Low mass amorphous silica articles and methods of manufacture

Abstract

An amorphous silica article and method of manufacturing. The amorphous silica article includes an array of intersecting walls defining a plurality of channels extending axially through the article. The walls are comprised of a porous sintered glass and / or ceramic material that comprises at least 50 wt% diatomaceous earth. Articles having low bulk density and high porosity with a small median pore size are also provided.

Description

Low MASS MORPHOUS SILICA RTICLES AND METHODS OF MANUFACTURECross-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 / 522691 filed on June 22, 2023, the content of which is relied upon and incorporated herein by reference in its entirety.Field

[0002] This disclosure relates to low mass amorphous silica articles, and in particular where a source of the amorphous silica includes diatomaceous earth, and even more particularly where the article is coated by and / or impregnated with an active material, such as a catalyst or sorbent.BACKGROUND

[0003] Honeycomb bodies are useful as high surface area substrates for a variety of applications. For example, honeycomb bodies can be useful as a catalyst carrier, such for the exhaust aftertreatment system of an internal combustion automobile. Cordierite has found widespread use in automotive and diesel emissions control as a catalyst carrier and also for gasoline and diesel particulate filters due at least in part to the good thermomechanical properties of cordierite (e.g., high thermal shock resistance, low coefficient of thermal expansion), which enables cordierite honeycombs survive very high temperatures and temperature gradients experienced by in exhaust aftertreatment components systems.

[0004] However, the production of cordierite is energy intensive, typically requiring firing temperatures of at least 1300°C-1400°C. Additionally, honeycomb bodies are potentially relevant to a variety of applications both within and outside of exhaust aftertreatment, for which cordierite or other traditional materials may not be optimal. Accordingly, there remains a perpetual opportunity for new materials that can be cost effectively manufactured and which provide beneficial properties to a number of potential applications.SUMMARY

[0005] Disclosed herein are various articles comprising a porous, sintered amorphous silica material.

[0006] It is to be understood that both the foregoing general description and the following detailed description are merely exemplary, and are intended to provide an overview or framework to understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiment(s), and together with the description, serve to explain principles and operation of the various embodiments.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] 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.

[0008] FIGS 2A and 2B are scanning electron microscope (SEM) micrographs of examples of different diatomaceous earth particles that can be utilized to form the amorphous silica articles disclosed herein.

[0009] FIGS. 3A and 3B are SEM micrographs at two different magnifications of the polished cross-section of an article formed in accordance with Example 25 disclosed in Table 5 herein.

[0010] FIGS. 4A and 4B are SEM micrographs at two different magnifications of a wall surface of an article formed in accordance with Example 27 disclosed in Table 5 herein.

[0011] FIGS. 5A and 5B are SEM micrographs at two different magnifications of a polished cross-section of a wall of an article formed in accordance with Example 18 disclosed herein.DETAILED DESCRIPTION

[0012] Reference will now be made in detail to exemplary embodiments which are illustrated in the accompanying drawings. Whenever possible, the same reference numeralswill be used throughout the drawings to refer to the same or like parts. The components in the drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the exemplary embodiments.

[0013] Numerical values, including endpoints of ranges, can be expressed herein as approximations preceded by the term “about,” “approximately,” or the like. In such cases, other embodiments include the particular numerical values. Regardless of whether a numerical value is expressed as an approximation, two embodiments are included in this disclosure: one expressed as an approximation, and another not expressed as an approximation. It will be further understood that an endpoint of each range is significant both in relation to another endpoint, and independently of another endpoint.

[0014] Articles described herein may be useful as a high surface area support for a catalyst (e.g., for exhaust aftertreatment or other purpose), sorbent (e.g., for the carbon dioxide capture or other purpose), or other active or functional material (e.g., for a selected treatment of a fluid flow). The amorphous silica bodies disclosed herein can advantageously provide articles having attractive physical properties such as a low coefficient of thermal expansion (CTE), good strength, and low mass, e.g., exhibited by high porosity and / or low bulk density, and / or while being manufacturable at low firing temperatures. For example, the diatomaceous earthbased amorphous silica bodies disclosed herein may find particular relevance when used as a catalyst carrier substrate for selective catalytic reduction (SCR) of nitrogen oxides (NOx) from emissions from diesel engines where temperatures are high, albeit not as high as components positioned at more upstream positions in an exhaust aftertreatment system.

[0015] A low thermal expansion coefficient is an important feature for a honeycomb catalyst carrier, such as an SCR catalyst carrier. For example, exhaust aftertreatment devices must possess a high thermal shock resistance in order to withstand severe thermal gradients without cracking. In addition, it is important that exhaust aftertreatment device has a low bulk density (low thermal mass) and low heat capacity so that it can be heated quickly, e.g., to reach an effective temperature of the catalyst being carried in a short period of time. For example, the reduction of nitrous oxides (NOx) by an SCR catalyst requires elevated temperatures for the catalyst to drive the reduction reaction. Therefore, the faster the device heats up to the “light- off temperature” (temperature at which the catalyst is catalytically active), the more the emission of NOx is reduced.

[0016] Accordingly, there is an opportunity for non-cordierite materials that offer lower temperature firing, new microstructural arrangements, and other unique combinations of properties. The bodies disclosed herein have a low mass (e.g., high porosity and / or low bulk density) and low heat capacity which can benefit a number of applications by having a fast light off (heat up) time and / or low energy input necessary to reach a desired temperature. Bodies disclosed herein exhibit low thermal expansion coefficients that meet thermal shock resistance requirements. It also has a beneficial combination of low bulk density and high strength. In addition, the body can be manufactured at reduced cost and energy expenditure, due to lower firing temperatures.

[0017] In various aspects, disclosed herein are articles that comprises a major component (greater than or equal to 50 wt%) of amorphous silica, and in some aspects at least 80 wt% amorphous silica, or more. One challenge presented by amorphous silica-based articles is the tendency of amorphous silica toward devitrification at elevated temperatures (e.g., greater than about 1000°C) where crystallization of certain ceramic phases can occur. In particular, the formation of cristobalite may correspondingly result in large increases in the coefficient of thermal expansion of the fired material. Even without significant formation of cristobalite, CTE generally increases at high firing temperatures. In addition, it is difficult to sinter amorphous silica particles, since the glass transition of temperature, Tg, of silica is very high (i.e., greater than 1200°C). However, at these temperatures, increases to CTE are expected and conversion to cristobalite occurs rapidly.

[0018] As described herein, the use of diatomaceous earth as the major source of amorphous silica has been found to be capable of delivering unique combinations of desirable properties including high porosity, low bulk density, high strength, small median pore size, and low firing temperatures. For example, the properties disclosed herein at achievable at sintering temperatures less than 1100°C, or even less than 1000°C, such as between 700°C and 950°C. Further, the aforementioned high porosities are achievable, e.g., porosities of greater than 40% or even 50%, without the addition of any pore former particles, e.g., pyrolyzable pore former particles, and with even higher porosities achievable when pore former is added, e.g., greater than 60% porosity.

[0019] The material of the articles disclosed herein may be referred to as a “glass and / or ceramic containing material” in that the material comprises some combination of one or more glass, ceramic, or glass-ceramic constituents. For example, the amorphous silica, and inparticular diatomaceous earth, can be categorized as a glass, but one or more ceramic phases may form during sintering. For example, some degree of crystallization may occur during firing, such at interfaces between the amorphous silica and / or inorganic filler particles. In addition, the optionally included inorganic fillers (e.g., inorganic oxides or ceramic precursors, such as clay) may also convert into and / or otherwise contribute to the formation of ceramic phases during firing. Accordingly, the resulting materials may comprise a majority of a glass material in the form of amorphous silica, but may have also undergone some degree of crystallization, resulting in the articles to comprise some amount of ceramic and / or glassceramic material.

[0020] The articles disclosed herein can be, for example, honeycomb bodies, which may interchangeably be referred to herein as “honeycomb bodies”, “honeycomb articles” or simply “honeycombs”. In addition, honeycombs may be referred to as “cellular” in that such honeycomb bodies comprise an intersecting array of walls (of the glass, ceramic, and / or glassceramic containing material), where groupings of the walls (each a “cell”) define channels extending axially through the honeycomb bodies. For example, FIG. 1 illustrates a honeycomb body (article) 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, sintered amorphous materials described herein.

[0021] At least a portion of the amorphous silica used to create the porous, amorphous silica materials of this disclosure is provided by diatomaceous earth, which may be alternatively referred to or known as diatomite or kieselguhr. The body may also comprise a material that aids in the sintering of the body at elevated temperatures, referred to herein as a sintering aid. Optionally, the body may also contain an inorganic filler that assists in the manufacture (e.g., aids in extrusion) or properties of the honeycomb body (e.g., that contributes to a low CTE), such as kaolin clay. In addition, further organic binders, lubricants, pore formers, or other materials may be utilized to assist during manufacture, but are absent or removed (e.g., burned out) from the resulting article during firing as described herein.

[0022] SEM micrographs of examples of diatomaceous earth particles are shown in FIG. 2A and 2B. FIGS. 3A-3B are SEM micrographs of a polished cross-section of a wall of an article comprising a porous, sintered amorphous silica material in accordance with Example 25 at two different magnifications (200x and lOOOx). FIGS. 4A-4B are SEM micrographs of the outer surface of a wall of an article comprising a porous, sintered amorphous silica material in accordance with Example 27 at two different magnifications (500x and lOOOx). FIGS. 5 A and 5B are SEM micrographs of a polished cross-section of a wall of an article comprising a porous, sintered amorphous silica material having a plurality of larger pores created by a pore former addition in the batch akin to Example 18.

[0023] According to aspects described herein, the body has a low thermal mass and sufficient mechanical properties for a variety of applications, such as in an exhaust aftertreatment system for a combustion engine. The bodies described herein can be characterized by a combination of one or more of a low coefficient of thermal expansion (e.g., less than 30 x 10'7°C'1from RT-500°C), a high porosity (e.g., at least 40% by volume), a low bulk density (at most I .2g / cm3), a small median pore size (e.g., less than 1.1 pm) and / or a high material strength (e.g., comparable or even greater than that which can be achieved in cordierite at an equivalent porosity and geometry). For example, in some aspects, the articles disclosed herein exhibit a unique combination of high porosity (e.g., at least 50% by volume), while having a particularly small median pore size (e.g., less than 1.1 pm). Additionally, according to the methods disclosed herein, combinations of one or more of the aforementioned properties, such as high strength, low CTE, and / or low mass, can be achieved at comparatively low firing temperatures, such as top soak firing temperatures of less than 1000°C, such as at most about 950°C.

[0024] Accordingly, also provided herein are methods to produce porous amorphous silica articles, and in particular, diatomaceous earth-based amorphous silica articles. The articles can be produced by combining diatomaceous earth powder, optionally with a second source of amorphous silica, such as a ground fused silica powder. A filler material can also optionally be included that aids in the extrusion process or that contributes to a low thermal expansion coefficient (e.g., clay or cordierite), and also optionally with a suitable sintering aid containing low temperature glass formers such as borates, phosphates, or flux materials such as alkali or alkaline earth oxides, carbonates, hydroxides or transition metal oxides hydroxides, or carbonates, or alkali and alkaline earth silicates or alumino-silicates or combinations of any of these. In some cases, pore forming powders may also be added to the mixture to increase theporosity of the fired body. These may include amorphous or crystalline sources of carbon, or hydrocarbon materials such as starches (e.g., pea, com, potato, or other vegetable starches), flours (e.g., nut shell flours), synthetic polymers, and other pyrolyzable materials. These ingredients are combined with a suitable binder, such as methylcellulose, and extrusion vehicle such as water. The mixture can be extruded as a honeycomb structure and then cut and dried to form green honeycomb bodies. The green bodies are then fired to temperatures sufficient to pyrolyze or bum off the binders and pore formers, if present, and to sinter the body to achieve the desired strength.

[0025] Various aspects of the present disclosure provide articles made of a glass and / or ceramic material. The articles described herein may be referred to, or considered, as monoliths or as monolithic in nature, in that they are formed as a continuous structure that has been sintered together. However, due to the raw materials and relatively low firing temperatures selected, the articles described herein resemble an agglomeration or aggregation of particles sintered together, which differs from cordierite or other ceramic articles that are fully or nearly fully reacted into a relatively homogenous arrangement of one or more ceramic phases. That is, while conventional honeycomb bodies (e.g., cordierite bodies) may be formed by the full or nearly full reaction of ceramic precursors at very high temperature, the bodies described herein result from the sintering together of particles at relatively lower temperature without significant conversion or reaction into ceramic phases. For example, the firing temperatures of the methods described herein are low enough that the shape, structure, and inherent porosity of the diatomaceous earth particles are substantially retained even after firing.

[0026] The glass and / or ceramic material can include an interconnected pore structure that comprises the inherent or natural porosity of the diatomaceous particles. These natural or inherent pores of diatomaceous particles can have a median particle size of less than 1 micron. Unless stated otherwise, the median pore size, or median pore diameter, for a given type of pore can be determined as an assumed spherical median pore diameter determined via mercury porosimetry. Additional porosity may result from the voids or interstices between particles that result from the incomplete packing of the diatomaceous earth and / or other inorganic particles, which interstices remain after the particles are sintered together. The pores formed by interstices can be up to a few microns (e.g., less than 5 pm, such as from 1 pm to 5 pm). Additionally, even larger pores can be created by the use of a pore former, e.g., starch or other particles that are burned out during firing, for example, pore former having a size from about10 pm to 50 pm. The total pore volume of the amorphous silica materials described herein can be greater than or equal to 40% by volume as determined by mercury porosimetry, greater than or equal to 50% by volume, greater than or equal to 55% by volume, or even greater than 60% by volume. The articles disclosed herein can have a monomodal pore size distribution, a bimodal pore size distribution, or a higher order polymodal pore size distribution. Unless stated otherwise, porosity can be determined as a percentage by volume that is calculated via mercury porosimetry. In particular, ASTM D6761-07 can be utilized to determine the porosity.

[0027] It has been found that the porous amorphous silica bodies described herein are particularly advantageous when used as a substrate to which an active material is applied, such as to the surfaces of the walls of the articles described herein and / or within the pore structure of the porous sintered glass and / or ceramic materials described herein. That is, the interconnected porous structures resulting from the sintered diatomaceous earth-based articles disclosed herein enable the articles to be advantageously loaded with a significant amount of active material while also maintaining good kinetics for the active material even when so loaded at high levels of the active material. For example, the active material, such as a sorbent, can be loaded into the article in an amount of at least 75 grams of active material per liter occupied by the article (g / L), at least 80 g / L, at least 85 g / L, at least 90 g / L, at least 95 g / L, or even at least 100 g / L. In particular embodiments, the active material is a liquid, e.g., a liquid amine such as polyethyleneimine, and the interconnected pore networks of the porous diatomaceous earth based articles described herein enables the articles to exhibit resistance to leaching out of the liquid (i.e., retention of the liquid) during temperature and / or steam cycling (e.g., during carbon dioxide adsorb and desorb cycling), such as via capillary forces that hold the liquid in the pores.

[0028] To this end, the articles disclosed herein can comprise a particle deposition or coating of an active material that is separate from the base material of the article, e.g., is not sintered to the base material and / or is added in a separate manufacturing step after firing the article to sinter the amorphous silica particles together to form the article. The particle deposition or coating can include any suitable material, such as a sorbent (e.g., a sorbent that adsorbs and desorbs CO2, such as a liquid amine, amine resin, metal organic framework, zeolite, or carbonate), a catalyst (e.g., a three-way catalyst, an SCR catalyst), or a combination thereof. The particle deposition or coating of active material can be continuously (e.g., uniformly across or throughout the article) or discontinuously (e.g., non-uniformly) deposited.

[0029] As described herein, the amorphous silica-based glass and / or ceramic material of the article can have a low bulk density. Bulk density as used herein refers to the bulk density of the material itself, and not to the article as a whole. That is, when arranged as a honeycomb body the bulk density refers to the mass of the body divided by the total volume that the material of the body occupies, which can be determined as a sum of the particle / sintered material volume, inter-particle void (e.g., interstice) volume, and internal pore volume (e.g., the natural or inherent porosity of the diatomaceous earth particles), but does not include 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). Accordingly, the total volume that a honeycomb body occupies can be defined as the portions of the substrate when viewed from a longitudinal end of the substrate that is considered to be closed frontal area (CFA) versus those of the 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 form of the substrate, while the CFA corresponds to the remaining portions occupied by the material of intersecting walls.

[0030] For example, the amorphous silica material of the articles herein can have a bulk density of less than or equal to 1.2 g / cm3, less than or equal to 1.1 g / cm3, less than or equal to 1.0 g / cm3, less than or equal to 0.9 g / cm3, or even less than or equal to 0.8 g / cm3, such as low as 0.75 g / cm3, 0.74 g / cm3, 0.73 g / cm3, 0.72 g / cm3, 0.71 g / cm3, or even 0.7 g / cm3, including ranges that include these values as end points, such as from 0.72 g / cm3to 1.2 g / cm3, from 0.72 g / cm3to 1.1 g / cm3, from 0.72 g / cm3to 1.0 g / cm3, from 0.72 g / cm3to 0.9 g / cm3, from 0.72 g / cm3to 0.8 g / cm3, or even from 0.7 g / cm3to 1.2 g / cm3, from 0.7 g / cm3to 1. 1 g / cm3, from 0.7 g / cm3to 1.0 g / cm3, from 0.7 g / cm3to 0.9 g / cm3, or from 0.7 g / cm3to 0.8 g / cm3.

[0031] The amorphous silica-based material of the articles herein can have a total porosity, as determined via mercury porosimetry of at least 40%, at least 50%, at least 55%, or least 60%, or even at least 65%, such as up to 70% or more, including ranges including these values as end points, such as from 40% to 70%, from 50% to 70%, from 55% to 70%, from 60% to 70%, from 40% to 65%, from 50% to 65%, from 55% to 65%, or from 60% to 65%.

[0032] Due to the high proportion of diatomaceous earth particles and / or low firing temperatures, the median pore size of the amorphous silica-based materials of the articles herein can be particularly small, such as less than one micron even when a large amount of pore former is included (e.g., up to 30 wt% as superaddition). For example, the median poresize of the amorphous silica-based material of the articles herein can have a size of at most 1. 1 pm, at most 1 pm, at most 0.9 pm, at most 0.8 pm, at most 0.7 pm, at most 0.6 pm, at most 0.5 pm, at most 0.4 pm, at most 0.3 pm, at most 0.2 pm, such as low as 0.1 pm, including ranges having these values as endpoints, such as from 0.2 pm to 1.1 pm, from 0.2 pm to 1.0 pm, from 0.2 pm to 0.9 pm, from 0.2 pm to 0.8 pm, from 0.2 pm to 0.7 pm, from 0.2 pm to 0.6 pm, from 0.2 pm to 0.5 pm, from 0.2 pm to 0.4 pm, from 0.2 pm to 0.3 pm, or from 0.1 pm to 1.1 pm, from 0.1 pm to 1.0 pm, from 0.1 pm to 0.9 pm, from 0.1 pm to 0.8 pm, from 0.1 pm to 0.7 pm, from 0. 1 pm to 0.6 pm, from 0. 1 pm to 0.5 pm, from 0.1 pm to 0.4 pm, from 0. 1 pm to 0.3 pm, or even from 0.1 pm to 0.2 pm.

[0033] The articles disclosed herein can have a suitable flexural strength, or modulus of rupture (MOR) determined by a 4-point bend test, such as performed per ASTM-D6272. For ease of comparison of honeycomb bodies of different geometries, the MOR determined by the flexural strength test can be normalized by the CFA of the honeycomb body. For example, the honeycomb body can have a normalized strength in a 4-point bend test of the monolithic substrate normalized by the CFA of the monolithic substrate (i.e., MOR divided by the CFA of the monolithic substrate, given as a percentage) of greater than 500 psi, or even greater than 1000 psi, greater than 1500 psi, greater than 2000 psi, such as up to 5000 psi ormore, including ranges having these values as endpoints, such as from 500 psi to 2000 psi, from 1000 psi to 2000 psi, from 1500 psi to 2000 psi, from 500 psi to 2500 psi, from 1000 psi to 2500 psi, from 1500 psi to 2500 psi, from 500 psi to 5000 psi, from 1000 psi to 5000 psi, or from 1500 psi to 5000 psi.

[0034] In various aspects, article is arranged as a honeycomb body (e.g., via extrusion through a honeycomb extrusion die) that comprises an intersecting matrix or array of walls of the amorphous silica-based material that form a plurality of cells that define parallel channels running axially or longitudinally through the honeycomb body. The honeycomb body 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 and corresponding channels can have any suitable profile or shape, such as a circle, oval, square, rectangle, hexagon, triangle, polygon, or irregular shape. In FIG. 1, the honeycomb body 100 has a circular circumferential shape (is arranged as a cylinder) with square-shaped cells. The use of a honeycomb form can advantageously result in a lowerpressure 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).

[0035] When arranged as a honeycomb body, the articles herein can include any suitable number of cells per square inch (cpsi), 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 can 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.

[0036] The articles herein can optionally include a particle deposition or coating, such as a catalyst, a sorbent that adsorbs and desorbs CO2, or some other functional material, or a combination thereof. In various aspects, the particle deposition or coating can be directly adhered to the amorphous silica-based material, wherein the monolithic substrate is free of an intervening bonding layer between the particle deposition or coating and the amorphous silica- based material. However, in various aspects, the article can include an intermediary or bonding layer that assists in providing the particle deposition or coating onto the article. For example, the bonding layer can be or comprise high surface area particles, such as gamma alumina, zeolite, activated carbon, or a combination thereof. A coating that includes the sorbent can be the sorbent or can include one or more other components. A coating that includes a catalyst can be 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.

[0037] The articles described herein can be formed by preparing a raw material mixture (or interchangeably a “batch composition” or “batch mixture”) and then forming the mixture into the desired shape of the article, such as via extrusion. The extruded body can be cut to length and / or dried to form green bodies of the batch mixture. The green bodies are then fired in accordance with the disclosure herein to form the amorphous silica-based material.

[0038] The diatomaceous earth particle powder can have any suitable particle diameter, such as a median particle diameter of about 5 pm to 20 pm. As shown in FIG. 2A, the diatomaceous earth particles can be generally cylindrical, having a length at least equal to the diameter of the particle, or as shown in FIG. 2B the diatomaceous earth particles can be disc-like, having a length of only about 1 micron to 3 microns. Other types of diatomaceous earth are possible. In some aspects, the diatomaceous earth is at least 50 wt% of the batch mixture, with respect to total inorganics in the batch mixture, or even at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, or even at least 95 wt%, such as from 50 wt% to 95 wt%.

[0039] The inorganic oxide filler material can have any suitable particle diameter, such as smaller than the median particle size of the diatomaceous earth particles so as to fill in and around the diatomaceous earth particles. For example, the filler material can be a powder having a median particle diameter of 0.2 microns to 10 microns, such as from 1 micron to 5 microns. The inorganic oxide filler material can comprise kaolin clay, cordierite, or another aluminosilicate that facilitates extrusion, forming, and / or sintering.

[0040] Since the liquid component and organics in an batch mixture are expected to bum out or otherwise be removed during drying and / or firing, and by selecting firing conditions that sinter the particles together while preserving the diatomaceous particles, natural or inherent porosity of the diatomaceous particles, and interstices between particles 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 particulate material in the resulting sintered structure. 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 reflect the approximate amount of the corresponding material in the resulting porous, sintered amorphous silica material after firing. 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 about 50 wt% of diatomaceous earth in the resulting sintered amorphous silica material (after the liquid component and organic components are removed during drying and firing).

[0041] 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 4wt% to 10 wt%. 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 10 wt% to 40 wt% superaddition.

[0042] 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 alkaline earth silicate), an alumino-silicate, Fe2C>3, 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. In particular, sintering aids that comprise 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 5 wt%, such as from 1 wt% to 5 wt%, with respect to 100% inorganics in the batch mixture.

[0043] The batch mixture can further comprise a pore-forming material for forming additional pores in the porous, sintered amorphous silica material. The pore-forming material can include any suitable material that degrades 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 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. The pore forming material can form any suitable proportion of the batch mixture, such as 5 wt% to 45 wt% as a superaddition with respect to 100% inorganics in the batch mixture, or from 10 wt% to 30 wt%, at least 10 wt%, at least 20 wt%, or even at least 30 wt%. In various aspects, the extrudable composition can be substantially free of the poreforming material and still have a porosity of at least 40% or even at least 50% by volume, such as 0 wt% pore-forming material in the batch mixture, or less than or equal to 5 wt%, 4 wt%, 3 wt%, 2 wt%, 1 wt%.

[0044] The batch mixture can further include one or more liquid components or vehicles, such as water or other aqueous liquid. The liquid component can form any suitable proportion of the batch mixture, such as 50 wt% to 80 wt% as a super addition with respect to 100% of a total weight of dry solids in the batch mixture, with a greater proportion of water needed based on the amount of diatomaceous earth particles in the batch or other particles that contribute a high natural or inherent porosity.

[0045] 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 the diatomaceous earth particles together (e.g., with assistance of the sintering aid) and that degrades and / or pyrolyzes any poreforming materials. 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 sintering (and / or some degree of reaction) of the diatomaceous earth and / or sintering aid such as a firing temperature of less than 1000°C, up to 950°C, or in a range from 700 °C to 950 °C. The firing can include firing for a duration of (e.g., maintaining the firing temperature for a duration of) 1 h to 24 h, such as from about or 2h to lOh.

[0046] As described herein, the firing temperature can be selected such that the diatomaceous earth particles are sintered together as a result of the firing process (e.g., as assisted by the sintering aid), but without significant reaction of the particles into one or more ceramic phases. That is, the diatomaceous earth 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. For example, as shown in the examples of FIGS. 3A to 5B, the individual diatomaceous earth particles largely retain their original shape and size, as well as their natural porosity even after being fired into the continuous sintered material. As a result, the amorphous silica materials disclosed herein (and as exhibited by the examples of FIGS. 3A to 5B) can each be described as an agglomerate of sintered particles.

[0047] 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

[0048] Various aspects will be further clarified by the following examples. Tables 1-4 below each show a list of example honeycomb substrates that were produced with the indicated raw materials and the resulting honeycomb bodies measured for the reported physical properties under the indicated firing conditions. Examples that were made with the same raw material mixture are each provided with an Example number that shares the same base numeral, but with alphabetic suffixes (e.g., ‘a’, ‘b’, ‘c’) that correspond to different firing temperatures. Forexample, Examples la and lb were made from the same raw material mixture, but Example la was fired at 85O°C, while Example lb was fired at 900°C. For ease of discussion, reference herein to just the base numeral of an Example refers generally to all Examples having that base numeral. For example, reference to “Example 1” includes reference to both Example la and Example lb.

[0049] The raw materials that were used in each Example are in the first grouping of rows of each of Tables 1-4, with the raw materials generally arranged first with the inorganics, then the organics (binder and / or pore former), and lastly the liquid components (e.g., water and oil). The diatomaceous earth (diatomite) utilized was of the Diafil 525 type diatomaceous earth powder (shown in FIG. 2A), 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, mineral oil refers to an anti-oxidant containing mineral oil, and water refers to deionized water.

[0050] Following the raw materials, the row in the Tables for the geometry of the Examples indicates the approximate cell density in cells per square inch (cpsi) and the approximate thickness of the webs in the honeycomb structure in mils or thousandths of an inch (e.g., a 200 / 12 geometry thereby referring 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). The next row shows the firing temperature (“soak” temperature) used for each Example. All Examples were held at the indicated firing temperature for 4 hours before cooling to ambient room temperature.

[0051] 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 geometriesof the honeycomb structures. The elastic modulus (E-modulus) as measured at room temperature is provided for some Examples.

[0052] 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.

[0053] Table 1: Examples 1-6 of raw materials, firing conditions, and physical properties.

[0054] Examples 1 -3 in Table 1 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 1-3 atthese temperatures. In Examples 4-6, hollow glass microspheres were used to assist as both a sintering aid and to provide some additional porosity. The reported properties of Examples 4- 6 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 6a-6b and 20 wt% HGMS in Examples 4a-4b). 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 hollow glass microspheres, as well as the higher firing temperature, resulted in increased cristobalite formation, which in turn led to a corresponding increase in CTE.

[0055] Table 2: Examples 7-11 of raw materials, firing conditions, and physical properties.

[0056] Examples 7-9 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 Examples10-11, 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 10c and 11c, 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 lOa-lOb and 1 la-1 lb, 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.

[0057] For some of the Examples of Table 2, elastic moduli data is provided (see Examples 7b, 8b, 10b, 1 lb). 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 2 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.

[0058] 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 8 and 9 differed only in the use of mineral oil in that the batch mixtures to make the honeycombs of Example 8 contained a 5 wt% superaddition of mineral oil, while the batch mixtures to make the honeycombs of Example 9 did not have any mineral oil. It was observed that while the mineral oil addition was useful for adjusting rheology to assist inextrusion of the batch, the honeycombs of Example 9, which could be produced without mineral oil, had a generally higher strength.

[0059] Table 3: Examples 12-18 of raw materials, firing conditions, and physical properties.

[0060] Examples 12-18 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 15, a high loading of starch (30 wt% as superaddition) was used which resulted in correspondingly low strength when fired to 850°C (Example 15a), but the strength increased significantly due to further sintering when fired at 950°C (Example 15b). Although not as drastic as the CTE increases seen in Examples 10c and 11c, the 5% calcium carbonate additionfor Example 18 did result in a significant CTE increase when fired to 950°C (Example 18b) in comparison to when fired to 850°C (Example 18a).

[0061] Table 4: Examples 19-23 of raw materials, firing conditions, and physical properties.

[0062] Examples 19-23 are mixtures of diatomaceous earth, kaolin clay, fused silica and various sintering aids. All Examples of Table 4 produced advantageous combinations of good strength, high porosity, and low CTE, with the exception of Example 20b, which had a relatively high CTE (> 30 xlO-7oC-1) due to formation of cristobalite when fired to 950°C.

[0063] As a further experiment, Table 5 represents Examples corresponding to honeycomb bodies were extruded at larger sizes than Examples 1-23 in Tables 1-4. 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 5 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.

[0064] The Examples in Table 5 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. For example, Examples 24 and 25 were substantially similar, but with Example 24 comprising no sintering aid and Example 25 comprising 1 wt% potassium carbonate in exchange for a reduction of 1 wt% fused silica. Similarly, Examples 26 and 27, 28 and 29, 30 and 31, and 32 and 33 form the aforementioned pairs.

[0065] Table 5: Examples 24-33 - 5.66”x6” cracking susceptibility evaluation

[0066] As summarized in Table 5, Examples 24-33 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 5 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.

[0067] From the compositions shown in Table 5, it can be seen that the addition of potassium was very effective in eliminating cracking in this experiment. Namely, potassium was providedin the form of potassium carbonate, which was added in very small amounts, of only 1 wt% to 2 wt%. In general, more potassium was useful where high amounts of pore former was included (e.g., Examples 32 and 33) and when no fused silica were utilized (e.g., Examples 26 and 27). Comparable amounts of calcium carbonate (Example 30) and magnesium hydroxide (Example 28) 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.

[0068] In one experiment, representative samples made using the batch mixtures in accordance with Examples 18a and 22a, at a size of approximately 4.5-5 inch diameter and 10 inch axial length, were created, then loaded with polyethyleneimine, and tested with respect to their carbon capture performance. In particular, the performance was evaluated in a steambased temperature swing carbon capture system with respect to the equilibrium capacity in mmol of carbon dioxide captured per liter occupied by the article, and as sorbent efficiency in mmol of carbon dioxide captured per gram of sorbent. Overall, the sorbent loadings achieved were very high, the carbon capture performance was very good, and the tested samples did not appear to exhibit leaching out of the PEI after cycling. The relevant loadings and performance results are reflected in Table 6.

[0069] Table 6 - Properties and carbon capture performance of representative samples

[0070] It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the claimed subject matter.Accordingly, the claimed subject matter is not to be restricted except in light of the attached claims and their equivalents.

Claims

What is claimed is:1 . An amorphous silica article, comprising: an array of intersecting walls defining a plurality of channels extending axially through the article, wherein the walls are comprised of a porous sintered glass and / or ceramic material that comprises at least 50 wt% diatomaceous earth.

2. The article of claim 1, further comprising an active material on surfaces of the walls, within pores of the porous sintered glass and / or ceramic material, or both.

3. The article of claim 2, wherein the active material is a sorbent.

4. The article of claim 3, wherein the sorbent has selectivity for carbon dioxide.

5. The article of either of claims 3 or 4, wherein the sorbent is a liquid sorbent.

6. The article of any of claims 3-5, wherein the sorbent is loaded in an amount of at least75 grams of sorbent per liter occupied by the article.

7. The article of any one of claims 1-6, wherein the porous sintered glass and / or ceramic material comprises from 50 wt% to 95 wt% diatomaceous earth.

8. The article of any one of claims 1-7, wherein the porous sintered glass and / or ceramic material comprises at least 65 wt% diatomaceous earth.

9. The article of any one of claims 1-8, wherein the porous sintered glass and / or ceramic material comprises at least 80 wt% amorphous silica.

10. The article of any one of claims 1-9, wherein the porous sintered glass and / or ceramic material comprises at least 10 wt% fused silica in addition to the diatomaceous earth.

11. The article of any one of claims 1-10, wherein the porous sintered glass and / or ceramic material comprises at least 5 wt% of an inorganic oxide filler.

12. The article of claim 11, wherein the inorganic oxide filler comprises an aluminosilicate.

13. The article of claim 11, wherein the porous sintered glass and / or ceramic material comprises from 5 wt% to 25 wt% of the inorganic oxide filler.

14. The article of any one of claims 1-13, wherein the porous sintered glass and / or ceramic material comprises a sintering aid material.

15. The article of claim 14, wherein the porous sintered glass and / or ceramic material comprises the sintering aid material in an amount of at least 1 wt%.

16. The article of claim 14, wherein the porous sintered glass and / or ceramic material comprises the sintering aid material in an amount from 1 wt% to 25 wt%.

17. The article of any one of claims 14-16, wherein the sintering aid material comprises a borate, a phosphate, an alkali oxide, an alkali hydroxide, an alkali carbonate, an alkaline earth oxide, an alkaline earth hydroxide, an alkaline earth carbonate, an alkali silicate, an alkali alumino-silicate, an alkaline earth silicate, an alkaline earth alumino-silicate, a transition metal oxide, a transition metal hydroxide, a transition metal carbonate, or a combination thereof.

18. The article of any one of claims 14-17, wherein the sintering aid material comprises potassium.

19. The article of any one of claims 13-18, wherein the sintering aid material comprises hollow glass microspheres.

20. The article of any one of claims 1-19, wherein the porous sintered glass and / or ceramic material of the article has a coefficient of thermal expansion (RT-500°C) of at most 30 xlO"7oC’1.

21. The article of any one of claims 1-20, wherein the porous sintered glass and / or ceramic material of the article has a coefficient of thermal expansion (RT-500°C) of at most 20 xlO"7oC1.

22. The article of any one of claims 1-21, wherein the porous sintered glass and / or ceramic material has a modulus of rupture, MOR, and the intersecting array of walls define a closed frontal area, CFA, the article, and wherein a normalized strength of the article is at least 500 psi, where the normalized strength is determined by dividing the modulus of rupture by the closed frontal area when the closed frontal area is given as a percent of a total cross-sectional area of the article.

23. The article of claim 22, wherein the normalized strength is at least 1000 psi.

24. The article of any one of claims 1-23, wherein the porous sintered glass and / or ceramic material has a porosity of at least 50%.

25. The article of any one of claims 1-24, wherein the porous sintered glass and / or ceramic material has a median pore size of at most 1. 1 pm.

26. An amorphous silica article, comprising: a porous sintered glass and / or ceramic material comprised of at least 50 wt% diatomaceous earth and having: a porosity of at least 50%; and a median pore size of at most 1. 1 pm.

27. An amorphous silica article, comprising: a porous sintered glass and / or ceramic material comprised of at least 50 wt% diatomaceous earth and having: a bulk density of less than or equal to 1.2 g / cm3; and a median pore size of less than 1. 1 pm.

28. The amorphous silica article of either of claims 26 or 27, wherein the article has a honeycomb structure comprising an array of intersecting walls that define channels extending axially through the article, wherein the walls comprise the porous sintered glass and / or ceramic material.

29. A method of manufacturing a porous amorphous silica article, comprising: forming a green body from a batch mixture, the batch mixture comprising at least 50 wt% of a diatomaceous earth particle powder with respect to 100% inorganic raw materials in the batch mixture; firing the green body form the article by sintering the diatomaceous earth particles together into a porous, sintered glass and / or ceramic material, wherein a soak temperature during the firing is at most 1000°C.

30. The method of claim 29, wherein the article comprises a honeycomb body comprising an array of intersecting walls that define a plurality of channels extending axially through the article, and forming the green body comprises extruding the batch mixture through a honeycomb extrusion die.

31. The method of any one of claims 29-30, wherein the soak temperature between 700°C and 950°C.

32. The method of any one of claims 29-31, wherein the batch mixture comprises from 50 wt% to 95 wt% diatomaceous earth with respect to 100% inorganic raw materials in the batch mixture.

33. The method of any one of claims 29-32, wherein the batch mixture comprises at least 65 wt% diatomaceous earth with respect to 100% inorganic raw materials in the batch mixture.

34. The method of any one of claims 29-33, wherein the batch mixture comprises at least 80 wt% amorphous silica with respect to 100% inorganic raw materials in the batch mixture.

35. The method of any one of claims 29-34, wherein the batch mixture comprises at least 10 wt% fused silica in addition to the diatomaceous earth with respect to 100% inorganic raw materials in the batch mixture.

36. The method of any one of claims 29-35, wherein the batch mixture comprises at least 5 wt% of an inorganic oxide fdler.

37. The method of claim 36, wherein the inorganic oxide fdler comprises an aluminosilicate.

38. The method of claim 36, wherein the inorganic oxide fdler comprises kaolin clay.

39. The method of claim 36, wherein the batch mixture comprises from 5 wt% to 25 wt% of the inorganic oxide fdler with respect to 100% inorganic raw materials in the batch mixture.

40. The method of any one of claims 29-39, wherein the porous sintered glass and / or ceramic material comprises a sintering aid material.

41. The method of claim 40, wherein the porous sintered glass and / or ceramic material comprises the sintering aid material in an amount of at least 1 wt% with respect to 100% inorganic raw materials in the batch mixture.

42. The method of claim 40, wherein the porous sintered glass and / or ceramic material comprises the sintering aid material in an amount from 1 wt%to 25 wt% with respect to 100% inorganic raw materials in the batch mixture.

43. The method of any one of claims 40-42, wherein the sintering aid material comprises a borate, a phosphate, an alkali oxide, an alkali hydroxide, an alkali carbonate, an alkaline earth oxide, an alkaline earth hydroxide, an alkaline earth carbonate, an alkali silicate, an alkali alumino-silicate, an alkaline earth silicate, an alkaline earth alumino-silicate, a transition metal oxide, a transition metal hydroxide, a transition metal carbonate, or a combination thereof.

44. The method of any one of claims 40-43, wherein the sintering aid material comprises potassium.

45. The method of claims 44, wherein the sintering aid material comprises a carbonate, oxide, hydroxide, or nitrate of potassium.

46. The method of any one of claims 40-45, wherein the sintering aid material comprises hollow glass microspheres.

47. The method of any one of claims 29-46, wherein the porous, sintered glass and / or ceramic material of the article has a coefficient of thermal expansion (RT-500°C) of at most 30 xl0-7oC-1.

48. The method of any one of claims 29-47, wherein the porous, sintered glass and / or ceramic material of the article has a coefficient of thermal expansion (RT-500°C) of at most 20 xl0’7oC’1.

49. The method of any one of claims 31-48, wherein the porous sintered glass and / or ceramic material of the article has a modulus of rupture, MOR, and the intersecting array of walls define a closed frontal area, CFA, the article, and wherein a normalized strength of the article is at least 500 psi, where the normalized strength is determined by dividing the modulus of rupture by the closed frontal area when the closed frontal area is given as a percent of a total cross-sectional area of the article.

50. The method of claim 49, wherein the normalized strength is at least 1000 psi.

51. The method of any one of claims 29-49, wherein the porous sintered glass and / or ceramic material has a porosity of at least 50%.

52. The method of any one of claims 29-51, wherein the porous sintered glass and / or ceramic material has a median pore size of at most 1.1 pm.

53. The method of any one of claims 29-52, wherein the batch mixture comprises at least 10 wt% pore former as a superaddition with respect to 100% inorganic raw materials in the batch.

54. The method of any one of claims 29-53, wherein the batch mixture comprises at least 20 wt% pore former as a superaddition with respect to 100% inorganic raw materials in the batch.

55. The method of any one of claims 29-54, wherein the batch mixture comprises no pore former.

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