Methods and systems for efficient chemical processing

Abstract

In accordance with the purpose(s) of the present disclosure, as embodied and broadly described herein, the disclosure, in one aspect, relates to methods, compositions, and systems for conducting efficient thermochemical reactions to produce a product, e.g., the production of ethylene and NH3 from CH4 / N2. The disclosed methods comprise a non-equilibrium, continuous synthesis method that uses microwave pulsed heating to drive a thermochemical process. The disclosed methods allow for switching between endothermic and exothermic reactions in one continuous process or within a single system. Also disclosed are compositions, i.e., catalysts, useful in the disclosed methods, and devices or systems for carrying out the disclosed methods.

Description

METHODS AND SYSTEMS FOR EFFICIENT CHEMICAL PROCESSINGCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This Application claims the benefit of U.S. Provisional Application No. 63 / 646,015, filed on May 13, 2024, which is incorporated herein by reference in its entirety.BACKGROUND

[0002] Growing global demand to produce chemicals in a sustainable manner underlines the need for developing energy-efficient, low carbon processes for synthesizing important chemicals such as ethylene which form the basic building blocks for polymer, fertilizer, and other chemical products. Conventional manufacture of the ethylene by naphtha steam cracking is extremely energy-intensive and relies heavily on fossil fuels, hence contributing much to greenhouse emissions. New reactor technologies using electricity could offer one avenue to overcome this challenge using abundant feedstocks such as natural gas with renewable electricity for low-carbon production.

[0003] Methane (CH4), the primary constituent of natural gas, is an attractive feedstock for ethylene synthesis due to its abundance and affordability. However, its high molecular stability, characterized by a strong C-H bond (434 KJ / mol), negligible electron affinity, and low polarizability, makes its activation challenging. The oxidative coupling of methane (OCM) is a promising route to produce ethylene (C2H4) directly from methane. This process essentially consists of the activation of methane over a catalyst into CHx intermediates, which then dimerize into ethylene with minimal formation of unwanted by-products like carbon dioxide (CO2) and coke. Conventional high-temperature OCM processes (>1073 K) usually suffer from serious problems such as low selectivity, high energy consumption, and severe coking, which have significantly limited their scalability and commercial viability. Recent developments in microwave-assisted catalysis have pointed to new directions for overcoming these limitations.

[0004] Ethylene is one of the valuable feedstocks obtained from the petrochemical industry and is used as a raw material in the production of polyethylene, polyester, polystyrene, polyvinyl chloride, and many other intermediate products. In recent times, the conventional method for ethylene synthesis is thermal steam cracking, where naphtha and natural gas components such as ethane and propane, are used as raw materials where thermal steam cracking requires higher temperatures (800-850 C) due to its endothermic nature. Significant reactant conversions could only be achieved at high temperatures due to the thermodynamic limitations of methane dehydrogenation. However, as the reaction temperature increases, theyield of ethylene decreases because of side reacth product. The process also needs frequent equipment maintenance due to large amount of coke being formed in the furnace tubes during the reaction. For these reasons, amongst others, steam cracking is an expensive process which requires high energy and costly equipment.

[0005] Despite advances in chemical processing research, there is still a scarcity of methods, devices and compositions that can supplant conventional industrial thermochemical processes are typically operated at near equilibrium conditions with continuous thermal heating. The need for chemical processing methods, e.g., in the production of ethylene and NH3 from CH4 / N2, that offer improvements in CO2 reduction, process energy efficiency, product yield and selectivity, and catalyst stability are critically needed. These needs and other needs are satisfied by the present disclosure.SUMMARY

[0006] In accordance with the purpose(s) of the present disclosure, as embodied and broadly described herein, the disclosure, in one aspect, relates to methods, compositions, and systems for conducting efficient thermochemical reactions to produce a product, e.g., the production of ethylene and NH3from CH4 / N2. In a further aspect, disclosed herein is a nonequilibrium, continuous synthesis method that uses microwave pulsed heating to drive a thermochemical process. The disclosed methods allow for switching between endothermic and exothermic reactions in one continuous process or within a single system.

[0007] Disclosed are methods comprising flowing a feedstock gas over a catalyst; a heating step, wherein the catalyst is irradiated using pulsed microwave radiation, producing at least one heat cycle product; a quenching step, wherein the pulsed microwave radiation is stopped and the catalyst is allowed to cool, producing at least one quench cycle product; and cycling the heating step and the quenching step until a target condition is met.

[0008] Also disclosed are systems comprising: a reaction chamber; a catalyst, located inside the reaction chamber; a feedstock gas source, in fluid communication with the reaction chamber; and a microwave generator, configured to irradiate the reaction chamber with microwave radiation.

[0009] Also disclosed are compositions prepared using the disclosed methods.

[0010] Also disclosed are compositions prepared using the disclosed systems.

[0011] Other systems, methods, features, and advantages of the present disclosure will be or become apparent to one with skill in the art upon examination of the following drawings anddetailed description. It is intended that all such a advantages be included within this description, be within the scope of the present disclosure, and be protected by the accompanying claims. In addition, all optional and preferred features and modifications of the described embodiments are usable in all aspects of the disclosure taught herein. Furthermore, the individual features of the dependent claims, as well as all optional and preferred features and modifications of the described embodiments are combinable and interchangeable with one another.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

[0013] FIG. 1 shows a representative depiction of a disclosed microwave pulsed reactor for coupled endothermic and exothermic reactions.

[0014] FIG. 2 shows, without wishing to be bound by a particular theory, a representative mechanism for space-charge and Debye dielectric loss for microwave energy interacting with a catalyst surface resulting in selective bond activation of molecules.

[0015] FIG. 3 shows a representative disclosed cyber-physical data flow for real-time reactor optimization.

[0016] FIG. 4 shows a representative a physics-informed reinforcement learning approach for microwave reactor optimization.

[0017] FIGs. 5A-5B show exemplary representations of carbon monoliths with a non- suscepting washcoat (FIG. 5A) and a suscepting washcoat (FIG. 5B).

[0018] FIG. 6 shows a representative depiction of a disclosed microwave pulsed reactor for coupled endothermic and exothermic reactions.

[0019] FIGs. 7A-7B show representative data using a disclosed method in which the reaction was carried out at either 550 °C (FIG. 7A) or 600 °C (FIG. 7B) comparing methane conversion results for continuous mode versus pulsed mode microwave irradiation.

[0020] FIGs. 8A-8B show representative data using a disclosed method in which the reaction was carried out at either 550 °C (FIG. 8A) or 600 °C (FIG. 8B) comparing for hydrocarbon selectivity in the product mixture for continuous mode versus pulsed mode microwave irradiation.

[0021] FIGs. 9A-9B show representative data usin was carried out at either 550 °C (FIG. 8A) or 600 °C (FIG. 8B) comparing coke formation results for continuous mode versus pulsed mode microwave irradiation.

[0022] FIG. 10 shows representative data for methane coupling to ethylene using a disclosed 5% MnO2 / CeC>2 with the reaction carried out at 650 °C and the total C2 selectivity.

[0023] FIG. 11 shows representative data for methane coupling to ethylene using a disclosed 5% MnO2 / CeC>2 with the reaction carried out at 650 °C and the detailed C2 selectivity.

[0024] FIG. 12 shows representative data for heating profiles of a catalyst (5%MnO / CeO2) under varying microwave input powers (as indicated in figure).

[0025] FIG. 13 shows representative data for heating profiles of a catalyst (5%MnO / CeO2) under varying temperature ramping rates (as indicated in figure).

[0026] FIG. 14 shows representative data for CH4conversion using a catalyst (5%MnO / CeO2) with heating of the catalyst at 650 °C as a function of time on stream (minutes).

[0027] FIG. 15 shows representative data for C2H4 selectivity using a catalyst (5%MnO / CeO2) with heating of the catalyst at 650 °C as a function of time on stream (minutes).

[0028] FIG. 16 shows representative data for CH4conversion using a catalyst (1%Cs- 4%MnO / CeO2) with heating of the catalyst at 650 °C as a function of time on stream (minutes).

[0029] FIG. 17 shows representative data for C2H4selectivity using a catalyst (1%Cs- 4%MnO / CeO2) with heating of the catalyst at 650 °C as a function of time on stream (minutes).

[0030] FIG. 18 shows representative data for CH4conversion using two disclosed catalysts (5%Mn / CeO2 and 5%Mo / CeC>2, as indicated in the figure) with heating of the catalyst at 650 °C as a function of time on stream (minutes).

[0031] FIG. 19 shows representative data for C2H4selectivity using two disclosed catalysts (5%Mn / CeO2 and 5%Mo / CeC>2, as indicated in the figure) with heating of the catalyst at 650 °C as a function of time on stream (minutes).

[0032] FIG. 20 shows representative data for NH3production using 2Cs-4Ru / CeC>2 under different feed conditions (as indicated in the figure).

[0033] FIG. 21 shows representative data for the effect of CH4on NH3production.

[0034] FIG. 22 shows representative data for the effect of CH4on NH3production.

[0035] Additional advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or can be learned by practice of theinvention. The advantages of the invention will I: elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.DETAILED DESCRIPTION

[0036] Many modifications and other embodiments disclosed herein will come to mind to one skilled in the art to which the disclosed compositions and methods pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the disclosures are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. The skilled artisan will recognize many variants and adaptations of the aspects described herein. These variants and adaptations are intended to be included in the teachings of this disclosure and to be encompassed by the claims herein.

[0037] Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

[0038] As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present disclosure.

[0039] Any recited method can be carried out in the order of events recited or in any other order that is logically possible. That is, unless otherwise expressly stated, it is in no way intended that any method or aspect set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not specifically state in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including matters of logic with respect to arrangement of steps or operational flow, plain meaning derived from grammatical organization or punctuation, or the number or type of aspects described in the specification.

[0040] All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and / or materials in connection with which the publications are cited. The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention. Further, thedates of publication provided herein can be differe can require independent confirmation.

[0041] While aspects of the present disclosure can be described and claimed in a particular statutory class, such as the system statutory class, this is for convenience only and one of skill in the art will understand that each aspect of the present disclosure can be described and claimed in any statutory class.

[0042] It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosed compositions and methods belong. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0043] Prior to describing the various aspects of the present disclosure, the following definitions are provided and should be used unless otherwise indicated. Additional terms may be defined elsewhere in the present disclosure.A. DEFINITIONS

[0044] As used herein, “comprising” is to be interpreted as specifying the presence of the stated features, integers, steps, or components as referred to, but does not preclude the presence or addition of one or more features, integers, steps, or components, or groups thereof. Moreover, each of the terms “by”, “comprising,” “comprises”, “comprised of,” “including,” “includes,” “included,” “involving,” “involves,” “involved,” and “such as” are used in their open, non-limiting sense and may be used interchangeably. Further, the term “comprising” is intended to include examples and aspects encompassed by the terms “consisting essentially of” and “consisting of.” Similarly, the term “consisting essentially of” is intended to include examples encompassed by the term “consisting of.

[0045] As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a product” or “a reactant” includes, but is not limited to, two or more such products, reactants, and the like.

[0046] It should be noted that ratios, concentrations, amounts, and other numerical data can be expressed herein in a range format. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of theother endpoint. It is also understood that there are that each value is also herein disclosed as “about” that particular value in addition to the value itself. For example, if the value “10” is disclosed, then “about 10” is also disclosed. Ranges can be expressed herein as from “about” one particular value, and / or to “about” another particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms a further aspect. For example, if the value “about 10” is disclosed, then “10” is also disclosed.

[0047] When a range is expressed, a further aspect includes from the one particular value and / or to the other particular value. For example, where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the disclosure, e.g. the phrase “x to y” includes the range from x’ to ‘y’ as well as the range greater than x’ and less than ‘y’. The range can also be expressed as an upper limit, e.g. ‘about x, y, z, or less’ and should be interpreted to include the specific ranges of ‘about x’, ‘about y’, and ‘about z’ as well as the ranges of ‘less than x’, less than y’, and ‘less than z’. Likewise, the phrase ‘about x, y, z, or greater’ should be interpreted to include the specific ranges of ‘about x’, ‘about y’, and ‘about z’ as well as the ranges of ‘greater than x’, greater than y’, and ‘greater than z’. In addition, the phrase “about x’ to ‘y’”, where x’ and ‘y’ are numerical values, includes “about x’ to about ‘y’”.

[0048] It is to be understood that such a range format is used for convenience and brevity, and thus, 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. To illustrate, a numerical range of “about 0.1% to 5%” should be interpreted to include not only the explicitly recited values of about 0.1% to about 5%, but also include individual values (e.g., about 1 %, about 2%, about 3%, and about 4%) and the sub-ranges (e.g., about 0.5% to about 1.1%; about 5% to about 2.4%; about 0.5% to about 3.2%, and about 0.5% to about 4.4%, and other possible sub-ranges) within the indicated range.

[0049] As used herein, the terms “about,” “approximate,” “at or about,” and “substantially” mean that the amount or value in question can be the exact value or a value that provides equivalent results or effects as recited in the claims or taught herein. That is, it is understood that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact but may be approximate and / or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art such that equivalent results or effects are obtained. In some circumstances, the value that provides equivalent results or effects cannot be reasonablydetermined. In such cases, it is generally understo about” mean the nominal value indicated ±10% variation unless otherwise indicated or inferred. In general, an amount, size, formulation, parameter or other quantity or characteristic is “about,” “approximate,” or “at or about” whether or not expressly stated to be such. It is understood that where “about,” “approximate,” or “at or about” is used before a quantitative value, the parameter also includes the specific quantitative value itself, unless specifically stated otherwise.

[0050] As used herein, the term “effective amount” refers to an amount that is sufficient to achieve the desired modification of a physical property of the composition or material. For example, an “effective amount” of a temperature refers to an amount that is sufficient to achieve the desired improvement in the property modulated by the formulation component, e.g. achieving the desired level of modulus. The specific level in terms of wt% in a composition required as an effective amount will depend upon a variety of factors including the amount and type of olefin that is desired, amount and type of fuel that is desired, and economic considerations.

[0051] As used herein, the terms “optional” or “optionally” means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

[0052] Unless otherwise specified, a percent of a component in a composition, reaction, mixture, product mix, and the like is a weight percent (%wt).

[0053] Unless otherwise specified, pressures referred to herein are based on atmospheric pressure (i.e. one atmosphere).B. INTRODUCTION

[0054] Despite advances in chemical processing research, there is still a scarcity of methods, devices and compositions that can supplant conventional industrial thermochemical processes are typically operated at near equilibrium conditions with continuous thermal heating. The need for chemical processing methods, e.g., in the production of ethylene and NH3 from CH4 / N2, that offer improvements in CO2 reduction, process energy efficiency, product yield and selectivity, and catalyst stability are critically needed. These needs and other needs are satisfied by the present disclosure.

[0055] Conventional industrial thermochemical processes are typically operated at near equilibrium conditions with continuous thermal heating. Improvements in energy efficiency of these processes, product yield and selectivity, and catalyst stability are needed. Additionally, there is a need for the decarbonization of thermal processes across industry, i.e., industrialthermochemical process that produce less CO2thar is a non-equilibrium, continuous synthesis method that uses microwave pulsed heating to drive a thermochemical process. This method allows for switching between endothermic and exothermic reactions in one continuous process or within a single system.

[0056] For example, constraints of conventional methods are seen in commercial steam cracker methods for ethylene production that require heat at 1000°C, CH4to C2H4 via syngas is multiple steps. Direct CH4upgrading to C2+ hydrocarbons is a long-standing technology goal, but coke formation dominates due to uncontrolled gas phase reactions. Conventional reactors cannot control selectivity as the heating is from outside in and is unselective, causing large temperature gradients that promote coke formation at hot spots. In a further example of the constraints of conventional technology, the cost of H2production and NH3decomposition (reverse reaction) under low pressure caused low yield of NH3. Ammonia synthesis based on Haber-Bosch process is operated at 400-500°C, 250-300 bar and it is difficult to scale down economically, limiting the application in smaller scale renewable power.

[0057] The present disclosure provides a programmable energy deposition technique via microwave pulsing and real-time optimization via machine learning that contributes to decarbonization of thermal processes across multiple industries. The disclosed methods can reduce thermal losses by precisely delivering electromagnetic energy directly into the catalysts. A non-equilibrium, and continuous synthesis technique is disclosed herein that uses microwave pulsed heating (by varying power and frequency over time) to rapidly switch between endothermic reactions and exothermic reactions. For example, as illustrated in FIG. 1 , under microwave power-on mode (heating), endothermic CH4coupling reaction takes place whereas under the microwave power-off mode (quenching), the exothermic NH3 synthesis is favored, while CH4coupling reaction is discouraged and coking is prevented:Equation 1 : 2CH4= C2H4+ 2H2(endothermic, 500-700 °C)Equation 2: 3H2+ N2= 2NH3(exothermic, 300-400 °C)

[0058] In addition to the advantages of achieving higher than equilibrium conversions for both reactions under lower temperatures than industrial processes (850-1000 °C for ethylene and 450-500 °C for NH3 synthesis), other advantages include heat integration where heat released from NH3 synthesis under power-off mode can preheat CH4 to facilitate CH4 coupling in the next power-on mode. The stoichiometric reaction based on CH4 and N2 are shown below:Equation 3: 3CH4+ N2= 1 ,5C2H4+ 2NH3

[0059] Hydrogen species (H or H*) produced from CH4dehydrogenation react with N2on the catalyst surface before it desorbs to form H2. Studies show that hydride (M-H) is more activethan H2, facilitating the NH3 synthesis in microwave and quenching provide a greater degree of control by matching timescales of the C2 intermediates without allowing a steady state to be reached that can lead to secondary products for coke formation.C. METHODS FOR CHEMICAL PROCESSING

[0060] In one aspect, the disclosure relates to methods for conducting efficient thermochemical reactions to produce a product, e.g., the production of ethylene and NH3from CH4 / N2. More specifically, in one aspect, the present disclosure relates to a non-equilibrium, continuous synthesis method that uses microwave pulsed heating to drive a thermochemical process. The disclosed methods allow for switching between endothermic and exothermic reactions in one continuous process or within a single system.

[0061] Referring again to FIG. 1 , the disclosed methods provide microwave-enabled coupling of exo- and endo-thermic reactions to achieve high energy efficiency and carbon neutral to carbon negative chemical manufacturing. Novel microwave reactor cavity design and integration with multifunctional, microwave susceptible catalysts are some of the important components of the process. The disclosed methods integrate advanced microwave reactor design with the modification of industrially relevant metal-supported zeolite (e.g. M-ZSM-5) and metal oxide (e.g. CrOx, CeO2) catalysts. Microwave energy can be delivered directly to the adsorbed, reacting species on the catalyst surface where it is converted to heat and influences localized electronic properties of the catalyst. The “co-benefit” of using microwave pulsed heating is the control of surface reactions to enhance the yield and selectivity beyond thermodynamic limitations.

[0062] In various aspects, the disclosed methods of applying pulsed microwave to heterogeneous materials provides selective and frequency-dependent heating mechanism. When such pulsed heating integrates, as disclosed herein, with optical sensos, it enables multi-reactions, including both exothermic and endothermic ones to take place in one reactor system. In a further aspect, the disclosed methods leverage online data acquired from the in- situ sensors, the real-time-optimization algorithm will systematically identify the optimal conditions for reactor operation.

[0063] Moreover, in a further aspect, the disclosed methods provide direct conversion of CH4to olefins without going through syngas formation or steam cracking. Selectivity and carbon yields are increased with concomitant elimination of certain downstream separation steps. The disclosed microwave pulsed selective heating provide energy utilization that can minimize the loss of energy compared to conventional thermal heating.

[0064] In a further aspect, the disclosed methoc microwave energy, thus the temperature of active sites (Tcat) can be heated to the desired reaction temperature whereas the bulk of the catalyst (Tmed) remains relatively cool. This temperature difference can significantly limit coke formation by avoiding unnecessary cracking reactions. Furthermore, the rapid switching between heating and cooling modes inhibits the intermediates that lead to coking the catalyst.

[0065] In a further aspect, the disclosed methods allow the equilibrium yield of ethylene to be increased as hydrogen is consumed via the NH3synthesis (N2+ 3H2= 2NH3). The presence of hydride will increase NH3formation rate higher than equilibrium.

[0066] In various aspects, the disclosed methods comprise flowing a feedstock gas over a catalyst; a heating step, wherein the catalyst is irradiated using pulsed microwave radiation, producing at least one heat cycle product; a quenching step, wherein the pulsed microwave radiation is stopped and the catalyst is allowed to cool, producing at least one quench cycle product; and cycling the heating step and the quenching step until a target condition is met.

[0067] Examples of reactions that can be driven by this method include the CH4coupling reaction to produce C2H4and H2(endothermic process) and NH3synthesis from H2and N2(exothermic process). For these and other thermochemical processes, higher than equilibrium conversions can be achieved for both the endothermic and exothermic reactions under lower temperatures than typical industrial processes (e.g., 850-1000°C for C2H4and 450-500°C for NH3synthesis)> Other advantages include heat integration where heat released from the exothermic process can preheat the catalyst to facilitate the endothermic reaction process. Switching between endothermic and exothermic processes can also reduce coking.

[0068] The feedstock gas can include compounds that are reactants in the endothermic and exothermic processes, such as a gas comprising CH4, N2, or a combination thereof. The feedstock gas can include shale gas or biogases.

[0069] The method can be conducted at ambient pressure or higher pressures. In one aspect, the pressure can be varied during the process.

[0070] Microwave heating is associated with three types of mechanisms: conduction loss heating, dielectric heating, and magnetic heating. The thermal energy (P) originating from microwave radiation can be estimated from Equation (4), where the first, second and third terms in the equation expresses these three types of heating on sequence.Equation 4: P = 0. 5o-|£|2+ TT / '£0£" |£'|2+ nf .0^ \H\2In Equation (4), |E| and |H| denote the strength of th respectively; o is the electrical conductivity; f is the frequency of the microwaves; s0is the permittivity in vacuum; E" is the relative dielectric loss factor; / z0is the magnetic permeability in vacuum; and p" is the relative magnetic loss factor. The penetration depth (DP) of microwaves is an important factor that determine the effect of microwave heating in microwave-assisted heterogeneous catalysis. DPis defined as the depth where the microwave power drops to e-1(about 37%) of the initial value. It can be estimated from Equation (5): Equationwhere a) is the angular frequency, E' represents the dielectric constant, p' is the amount of magnetic energy stored within the material, and se''ffis related to conductivity and dielectric loss factor via the relation of E"ff= E" + — .

[0071] The foregoing shows, without wishing to be bound by a particular theory, that the microwave heating of materials depends on the electrical, dielectric and magnetic properties of the materials as well as the frequency and temperature, because the dielectric constant and the dielectric loss, both dependent from the temperature, are present in the equation.

[0072] Microwave irradiation provides a means for highly focused, site-specific heating of a catalyst, substrate (such as a solid catalyst support), or reactor contents, for chemical and / or materials synthesis and processing. This approach offers tighter control of temperature profiles on / near reactive surfaces, reducing temperature gradients in the reactor, lowering bulk temperatures of process streams, and reducing transients during startup and shutdown. FIG. 2 illustrates how an applied microwave field can interact with a metal oxide catalyst by relaxation processes, which involves the coupling of the radiation with dipoles in the solid catalyst. These dipoles can be defect sites (i.e. atomic vacancies) in the catalysts or unsaturated bonds on the surface of catalysts. Experimental results demonstrated how the material can be tuned for improved activity in the microwave by modifying functional groups on the catalyst surface (Refs. 3-5).

[0073] Microwaves interact with materials at a molecular level which provides an avenue for non-isothermal conditions within the catalyst structure. Microwaves can be operated under a number of ways, constant power and pulse power modes to maintain a reaction temperature. In a constant power mode, the material can reach a bulk isothermal state with the potential of active metal sites only reaching a temperature delta of ~50 °C. In contrast, under a pulsed power mode, the material has an opportunity to relax providing an avenue for a largertemperature delta (e.g. >300 °C) between the met microwave absorbing materials and non-absorbing materials. In addition to the thermal delta, the microwave pulses can supply field intensification points between dielectric materials or conductive sites. The evaluation of the effect of frequency will therefore provide the ability to study the increase in volumetric energy of the applied field as it related to rise in temperature. The increase in frequency will also result in larger local field intensifications. In this project, E- field and / or H-filed heating will be conducted in pulsed microwave heating. This microwavebased process intensification technology supports a variety of industrial applications.

[0074] In various aspects, in-situ temperatures measurement can be conducted using optical fiber sensors (OFS) at the (several) pm scale. OFS have well-known advantages for in situ and spatial resolved measurements, which are challenging at high temperatures due to strong EM interference caused by microwave excitation and chemical reactivity. These advantages include high sensitivity, relatively small size (several pm), high temperature capability (up to 800 and 1000 °C for long and short operation, respectively), immunity to EM interference, multiplexing capability for distributed measurement, and chemical inertness. An exemplary miniaturized OFS can comprise a Michelson interferometer (Ml), e.g., see Refs. 6-7, a Fabry- Perot interferometer (FPI), a fiber Bragg grating (FBG), and a long period fiber grating (LPFG). These sensors can all operate in a high temperature environment, but they are uniquely designed for different applications. The Ml sensor is suitable for temperature measurement, whereas a FPI sensor can be fabricated for temperature and pressure measurements.

[0075] Real-time optimization (RTO) based on first principle and / or machine learning (ML) models can effectively enhance process efficiency and safety under varying operating conditions (e.g., disturbances, changes in demand), as demonstrated in the team’s prior work, e.g., see Refs. 8-9. In this project, an ML-aided RTO algorithm and a cyber-physical prototype platform will be developed for the proposed microwave reactor (FIG. 3). Leveraging the online data acquired from the in-situ sensors, the RTO algorithm will systematically identify the optimal conditions for reactor operation (e.g., temperature peak, heating dynamics) while simultaneously addressing system uncertainties such as catalyst deactivation. This will contribute to reduce trial-and-error experimental efforts. The reactor simulation models developed from this project will also be integrated with ML models which can provide physicsbased process knowledge to ensure operational optimality and guide lab to commercial scale- up implementation.

[0076] In various aspects, disclosed methods provide an avenue to decarbonizing the olefin and NH3industries by introducing electrification into the process rather than simply using different combustion fired heaters. The introduction of microwave to the process results in “co-benefits” of improved energy efficiency and produ microwave-based catalytic reactor system can enable a process intensification platform technology that can be applied across many industrial sectors and is well-suited for modular process development and electrification of chemical and materials production. Microwave- enhanced chemical processes are also well-suited to take advantage of decentralized / stranded raw materials, including shale gas and biogas as well as similarly dispersed low-cost renewable electricity (e.g., solar PV and wind resources). In some aspects, the disclosed methods allow for a 100 % reduction in carbon intensity compared to a commercial CH4to ethylene process and 85% reduction in energy consumption.

[0077] The disclosed methods provided minimized coke formation due to the microwave noncontact heat generation. Determining the optimum microwave pulsing duration and power can be examined experimentally for optimal yield of olefins and NH3. The disclosed devices have the capability to assess the microwave heating in E-field (electric field is maximum at the center of the bed) and H-field (magnetic field distribution is at a maximum in the cavity center) configurations. This provides the opportunity to leverage heating due to the cavity designs as well as material properties (e.g., magnetic vs. dielectric) to better understand these heating modes and their resulting effects on bed temperature profiles. As such, the disclosed monolithic catalysts can be assessed for pulsed heating in both configurations and the testing will include assessing the strategic placement of the catalyst on the surface of the monolith (i.e., staged, mixed together, staggered) to improve synergy between materials. Catalysts can be screened and down selected for the performance of coupling reaction. The disclosed methods can be evaluated for power consumption per mass, mass converted per unit of time, composition of products.

[0078] One of the main deactivation pathways for dehydrogenation reaction is coke formation. As mentioned above, coke formation is already minimized in the disclosed methods using the microwave noncontact heat generation since cold spot formation is greatly reduced. Catalyst stability can be further improved as coke can be removed via the reverse Boudouard reaction (CO2 + C — > 2CO) during regeneration. The equilibrium yield of ethylene can also be increased as hydrogen is consumed. Disclosed monolithic catalysts can be utilized for longevity testing. After long duration of coupling testing, catalysts can be removed and examined. Catalysts can be characterized and evaluated for degree of deactivation, if any, and a mechanism(s) for deactivation will be proposed. Based on post catalyst characterization, catalysts can undergo a regeneration protocol (e.g., under a reducing atmosphere) that designed to minimize loss of activity for the catalysts and then the longevity test will be repeated.

[0079] In various aspects, the disclosed method; algorithm which can analyze the online sensing data and provide parameters to be tested for a optimal dynamic non-equilibrium microwave heating profile. This entails the optimal timevarying selection of temperature peak and heating / quenching timing with explicit considerations of catalyst deactivation across successive cycles.

[0080] For example, a reinforcement learning (RL) strategy can be developed to predict the time-dependent production of NH3and C2H4 based on sensing data. Operating variables will include microwave heating profile, reactor feed component ratio, time on stream, etc. The RL algorithm will be coupled with Gaussian process-based Bayesian optimization to enable automatic model tuning and target performance optimization against cumulative productivity, energy consumption, etc. The resulting Bayesian RL algorithm and the predicted optimal operating profile will be examined via online experimental implementation. This strategy can be readily generalized to a wide range of non-equilibrium chemical production processes employing unconventional microwave heating as well as conventional thermal heating.

[0081] Referring to FIG. 4, physics informed parameters (e.g., mass and energy balances) can be further incorporated into a Bayesian RL algorithm based on lab-scale reactor simulation models. The resulting physics-informed RL approach will be explicitly aware of process constraints (e.g., conversion laws) and temporal dynamics (e.g., time-dependent kinetics) to ensure the predictive optimization accuracy of this complex reactor system. Moreover, the integration of online experimental data with first-principles formulation will complement the simplifying modeling assumptions used in lab and commercial scale reactor modeling and simulation. The efficacy of the physics-informed Bayesian RL model can be benchmarked by the data-driven RL algorithm for reactor real-time optimization.

[0082] While ethylene and NH3are primary target products of the disclosed methods, the disclosed methods can also be applied to other thermochemical reactions beyond manufacturing of these products.D. CATALYSTS FOR THE DISCLOSED METHODS

[0083] The disclosed methods utilized pulsed microwave irradiation utilize the catalysts as disclosed herein. In various aspects, the catalyst can include a support comprised of at least a first material and a second material. In one aspect, the first material is configured to absorb microwave radiation. In another aspect, the first material is configured to not absorb microwave radiation. The first material comprises alumina, cerium oxide, magnesium, silica, iron oxide, carbon nanomaterials (such as carbon nanotube (CNT), carbon nanofiber (CNF), combinations thereof), zeolite, or any combination thereof. The second material can be amonolith structure, such as a monolith structure inc silica, iron oxide, carbon nanomaterials, zeolite, or any combination thereof. In one aspect, the second material can be considered an active zone of the catalyst, where only the second material can absorb microwave radiation.

[0084] The catalyst can further comprise metallic nanoparticles, such as Ru nanoparticles, Co nanoparticles, Mo nanoparticles, Fe nanoparticles, Ni nanoparticles, metal oxide nanoparticles thereof, or any combination thereof. In another aspect, the catalyst further includes active metals such as Ru, Mo, Fe, or any combination thereof. In another aspect, the catalyst can include metal promoters, such as Cs, K, Ni, or any combination thereof.

[0085] The disclosed method wherein the catalyst further comprises a first metal and a second metal; wherein the first metal is selected from and the second metal is a metal promoter, comprising Cs, K, or a combination thereof.

[0086] In a further aspect, the disclosed catalysts comprise a dehydrogenation catalyst and NH3synthesis catalyst on a carbon monolith. In a still further aspect, a carbon monolith comprises a comprise a dehydrogenation catalyst and NH3synthesis catalyst provided via a washcoat. In a yet further aspect, the washcoat can be a suscepting washcoat, a non- suscepting washcoat, or combinations thereof. In an even further aspect, the washcoat can be a suscepting washcoat. In an still further washcoat can be a non-suscepting washcoat. Exemplary representations of carbon monoliths with non-suscepting and suscepting washcoats are shown in FIGs. 5A-5B, respectively.

[0087] Catalyst layers can be applied to monolith forms with a washcoating or extrusion process as known to the skilled artisan. These methods provide a thin coating of the catalyst material on the inner honeycomb surfaces or mixed homogeneously throughout the monolith structure, respectively. Without wishing to be bound by a particular theory, it is believed that the carbon monolith can provide exceptional conductive heating to allow the desired catalysis to occur.

[0088] In various aspects, the catalyst can be a graphenic catalyst. Washcoats of mixtures of carbon and oxide can be synthesized, to combine the heat transfer and catalytic attributes of the respective components. In a further aspect, AlxSixOzthin, porous coatings on various carbon microwave heating cores have been demonstrated. The nanoparticles can be applied to the washcoat either before or after the washcoat is applied to the monolith. In the former case, the metal / oxide catalytic materials can be synthesized and then applied to the monolith in the washcoating process using strong electrostatic adsorption (SEA). This method can be used to produce stable homogeneous metal catalysts with controlled particle size on almostany support surface including graphitic and non-gr oxides, and likely high surface area silicon carbides.

[0089] Cross sections of the monoliths will be analyzed by SEM / EDXS to determine the uniformity of metal profiles. Metal nanoparticles on oxides and carbons applied prior to washcoat application will be characterized by XRD and STEM. In this case, SEM will be able to detect the nanoparticles if they are relatively large in size. If they are very well dispersed, however, the washcoat can be scraped from the monolith, ground, and subsequently analyzed by powder XRD (the instrument at USC has a high sensitivity solid state detector able to detect nanoparticles of even less than 1 nm) and STEM imaging with particle size analysis.E. SYSTEMS AND DEVICES FOR THE DISCLOSED METHODS

[0090] In various aspects, the disclosed devices can comprise subsystems for in-situ measurements to enable precise control of reaction operating conditions and pathways. A single crystal sapphire fiber-based temperature / Raman and the sensor can be embedded into the microwave cavity for in-situ measurement of temperature under pulsed microwave operation.

[0091] In a further aspect, the disclosed devices can comprise subsystems comprising embeddable optical fiber sensors for in-situ temperature measurements will be designed, fabricated, and tested. The requirements of the temperature measurements can be collected and analyzed to derive the specifications of the sensors and associated instrument.

[0092] In a further aspect, the disclosed devices comprise an subsystems to collect, process, and record data from the embedded sensors will be developed and tested, e.g., bench-top systems comprising optical components and subsystems. The disclosed devices can be controlled and logged by computers with internet, wireless, and / or bluetooth capabilities so that data can be stored and communicated digitally. The disclosed instruments can further comprise control software and programs to synchronize the microwave excitation and the in- situ temperature measurements so that the data can be used for microwave reactor temperature measurement and control under pulsing mode.

[0093] In a further aspect, the disclosed devices can further comprise embed in-situ sensors in the microwave reactors which can be manufactured using various laser-based methods and procedures, such as laser micromachining, 3D printing, laser sintering, and laser welding, will be investigated to embed miniaturized optical fiber sensors into the microwave reactors for in situ temperature measurements during operations.

[0094] In a further aspect, the disclosed devices can further comprise subsystems to provide microwave power-on and off times and power level and frequency that can be modulated toreduce secondary reaction that leads to coke form and selectivity, microwave reactor scale-up will be carried out with modeling tools.F. REFERENCES

[0095] References are cited herein throughout using the format of reference number(s) enclosed by parentheses corresponding to one or more of the following numbered references. For example, citation of references numbers 1 and 2 immediately herein below would be indicated in the disclosure as (Refs. 1 and 2).

[0096] Ref. 1 : Q. Wang, J. Pan, et al., Ternary ruthenium complex hydrides for ammonia synthesis via the associative mechanism, Nature Catalysis 4, no. 11 (2021 ): 959-967

[0097] Ref. 2: J. Hu, Method and Compositions for Direct, Simultaneous conversion of nitrogen and natural gas to value added compounds, U.S. patent application, PCT / US 19 / 58454 (Oct. 2019)

[0098] Ref. 3: X. Bai, B. Robinson, C. Killmer, Y. Wang, L. Li, J. Hu, Microwave catalytic reactor for upgrading stranded shale gas to aromatics, Fuel, 243 (2019), 485-492, 2019.

[0099] Ref. 4: Y. Deng, X. Bai, G. Veser, J. Hu, Microwave-assisted conversion of methane H-(Fe)-ZSM-5 : evidence for formation of hot metal sites, Chemical Engineering Journal, 420 (2021 ) 129670.

[0100] Ref. 5: Jianli Hu, Methods and compositions for microwave-assisted non-oxidative catalytic direct conversion of natural gas. U.S. Patent 10 (2021 ), 889, 763.

[0101] Ref. 6: L. Yuan, T. Wei, Q. Han, H. Z. Wang, J. Huang, L. Jiang, and H. Xiao, Fiber inline michelson interferometer fabricated by a femtosecond laser. Opt Lett 37(21 ) (2021 ), 4489-4491.

[0102] Ref. 7: T. Wei, H. Xiao, et. al., Fiber Inline Core-cladding-mode mach-zehnder interferometer fabricated by two-point CO2 laser irradiations, leee Photonic Tech L 21 (9-12) (2009), 669-671

[0103] Ref. 8: M. Ali, Y. Tian, et. al., Dynamic risk-based process design and operational optimization via multi-parametric programming. Digital Chemical Engineering, 7 (2023), 100096.

[0104] Ref. 9: E. N. Pistikopoulos, Y. Tian, R. Bindlish, Operability and control in process intensification and modular design: Challenges and opportunities. AIChE Journal, 67(5) (2021 ), e17204.

[0105] Ref. 10: B. Robinson, J. Hu, et. al., Catal added chemicals under microwave irradiation, Catalysis Today, 356 (2020), 3-10.

[0106] Ref. 11 : S. Tiwari, J. Hu, et. al., Activation of two highly stable molecules-N2 and CH4 to co-produce ammonia and ethylene, Chemical Engineering Journal, 413, 127501 , 2021 .

[0107] Ref. 12: Guo, X., Fang, G., Li, G., Ma, H., Fan, H., Yu, L., Ma, C., Wu, X., Deng, D., Wei, M. and Tan, D., 2014. Direct, nonoxidative conversion of methane to ethylene, aromatics, and hydrogen, science, 344(6184), pp.616-619.

[0108] Ref. 13: Keller, G.E. and Bhasin, M.M., 1982. Synthesis of ethylene via oxidative coupling of methane: I. Determination of active catalysts. Journal of Catalysis, 73(1 ), pp.9-19.

[0109] Ref. 14: Eryildirim, B., Arbag, H., Oktar, N. and Dogu, G., 2021. Comparison of microwave and conventionally heated reactor performances in catalytic dehydrogenation of ethane. International Journal of Hydrogen Energy, 46(7), pp.5296-5310.

[0110] Ref. 15: Marun, C., Conde, L.D. and Suib, S.L., 1999. Catalytic oligomerization of methane via microwave heating. The Journal of Physical Chemistry A, 103(22), pp.4332-4340.

[0111] Ref. 16: Jermolovicius, L.A., Pouzada, E.V.S., Do Nascimento, R.B., de Castro, E.R., Senise, J.T., Mente, B.B., Martins, M.C., Yamaguchi, S.M. and Sanchez, V.C., 2018. Greening the green ethylene with microwaves. Chemical Engineering and Processing-Process Intensification, 127, pp.238-248.

[0112] Ref. 17: Zhang, X., Lee, C.S.M., Mingos, D.M.P. and Hayward, D.O., 2003. Oxidative coupling of methane using microwave dielectric heating. Applied Catalysis A: General, 249(1 ), pp.151 -164.

[0113] Ref. 18: Roussy, G., Marchal, E., Thiebaut, J.M., Kiennemann, A. and Maire, G., 1997. C2+ selectivity enhancement in oxidative coupling of methane over microwave-irradiated catalysts. Fuel processing technology, 50(2-3), pp.261 -274.

[0114] Ref. 19: Wan, J., Tse, M., Husby, H. and Depew, M., 1990. High-power pulsed microwave catalytic processes: Decomposition of methane. Journal of microwave power and electromagnetic energy, 25(1 ), pp.32-38.

[0115] Ref. 20: Wildfire, C., Abdelsayed, V., Shekhawat, D. and Spencer, M.J., 2018. Ambient pressure synthesis of ammonia using a microwave reactor. Catalysis Communications, 115, pp.64-67.

[0116] Ref. 21 : Wang, Y., Khan, T.S., WildfireMicrowave-enhanced catalytic ammonia synthesis under moderate pressure and temperature. Catalysis Communications, 159, p.106344.

[0117] From the foregoing, it will be seen that aspects herein are well adapted to attain all the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the structure.

[0118] While specific elements and steps are discussed in connection to one another, it is understood that any element and / or steps provided herein is contemplated as being combinable with any other elements and / or steps regardless of explicit provision of the same while still being within the scope provided herein.

[0119] It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

[0120] Since many possible aspects may be made without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings and detailed description is to be interpreted as illustrative and not in a limiting sense.

[0121] It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to be limiting. The skilled artisan will recognize many variants and adaptations of the aspects described herein. These variants and adaptations are intended to be included in the teachings of this disclosure and to be encompassed by the claims herein.

[0122] Now having described the aspects of the present disclosure, in general, the following Examples describe some additional aspects of the present disclosure. While aspects of the present disclosure are described in connection with the following examples and the corresponding text and figures, there is no intent to limit aspects of the present disclosure to this description. On the contrary, the intent is to cover all alternatives, modifications, and equivalents included within the spirit and scope of the present disclosure.G. Examples

[0123] The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how the compounds, compositions, articles, devices and / or methods claimed herein are made and evaluated, and are intended to be purely exemplary of the disclosure and are not intended to limit the scope of what the inventors regard as their disclosure. Efforts have been made to ensure accuracy with respect tonumbers (e.g., amounts, temperature, etc.), but accounted for. Unless indicated otherwise, parts are parts by weight, temperature is in °C or is at ambient temperature, and pressure is at or near atmospheric.Example 1. Effect of microwave pulsing on methane conversion.

[0124] CH4 conversion into ethylene via disclosed microwave pulsing method was carried out as follows:• Catalyst: 5% Fe / H-ZSM-5• Fixed bed reactor, catalyst loading: 0.5g.• Flow rate / composition: CPU: 22.5 mL / min; N2: 7.5 mL / min• Reaction temperature: 550 °C or 600 °C• Pressure: 1 atm• Microwave Frequency: 2.45 GHz, Microwave Power: 0.45KW• Pulse mode condition: 3 sec per cycle, in each cycle, average time for power on was 50%• Continuous Mode: microwave power on all the time.

[0125] The catalyst was prepared as follows:• NH4-ZSM-5 zeolite catalyst with silica to alumina ratio (SAR) of 23 was purchased from Zeolyst Inc.• The zeolite catalyst was first calcined at 500°C in air for 3 hrs to convert the NH4-ZSM- 5 to H-ZSM-5.• Conventional incipient wetness technique was used to prepare the Fe / ZSM-5 Catalyst by adding certain amount of Fe(NO3)3-9H2O (99.95%, Sigma Aldrich) to reach desired Fe loading, i.e., 5 wt%. After drying the catalysts at 105 °C for 5 hrs, the powders were calcined in air at 550°C for 10 hrs.

[0126] The microwave system used is schematically shown in FIG. 6. Data obtained from the foregoing study are shown in FIGs. 7A-7B, 8A-8B, and 9A-9B in which data are shown for the study carried out at 550 °C or 600 °C showing results for continuous mode versus pulsed mode microwave irradiation with regard to methane conversion, hydrocarbon selectivity in the product mixture, and coke formation. These data show that:• the disclosed pulsed mode method leads to higher methane conversion at both 550 °C and 600 °C;• the disclosed pulsed mode method leads to the formation of desired products, e.g., ethylene, at both 550 °C and 600 °C; and• the disclosed pulsed mode method leads to lower coke formation at both 550 °C and 600 °C.Example 2. Effect of microwave pulsing on methane conversion.

[0127] CH4 conversion into ethylene via disclosed as follows:• Catalyst: MnO2 / CeO2 with 5% Mn loading• Flow rate / composition: 24 ml / min CF and 6 ml / min N2• Reaction temperature: 650 °C• Reaction time: 90 min

[0128] Data are shown in FIGs. W and 1 1. FIG. 10 shows methane coupling to ethylene using the 5% MnO2 / CeO2 at 650 °C with regard to total C2 selectivity. The data show:• The catalyst achieved an average 20% CH4conversion;• The results showed an average 85% total C2 selectivity; and• C2 products includes C2H4, C2H6and C2H2.It should be noted that acetylene can be selectively hydrogenated to ethylene, ethane can be dehydrogenated to ethylene. FIG. 1 1 shows methane coupling to ethylene using the 5% MnO2 / CeO2 at 650 °C with regard to detailed C2 selectivity. The data show that C2H4 selectivity is about 51.6%, C2H6 16.9%; and C2H2 16.6%.Example 3. Microwave-driven Non-oxidative Catalytic Conversion of Methane to Ethylene.

[0129] Chemicals: Pure Cerium (IV) Oxide (CeO2), Ru (III) nitrosyl nitrate (Ru[NO][NOs]3, Ru, manganese nitrate tetrahydrate (Mn (NO3)2.4H2O), cesium nitrate (CsNOs), ultra-pure gas mixture of H2, a feed gas mixture (CH4:N2= 4:1 ), hydrogen and argon were purchased from commercial chemical suppliers.

[0130] Catalyst Preparation: All catalysts were prepared using standard incipient wetness impregnation technique. During the preparation, nitrate salts were dissolved in distilled water and the resulting solution was impregnated onto the Cerium (IV) Oxide (CeO2). Later, the impregnated carrier was dried in steps for 30 min at 60 °C and for 2-3 hr. at 1 10°C. The mixture was then calcined at 550 °C for 3 hr.

[0131] Gas Analysis and Calculations: The product stream was analyzed using a four-channel Agilent 3000A micro gas chromatograph (GC) following the reactor. The micro-GC contained four columns, a molecular sieve, PLOT U, aluminum, and OV-1 , allowing for the analysis of hydrogen, nitrogen, methane, ethane, ethylene, propane, propylene, benzene, and toluene. The ethylene selectivity (Sethyiene), methane conversion (Cmethane), and the ethylene yield (Yethyiene) are defined as described in the following equations. Selectivity can be determined by, where N2is considered as the Internal Standard:Methane Reacted = Methane Input — Methane OutputMethane Output = Total flowrate x Methane Concentration from GC)Internal StandardTotal flowrate =Nitrogen Concentration (from GC)

[0132] Catalytic Reaction Process: The catalyst is loaded into the quartz tube and the height of the bed is maintained from 1.5-2 cm. The catalyst is pelletized and sieved before loading into the catalyst bed to avoid back pressure. Before starting the reaction, the catalyst bed is flushed with N2 as a carrier at a constant flow of 50 ml / min as it helps to carry the produced gas after the reaction to the Gas Chromatographer. The temperatures at which the reaction is being operated varies from 650 °C to 850 °C and the reaction was carried for about 2 hr. The feed composition was 24 ml / min CH4and 6 ml / min N2. The gaseous products include C2FU, C2H2, H2and CO.

[0133] Catalytic Performance of 5%MnO / CeO2: The reaction for ethylene synthesis was carried out at different temperatures of 650 °C, 750 °C and 850 °C at 0.3kW fixed microwave output power and 25 °C ramping rate to avoid overshooting of heating. Data are shown in FIG.12. The data show the heating profiles of a catalyst under varying microwave input powers: 0.3 Kw, 0.4 Kw, and 0.5 Kw. The data show that the catalyst stabilized at 0.3Kw input power within approximately 6.5 mins, whereas higher input powers required longer stabilization times. Based on this observation, 0.3 Kw microwave input power was selected for further studies.

[0134] Catalyst heating data under different temperature ramping intervals is shown in FIG.13. The data show the heating profiles of catalyst under varying temperature ramping rate: 15 °C, 25 °C, and 35 °C. The results demonstrated that the catalyst exhibited more stabilized behavior with 25 °C ramping rate when compared to other temperatures. No overshooting of temperature was observed with 25 °C ramping rate.

[0135] CH4conversion data using 5%MnO / CeO2 at different temperatures is shown in FIG.14. The data show that that CH4conversion increased over time, peaked and then showed a steady decline after approximately 45 minutes.

[0136] Selectivity data of C2H4 in the reaction usiiFIG. 15. The data show that the selectivity of ethylene changed as a function of time. Without wishing to be bound by a particular theory, it is believed that the change in selectivity is related to catalyst deactivation.

[0137] Catalytic Performance of 1%Cs-4%MnO / CeO2: Data relating to CH4conversion using 1 %Cs-4%MnO / CeC>2 at 650 °C are shown in FIG. 16. The data show a decrease in CH4conversion as a function of time. Selectivity data using the same catalyst are shown in FIG. 17, which show selectivity for ethylene increase as a function of time.

[0138] Catalytic Performance of 5%Mn / CeO2 versus 5%Mo / Ce02: Data comparing the catalytic performance of 5%Mn / CeO2 versus 5%Mo / Ce02 as it relates to CH4conversion is shown in FIG. 18. Data comparing the catalytic performance of 5%Mn / CeO2 versus 5%Mo / Ce02 as it relates to C2H4selectivity is shown in FIG. 19. From the foregoing, the 5%Mn / CeO2 may have some performance advantages as a catalyst for non-oxidative conversion of CH4to C2H4compared to 5%Mo / Ce02.Example 4. NH3production under different feed conditions using 2Cs-4Ru / CeO2 catalyst.

[0139] NH3production under different feed conditions using 2Cs-4Ru / CeO2 catalyst was assessed. The catalyst, 2Cs-4Ru / CeO2, was prepared by a wetness impregnation method. The reaction conditions for this study were as follows:• Catalyst loadings: 1 g of 2Cs-4Ru / CeO2 catalyst• Temperature: 360 °C (conventional heating)• Flow Rate: 50 SCCM• Pressures atmThe different feed conditions assessed were as follows:• H2:N2(3:1 )• H2:N2(1 :1)• H2:N2(1 :3)• H2:N2(3:1)+10% CH4

[0140] Data are shown in FIG. 20 for NH3 production under different feed conditions using 2Cs-4Ru / CeO2 catalyst. The data show that H2:N2(3:1 ) > H2:N2(1 :1 ) > H2:N2(1 :3) because higher H2availability enhanced both equilibrium conversion and reaction kinetics. Moreover, the data show that increased H2(3:1 ) shifts equilibrium towards NH3formation, while excess N2(1 :3) limited H2availability, reducing NH3yield.

[0141] Data are shown in FIG. 21 for the effect of CH4on NH3production. The data show thateffect of CH4 on NH3 production. Moreover, the data suggest, without wishing to be bound by a particular theory, that methane (CH4) could be adsorbed onto Ru active sites, competing with H2and N2for available surface sites.

[0142] NH3production under different feed conditions using 2Cs-4Ru / CeC>2 catalyst was assessed. The catalyst, 2Cs-4Ru / CeC>2, was prepared by a wetness impregnation method. The reaction conditions for this study were as described above. The feed compositions used in this study were as follows:• H2:N2 (3:1 )+10% CH4• H2:N2 (3:1 )+10% Ar

[0143] Data are shown in FIG. 22 pertaining to the effect of CH4on NH3production. The data show that adding CH4or Ar increased the total flow rate is increased to 50 ml / min while keeping the active reactants (H2and N2) at the same ratio (3:1 ); and that the NH3production rate decreased with the addition of CH4and Ar. Without wishing to be bound by a particular theory, the addition of CH4or Ar is a dilution effect since both showed similar production rates.

[0144] It should be emphasized that the above-described embodiments of the present disclosure are merely possible examples of implementations set forth for a clear understanding of the principles of the disclosure. Many variations and modifications may be made to the above-described embodiment(s) without departing substantially from the spirit and principles of the disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.

Claims

CLAIMSWhat is claimed is:

1. A method comprising: flowing a feedstock gas over a catalyst; a heating step, wherein the catalyst is irradiated using pulsed microwave radiation, producing at least one heat cycle product; a quenching step, wherein the pulsed microwave radiation is stopped and the catalyst is allowed to cool, producing at least one quench cycle product; and cycling the heating step and the quenching step until a target condition is met.

2. The method of claim 1 , wherein the catalyst comprises a support comprised of at least a first material and a second material.

3. The method of claim 2, wherein the first material comprises alumina, cerium oxide, magnesium, silica, iron oxide, carbon nanomaterials, zeolite, or any combination thereof.

4. The method of claim 2 or claim 3, wherein the second material comprises a monolith structure comprising alumina, cerium oxide, magnesium, silica, iron oxide, carbon nanomaterials, zeolite, or any combination thereof.

5. The method of any one of claims 2-4, wherein the first material is configured to absorb microwave radiation.

6. The method of any one of claims 1-5, wherein the catalyst further comprises metallic nanoparticles.

7. The method of claim 6, wherein the metallic nanoparticles comprise Ru nanoparticles, Co nanoparticles, Mo nanoparticles, Fe nanoparticles, Ni nanoparticles, metal oxide nanoparticles thereof, or any combination thereof.

8. The method of any one of claims 1-7, wherein the catalyst further comprises a first metal and a second metal; wherein the first metal is selected from Ru, Mo, Fe, or any combination thereof and the second metal is a metal promoter, selected from Cs, K, or a combinationthereof.

9. The method of any one of claims 1-8, wherein the microwave frequency is varied during the heating step.

10. The method of any one of claims 1-9, wherein the feedstock gas comprises CH4, C2H6, N2, or a combination thereof.1 1. The method of any one of claims 1-10, wherein the heat cycle product comprises C2H4.

12. The method of any one of claims 1-11 , wherein the quench cycle product comprises NH3.

13. The method of any one of claims 1-12, wherein the first material is configured to not absorb microwave radiation.

14. A composition prepared by a method of any one of claims 1 -13.

15. A system, comprising: a reaction chamber; a catalyst, located inside the reaction chamber; a feedstock gas source, in fluid communication with the reaction chamber; and a microwave generator, configured to irradiate the reaction chamber with microwave radiation.

16. A composition prepared using the system of claim 15.

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