SEM micrograph of a polished section of the resulting glass and / or ceramic material matrix, showing coarse pores (large dark areas) and fine pore structure (small dark areas) between the sintered particles (shown in gray / white). The coarse porosity is produced by the burnout of the starch particles during firing. These pores (which result in the coarse or second pores) are about 10-30 pm in diameter. The pores (first or fine pores) formed by inefficient packing of the talc particles are much smaller, by about an order of magnitude.

[0115] A sample made generally in accordance with Ex. IB was subjected to a mercury porosimetry test and the results are shown in FIGS. 3A-B. In particular, FIG. 3 A illustrates cumulative intrusion (as a function of pressure converted to equivalent spherical pore diameter) versus pore size diameter of the ceramic substrate, while FIG. 3B illustrates the differential intrusion versus pore size diameter of the ceramic substrate. The arrow in FIG. 3 A indicates the inflection point in the curve that can be used to distinguish the two portions of the distribution. Accordingly, these two distinct regions of pore sizes are shown in the differential intrusion plot of FIG. 3B, with a first peak, corresponding to the “first” or “fine” pores as referred to herein, having a first maximum value (e.g., mathematically identifiable by a first local maximum in the differential intrusion plot) that is located at about 0.4 pm and a second peak, corresponding to the “second” or “coarse” pores as referred to herein, having a second maximum value (e.g., again mathematically identifiable by a second local maximum in the differential intrusion plot) located at about 6 pm. In accordance with the preceding and consistent with the disclosure herein, reference to the location of a differential intrusion peak or other peak herein refers to the location of the maximum value of the peak with respect to the corresponding pore size, which can each be determined mathematically as a local maxima in the differential intrusion plot.

[0116] The peak corresponding to the coarse pores was formed from the burnout of the starch pore former is located at about 8 pm in the mercury porosimetry data. The peak located at about 0.4 pm corresponds to the pore sizes found in the spaces or interstices between the talc (or other) particles in the ceramic matrix portion (walls) of the substrate. A method to determine the relative volume in the coarse and fine portions of the distribution is to use the inflection point in the cumulative intrusion curve (indicated by the arrow in FIG. 3A). The mercury intrusion volume up to the inflection point can be counted toward the coarse part of thedistribution and the intrusion volume measured after the inflection point can be counted toward the fine portion of the distribution. In the example shown here, the total intrusion volume is 0.86 mL / g. The inflection point occurs at about 0.55 mL / g. Therefore, in this Example, the intrusion volume accounting for the coarse pores is 0.55 mL / g and that for the fine pores is the difference between the total intrusion volume (0.86 mL / g) and the coarse portion (0.55 mL / g) or 0.31 mL / g. Dividing the coarse intrusion volume by the total intrusion volume, the coarse pore size can be determined to account for 64% of the total. Doing the same for the fine pore size shows that the fine pore size accounts for 36% of the total.

[0117] The interstices between the particles can contribute to the fine pore size once the part is fired, as shown in the microstructure shown in FIG. 2, in which talc particles were used as the main inorganic component of the composition. Another option to produce the fine pore structure is the use of materials having an internal porosity within the particles of less than1 pm. An example of such a material is diatomaceous earth, which was used in Examples 2- 16. EIGS. 4A-B illustrate SEM micrographs of diatomaceous earth particles exhibiting a fine internal pore structure (EIG. 4A: Diafil 525 type diatomaceous earth, EIG. 4B: Celtix type diatomaceous earth). In EIGS. 4A-B, particles of having a diameter of about 10 pm can be seen having a fine pore structure within the individual particles. The fine pore structure in the particles can provide pore sizes less than 1 pm in the fired substrate, or even less than 0.5 pm, such as in the range of about 0.1 pm to 0.5 pm. In general, both type of diatomaceous earth particles result in monolithic substrates having similar properties and either type can be utilized. However, it has been recognized by the current inventors that use of the Celtix type (FIG. 4B) generally requires the inclusion of an increased amount of liquid carrier (water) during extrusion, which can increase the complexity of the extrusion process. Accordingly, many examples provided herein utilize the Diafil type (FIG. 4A) diatomaceous earth for relatively simplified manufacture of monolithic substrates.

[0118] The batch composition of Example 2 was formed comprising 80 wt% Diafil type diatomaceous earth particles (particles shown in FIG. 4A), 13.3 wt% talc, and 6.6 wt% sintering aid (5.9 wt% boric acid and 0.7 wt% K2CO3), with respect to 100% inorganics in the mixture, followed by superaddition of 20 wt% cross-linked pea starch, as well as water and the indicated inorganics. The composition was fired at 850 °C for 4 hours. FIG. 5A-5B illustrate SEM micrographs of a polished cross section of monolith formed in accordance with Example2 at two different magnifications. Large black areas are the coarse pores, while the fine porosity results from the combination of interstitial pores (pores between the particles) plus the poresizes within (inherent to) the diatomaceous earth particles themselves. FIGS. 5A-5B illustrates that the fine porosity from the diatomaceous earth particles survives the extrusion and firing processes under the stated conditions.

[0119] The pore sizes of the coarse and fine portions of the pore distributions can be manipulated to some extent by manipulating the raw materials in the batch composition. For example, the addition of more coarse pore former results in a higher volume of coarse porosity, such as shown in Examples 3-5 where the same inorganic particles are utilized at different amounts of pore former superaddition. Likewise, the amounts of the raw material with inherent fine porosity (such as diatomaceous earth) and the raw materials that result in interstices due to incomplete packing (such as talc) can may be increased or decreased to influence the fine pore size and thus also the ratio of fine to coarse pore size, such as shown in Examples 3-7 where the same diatomaceous earth, pore former, and talc ingredients are used but their respective amounts varied.

[0120] In Example 3, 50 wt% diatomaceous earth was used with respect to total inorganics in the mixture, with 40 wt% cross-linked pea starch superaddition prior to firing; Example 4 used 60 wt% diatomaceous earth, with 30 wt% cross-linked pea starch superaddition prior to firing; and Example 6 used 50 wt% diatomaceous earth was used, with 30 wt% cross-linked pea starch superaddition priorto firing. FIGS. 6A-C illustrate differential intrusion versus pore size distribution as measured during mercury porosimetry testing for fired ceramic monoliths. In particular, FIG. 6A illustrates the pore size distribution for Ex. 3, FIG. 6B illustrates the pore size distribution for Ex. 4, and FIG. 6C illustrates the pore size distribution for Ex. 6. Accordingly, FIGS. 6A-C show the influence of different levels of diatomaceous earth and cross-linked pea starch on the relative pore sizes of the coarse and fine distributions, with additional pore former (starch) addition tending to increase the size of the peak corresponding to the coarse pores and additional diatomaceous earth (having its own inherent porosity) tending to increase the size of the peak corresponding to the fine pores. In this way, the relative size of the first and second peaks (fine and coarse pores) can be influenced by adjusting the relative amounts of the raw materials that drive formation of each type of fine and coarse pores.

[0121] The choice of inorganic particles to provide the fine porosity as interstices resulting from the packing of the particles can also influence the ratio of coarse to fine pore size. For example, in contrast to Examples 3-7 that used a combination of diatomaceous earth and talc, Examples 8-15 used diatomaceous earth in combination with different secondaryinorganic particles, such as phlogopite (Examples 8A / 8B and 12), fused silica (Examples 9 and 10), muscovite (Ex. 11), phlogopite (Ex. 12) and hollow glass microspheres (Examples 15 and 16).

[0122] Different types of diatomaceous earth were also used to assess the effect derived from different diatomaceous earth morphologies shown in FIGS. 4A and 4B. For example, Examples 3-11, 13, and 15-16 used the diatomaceous earth from FIG. 4A, while Examples 2 and 12 used the diatomaceous earth from FIG. 4B, and Example 14 used a combination of both types. FIGS. 7A-B illustrate differential intrusion versus pore size distribution as measured during mercury porosimetry testing for the fired ceramic monoliths of Ex. 8B (Diafil 525 type diatomaceous earth particles) and Ex. 12 (“Celtix” type diatomaceous earth particles), respectively. The Celtix type diatomaceous earth material (e.g., see example particles in FIG. 4B) has a larger volume of fine pores within its particles than the Diafil 525 type diatomaceous earth material (e.g., see example particles in FIG. 4A) and therefore, the relative volume of fine porosity is observed to be higher for the monolith made in accordance with Ex. 12 (FIG. 7B) using the Celtix type material than that made in accordance with Ex. 8B (FIG. 7A) with the Diafil type material.

[0123] Multimodal pore size distributions having more than two peaks can also be created, such as trimodal distributions or distributions with a greater number of peaks. For example, in Ex. 14, a composition was formed that was a combination of both Diafil 525 and Celtix type diatomaceous earth particles, each at 40 wt%, which was added to 15.5% kaolin clay and 4.5 wt% sintering aid (4 wt% boric acid and 0.5 wt% K2CO3), all with respect to 100% inorganics in the mixture. To the composition was added 20 wt% superaddition of cross-linked pea starch, as well as water and the indicated organics. The composition was extruded into a green honeycomb body and fired at 950 °C for 4 hours. FIG. 8A illustrates cumulative intrusion versus pore size diameter of the substrate formed, and FIG. 8B illustrates differential intrusion versus pore size diameter of a substrate. In FIG. 8B, three peaks can be seen at approximately 5 pm, 1.5 pm, and 0.4 pm. In this trimodal Example, the dividing point between the definition of “coarse porosity” and “fine porosity” is the inflection point closest to 1 pm shown by the arrow in FIG. 8A.

[0124] Example 16 was unique in that it developed a bi-modal pore distribution without the use of an added organic pore former. Without wishing to be bound by theory, it appears that the hollow interiors of the hollow glass microsphere component contributed significantly to the coarse peak, while the inherent porosity of the diatomaceous earth particles contributedto the fine peak. Thus, Ex. 16 provides one example where bum out of an organic pore former is not required to obtain a coarse peak in the pore size distribution. Due to the absence of pore former in Ex. 16, the inorganic particulate matter (diatomaceous earth, hollow glass microspheres, talc, and clay) accounting for between about 95-96% of the total dry solids in this example.

[0125] Additional monolithic substrates were made in accordance with the Examples of Tables 5-9, including various monolithic substrates that had high porosities (e.g., at least 50%) and monomodal pore size distributions with the vast majority or even up to 100% of the porosity contributed by pores within the 0.1 pm to 1 pm pore size range. Similarly to the Examples of Tables 1-4, other Examples below exhibited multimodal pore size distributions (e.g., via the inclusion of pore former in the corresponding batch mixture), but still exhibited high porosities with a significant portion of the total porosity, e.g., at least 20% of the total porosity, contributed by pores within the 0.1 pm to 1 pm pore size range.

[0126] The raw materials that were used in each Example of Tables 5-8 are in the first grouping of rows, with the raw materials generally arranged first with the inorganic particles, then the organics (binder and / or pore former), and lastly the liquid components (e.g., water and oil). The diatomaceous earth (interchangeably referred to as diatomite) utilized was of the Diafil 525 type diatomaceous earth powder (shown in FIG. 4A), the fused silica was of the Teco-Sil type ground fused silica powder, each commercially available from Imerys S.A. HGMS refers to a powder of hollow glass microspheres of a sodium / calcium borosilicate composition and a median particle (bead / sphere) diameter of about 10-25 pm, the pea starch was a crosslinked pea starch, MOx refers to an anti-oxidant containing mineral oil, and water refers to deionized water.

[0127] Following the raw materials, Tables 5-8 detail the conditions under which the monolithic substrates were fired and / or the properties, such as geometry, of the Examples. The “geometry” in the Tables indicates the approximate cell density in cells per square inch (cpsi) and the approximate or nominal thickness of the webs in the honeycomb structure in mils (thousandths of an inch). For example, a “200 / 12” geometry refers to a honeycomb body with an approximate cell density of 200 cells per square inch and an approximate wall thickness of about 12.0-12.9 mils). Where applicable, the firing temperature (“soak” temperature) used to create the monolithic substrate of the corresponding Example is indicated. All Examples were held at the indicated firing temperature for 4 hours before cooling to ambient room temperature.

[0128] Various physical properties are next shown in the tables. The shrinkage amount indicates the change in % from the extruded diameter of the green part to the final diameter of the resulting fired article. The coefficient of thermal expansion as measured from RT-500°C. The cristobalite level in each example is reported as measured via Rietveld analysis in the honeycomb article after firing. The next three rows provide the vol% porosity, bulk density, and median pore diameter for the material (thus, excluding the channels) of each Example as measured by mercury intrusion. The modulus of rupture (MOR) is reported as measured by a 4-point bend strength test. The closed frontal area (or CFA) of the honeycomb body is reported in % as defined by the geometry of each example. The normalized MOR value corresponds to aforementioned MOR value divided by the CFA to mitigate the impact of different geometries of the honeycomb structures. The elastic modulus (E-modulus) as measured at room temperature is provided for some Examples.

[0129] To produce each honeycomb body, the dry ingredients for each Example were mixed in a Littleford mixer, followed by injection of the wet ingredients and a wet mix cycle. The wet mixed ingredients were fed into a twin screw extruder where the mixture was plasticized and extruded through a honeycomb die to produce a cylindrical green honeycomb structure having a diameter of approximately 2 inches. The extruded honeycomb structure was sliced into 6-inch logs and dried in a microwave dryer. The dried logs were then fired at a heating rate of approximately 75°C / hr to the listed firing temperature for a time of 4 hours.

[0130] Table 5: Examples 18-23 of raw materials, firing conditions, and physical properties.

[0131] Examples 18-20 in Table 5 used either diatomaceous earth or a mixture of diatomaceous earth and fused silica as the source of amorphous silica, along with phlogopite mica as a sintering aid. The reported properties were produced between 850°C - 950°C, with moderate CTE values (from 15-30xl0-7oC-1) and no cristobalite was observed in any of Examples 18-20 at these temperatures. In Examples 21-23, hollow glass microspheres were used to assist as both a sintering aid and to provide some additional porosity. The reported properties of Examples 21-23 were achieved at soak temperatures between 700-750°C, with lower CTE values generally achieved by use of lesser amounts of the hollow glass microspheres (e.g., 10 wt% hollow glass microspheres produced the lowest CTE for Examples 5a and 5b in comparison to the relatively larger CTEs at 15 wt% HGMS in Examples 23a-23b and 20 wt% HGMS in Examples 21a-21b). Additionally, firing at the relatively higher temperature of 750°C in comparison to 700°C also generally resulted in an increase of the CTE. Without wishing to be bound by theory, it is believed that the greater amounts of the hollowglass microspheres, as well as the higher firing temperature, resulted in increased cristobalite formation, which in turn led to a corresponding increase in CTE.

[0132] Table 6: Examples 7-11 of raw materials, firing conditions, and physical properties.

[0133] Examples 24-26 are mixtures of diatomaceous earth and kaolin clay as the inorganic raw materials. In these Examples, no additional sintering aid was utilized and a range of desirable properties were achieved at firing temperatures between 850°C-950°C. In Examples 27-28, boric acid was added as a sintering aid, which includes Examples both with and without kaolin clay. Again, firing temperatures of 850°C-950°C were used to achieve the reported properties. It is noted that when the soak temperature was raised to 950°C for the boric acid containing Examples 27c and 28c, substantial amounts of cristobalite were produced, which had the effect of sharply increasing the CTE in comparison to the Examples 10 and 11 at lower firing temperatures (i.e., Examples 27a-27b and 28a-28b, respectively). While some sintering aids did appear to cause increases to the CTE of the honeycomb bodies when fired at higher temperatures, such a drastic increase was not seen in Examples having no sintering aid or a sintering aid other than boric acid.

[0134] For some of the Examples of Table 6, elastic moduli data is provided (see Examples 24b, 25b, 27b, 28b). For these Examples, strain tolerance is shown as the ratio of the MOR to the elastic modulus (in %). The strain tolerance represents the strain that the body can be put under before failure. The strain tolerance can be importantly to assess the thermomechanical performance of a body, as the strain tolerates relates to the thermal shock resistance of the body. More particularly, the thermal shock resistance is proportional to strain tolerance multiplied by the thermal expansion coefficient (CTE). Therefore, the higher the strain tolerance, the higher the thermal shock resistance for a given CTE. Considered alternatively, the higher the strain tolerance, the higher the CTE can be to reach a particular thermal shock limit. A representative strain tolerance for traditional cordierite honeycomb bodies used in exhaust aftertreatment are expected to be in the range of about 0.05%. Accordingly, the reported strain tolerances in the range of 0.13% to 0.19% in Table 6 indicates that the honeycomb bodies made in accordance with these Examples can accommodate relatively higher thermal expansion coefficients than traditional cordierite honeycombs (e.g., up to 20, 25, or even 30xl0-7oC-1) and still retain suitable thermal shock resistance.

[0135] In accordance with the description herein, the addition of a minor portion of kaolin clay (e.g., less than 20 wt%) can be useful as an aid to assist in improving the extrudability of the batch. To this end, the use of kaolin clay or other extrusion aid material may be sufficient in some batches to enable satisfactory extrudability without the need for oils or other lubricants. For example, Examples 25 and 26 differed only in the use of MOx in that the batch mixtures to make the honeycombs of Example 25 contained a 5 wt% superaddition of MOx, while the batch mixtures to make the honeycombs of Example 26 did not have any MOx. It was observed that while the MOx addition was useful for adjusting rheology to assist in extrusion of the batch, the honeycombs of Example 26, which could be produced without MOx, had a generally higher strength.

[0136] Table 7: Examples 29-35 of raw materials, firing conditions, and physical properties.

[0137] Examples 29-35 are mixtures of diatomaceous earth and kaolin clay, and optionally fused silica, as well as up to one of titania, gamma alumina, feldspar, or calcium carbonate as a sintering aid. Some of these Examples included pea starch as a pore former to assess the ability to achieve even higher porosities (e.g., greater than 55% or even 60% porosity). In the case of Example 32, ahigh loading of starch (30 wt% as superaddition) was used which resulted in correspondingly low strength when fired to 850°C (Example 32a), but the strength increased significantly due to further sintering when fired at 950°C (Example 32b). Although not as drastic as the CTE increases seen in Examples 27c and 28c, the 5% calcium carbonate addition for Example 35 did result in a significant CTE increase when fired to 950°C (Example 18b) in comparison to when fired to 850°C (Example 18a).

[0138] Table 8: Examples 36-40 of raw materials, firing conditions, and physical properties.

[0139] Examples 36-40 are mixtures of diatomaceous earth, kaolin clay, fused silica and various sintering aids. All Examples of Table 8 produced advantageous combinations of good strength, high porosity, and low CTE, with the exception of Example 37b, which had a relatively high CTE (> 30 xlO-7oC-1) due to formation of cristobalite when fired to 950°C.

[0140] As a further experiment, Table 9 represents Examples corresponding to honeycomb bodies were extruded at larger sizes than Examples 18-40 in Tables 5-8. As the size increases, honeycomb bodies may become generally more susceptible to cracking (e.g., a higher proportion of honeycomb bodies in a manufactured population will experience cracking), such as during or after firing. Accordingly, Table 9 shows data with respect to honeycomb bodies that were formed as cylindrical bodies with a diameter of approximately 5.66 inches and an axial length of approximately 6 inches.

[0141] The Examples in Table 9 are arranged adjacently in pairs with a first Example in which cracking was observed and a second Example that has a substantially similar batch mixture but with an adjustment to include a sintering aid that eliminated the cracking. Forexample, Examples 41 and 42 were substantially similar, but with Example 41 comprising no sintering aid and Example 42 comprising 1 wt% potassium carbonate in exchange for a reduction of 1 wt% fused silica. Similarly, Examples {43 and 44}, {45 and 46}, {47 and 48}, and {49 and 50} form the aforementioned pairs.

[0142] Table 9: Examples 41-50 - 5.66”x6” cracking susceptibility evaluation

[0143] As summarized in Table 9, Examples 41-50 are mixtures of diatomaceous earth and kaolin clay, optionally fused silica, and optionally calcium carbonate, magnesium hydroxide, or potassium carbonate. After firing, the parts were inspected for firing cracks. For example, cracking can occur due to dimensional changes occurring during the firing cycle where thermal gradients exist within the parts causing strains. All Examples in Table 9 were fired at a soak temperature of 950°C for a period of 4 hours after ramping the temperature from room temperature to the soak temperature at a rate between 25°C / hour to 100°C / hour. The firing cycle was not optimized to reduce cracking so that the effect of the sintering aid on cracking susceptibility could be assessed. SEM images corresponding to the monolithic substrates formed in accordance with Examples 42, 44, and 50 are shown in FIGS. 9A-9B, 10A-10B, and 11A-1 IB, respectively.

[0144] From the compositions shown in Table 9, it can be seen that the addition of potassium was very effective in eliminating cracking in this experiment. Namely, potassium was provided in the form of potassium carbonate, which was added in very small amounts, of only 1 wt% to 2 wt%. In general, more potassium was usefill where high amounts of pore former was included(e.g., Examples 49 and 50) and when no fused silica were utilized (e.g., Examples 43 and 44). Comparable amounts of calcium carbonate (Example 30) and magnesium hydroxide (Example 45) without the potassium addition were not successful in eliminating cracking. While the potassium-containing sintering aid used was potassium carbonate, other potassium-containing materials such as carbonates, oxides, hydroxides, or nitrates of potassium could be utilized to provide a comparable amount of potassium. Without wishing to be bound be theory, it is thought that the addition of potassium allows for a low melting glass to form during the firing cycle which can relive stresses arising from thermal gradients.

[0145] The terms and expressions that have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the aspects of the present disclosure. Thus, it should be understood that although the present disclosure has been specifically described by specific aspects and optional features, modification and variation of the concepts herein disclosed may be resorted to by those of ordinary skill in the art, and that such modifications and variations are considered to be within the scope of aspects of the present invention.

Claims

CLAIMSWhat is claimed is:

1. A monolithic substrate comprising: a matrix of a glass-ceramic composite material defining a continuous interconnected pore structure, wherein the glass-ceramic composite material has a porosity of at least 48% by volume as determined by mercury intrusion porosimetry, and wherein at least 20% of the porosity is contributed by pores having a pore diameter between 0.1 pm and 1 pm, as determined by mercury intrusion porosimetry.

2. The monolithic substrate of claim 1, wherein at most 5% of the porosity, by volume, is contributed by pores having a pore diameter less than 0.1 pm, as determined by mercury intrusion porosimetry.

3. The monolithic substrate of any one of claims 1-2, wherein at most 3% of the porosity, by volume, is contributed by pores having a pore diameter less than 0.1 pm, as determined by mercury intrusion porosimetry.

4. The monolithic substrate of any one of claims 1-3, wherein at most 1% of the porosity, by volume, is contributed by pores having a pore diameter less than 0.1 pm, as determined by mercury intrusion porosimetry.

5. The monolithic substrate of any one of claims 1-4, wherein at most 5% of the porosity, by volume, is contributed by pores having a pore diameter less than 0.05 pm, as determined by mercury intrusion porosimetry.

6. The monolithic substrate of any one of claims 1-5, wherein a median pore size of the interconnected pore structure is between 0.1 pm and 1 pm, as determined by mercury intrusion porosimetry.

7. The monolithic substrate of any one of claims 1-6, wherein a median pore size of the interconnected pore structure is less than 1 pm, as determined by mercury intrusion porosimetry.

8. The monolithic substrate of any one of claims 1-7, wherein a median pore size of the interconnected pore structure is less than 1 pm, as determined by mercury intrusion porosimetry.

9. The monolithic substrate of any one of claims 1-8, wherein the porosity is at least 50% by volume, as determined by mercury intrusion porosimetry.

10. The monolithic substrate of any one of claims 1-9, wherein the porosity is at least 50% by volume, as determined by mercury intrusion porosimetry.

11. The monolithic substrate of any one of claims 1-10, wherein the porosity is at least 55% by volume, as determined by mercury intrusion porosimetry.

12. The monolithic substrate of any one of claims 1-11, wherein the porosity is at least 48% to 75% by volume, as determined by mercury intrusion porosimetry.

13. The monolithic substrate of any one of claims 1-12, wherein the porosity is at least 50% to 75% by volume, as determined by mercury intrusion porosimetry.

14. The monolithic substrate of any one of claims 1-13, wherein the interconnected pore structure has a multimodal pore size distribution.

15. The monolithic substrate of claim 14, wherein the multimodal pore size distribution is comprises a first differential intrusion peak at a first pore diameter between 0.1 pm and 1 pm and a second differential intrusion peak at a second pore diameter between 1.5 pm and 30 pm.

16. The monolithic substrate of claim 15, wherein the second differential intrusion peak is at a pore diameter of at least 5 pm.

17. The monolithic substrate of any one of claims 1-16, wherein at least 50% of the porosity is contributed by pores having a pore diameter between 0.1 pm and 1 pm, as determined by mercury intrusion porosimetry.

18. The monolithic substrate of any one of claims 1-17, wherein at least 80% ofthe porosity is contributed by pores having a pore diameter between 0.1 pm and 1 pm, as determined by mercury intrusion porosimetry.

19. The monolithic substrate of any one of claims 1-18, wherein the interconnected pore structure has a monomodal pore size distribution with a single differential intrusion peak.

20. The monolithic substrate of any one of claims 1-19, wherein the glass-ceramic composite material comprises at least 50 wt% amorphous silica.

21. The monolithic substrate of any one of claims 1-20, wherein the glass-ceramic composite material comprises at least 70 wt% amorphous silica.

22. The monolithic substrate of any one of claims 1-21, wherein the glass-ceramic composite material comprises at least 90 wt% amorphous silica.

23. The monolithic substrate of any one of claims 1-22, wherein the glass-ceramic composite material comprises at least 50% sintered diatomaceous particles.

24. The monolithic substrate of any one of claims 1-23, wherein the glass-ceramic composite material comprises at least 70 wt% sintered diatomaceous earth particles.

25. The monolithic substrate of any one of claims 1-24, wherein the glass-ceramic composite material comprises at least 90 wt% sintered diatomaceous earth particles.

26. The monolithic substrate of any one of claims 1-25, wherein the glass-ceramic composite material comprises at least 5 wt% sintered fused silica particles.

27. The monolithic substrate of any one of claims 1-26, wherein the glass-ceramic composite material comprises at least 10 wt% sintered fused silica particles.

28. The monolithic substrate of any one of claims 1-27, wherein the glass-ceramic composite material comprises at least 15 wt% sintered fused silica particles.

29. The monolithic substrate of any one of claims 1-28, wherein the glass-ceramic composite material comprises at least 5% sintered aluminosilicate particles.

30. The monolithic substrate of any one of claims 1-29, wherein the glass-ceramic composite material comprises at least 10% sintered aluminosilicate particles.

31. The monolithic substrate of any one of claims 1-30, wherein the glass-ceramic composite material comprises at least 5% sintered clay mineral particles.

32. The monolithic substrate of any one of claims 1-31, wherein the glass-ceramic composite material comprises at least 10% sintered clay mineral particles.

33. The monolithic substrate of any one of claims 1-32, wherein the monolithic substrate has a honeycomb configuration comprising an array of intersecting walls defining channels extending axially through the monolithic substrate.

34. The monolithic substrate of any one of claims 1-33, wherein a bulk density of the monolithic substrate is at most 1.1 g / cm3.

35. The monolithic substrate of any one of claims 1-34, wherein a bulk density of the monolithic substrate is at most 1.05 g / cm3.

36. The monolithic substrate of any one of claims 1-35, wherein a bulk density of the monolithic substrate is at most 1 g / cm3.

37. The monolithic substrate of any one of claims 1-36, wherein a bulk density of the monolithic substrate is from 0.6 g / cm3to 1.1 g / cm3.

38. The monolithic substrate of any one of claims 1-37, wherein an apparent density of the glass-ceramic composite material is at most 2.5 g / cm3.

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