A method for preparing synthesis gas by photothermal driven methane dry reforming

Abstract

The present invention provides a high entropy alloy loaded in CO 2 The present invention also discloses a corresponding efficient and sustainable method for preparing synthesis gas by photothermal driven dry reforming of methane. The specific supported high entropy alloy catalyst used has good photothermal conversion efficiency and can realize DRM technology to prepare synthesis gas under mild conditions. This process not only helps to alleviate the greenhouse effect but also improves energy utilization efficiency, greatly reducing production costs and energy consumption. The method provided by the present invention has an overall raw material conversion rate of more than 50%, and the yield of synthesis gas is 10 mol g ‑1 h ‑1 The overall selectivity is above 0.9, there are no hydrocarbon and alcohol products, the catalyst can operate stably for more than 100 hours, the reaction process is simple, the cycle is short, the catalyst is cheap and easy to obtain and can be reused, and the source of reactant raw materials is wide, and it has broad industrial application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparing synthesis gas by dry reforming of methane, and relates to the application of a supported high entropy alloy as a catalyst in preparing synthesis gas by dry reforming of a CO2 source and a light alkane source, and a method for preparing synthesis gas by dry reforming of a light alkane, and in particular to the application of a supported high entropy alloy as a catalyst in preparing synthesis gas by dry reforming of a CO2 source and a light alkane source, and a method for preparing synthesis gas by dry reforming of methane driven by light and heat. Background Art

[0002] Natural gas is not only a high-quality clean energy, but also an important chemical raw material. In the face of increasingly severe environmental problems, clean and environmentally friendly natural gas has attracted much attention compared to fossil energy such as coal and oil. The process of converting natural gas with CH4 as the main component into synthesis gas with a product selectivity close to 1 through methane dry reforming (DRM) technology not only helps to alleviate the greenhouse effect but also improves energy efficiency.

[0003] However, since the DRM reaction is highly endothermic, temperatures above 700°C are generally required to drive the reaction, resulting in huge energy consumption and environmental pollution. In addition, at such high temperatures, side reactions such as coking and reverse water gas reaction are thermodynamically inevitable, leading to catalyst deactivation and reduced selectivity.

[0004] Therefore, considering the cost of industrial production as well as energy crisis and environmental pollution, how to develop a new method of DRM technology that is greener, more environmentally friendly, has mild reaction conditions and high selectivity has become one of the focuses of attention of many forward-looking researchers in this field. Summary of the invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide an application of a loaded high entropy alloy as a catalyst in the preparation of synthesis gas by dry reforming of a CO2 source and a light alkane source, and a method for preparing synthesis gas by dry reforming of a light alkane, in particular, a method for preparing synthesis gas by photothermal driven dry reforming of methane. The present invention applies a loaded high entropy alloy to a DRM reaction, and obtains a method for preparing synthesis gas by photothermal driven dry reforming of methane, which can achieve efficient and highly selective preparation of synthesis gas under mild conditions, and the preparation method has simple steps and mild conditions, is suitable for large-scale production promotion and application, and has good practical prospects.

[0006] The present invention provides the use of a supported high entropy alloy as a catalyst in preparing synthesis gas by dry reforming a CO2 source and a light alkane source.

[0007] Preferably, the metals in the high entropy alloy include four or more of Co, Ni, Cu, Zn, Ru, Rh, Pd and Pt;

[0008] The supported carrier includes a metal oxide carrier and / or a titanate carrier;

[0009] The light alkanes include methane, ethane or propane.

[0010] Preferably, the molar ratio of the high entropy alloy to the carrier is (0.005-0.1):1;

[0011] The metal oxide carrier includes one or more of TiO2, CeO2, CaO, ZnO, Al2O3, MgO and SiO2;

[0012] The titanate carrier includes SrTiO3, Sr x Ba 1-x One or more of TiO3 (0<x<1), SrBaTiO3, CaTiO3 and SrZrO3;

[0013] The preparation conditions include preparing under energizing conditions.

[0014] Preferably, the preparation time is 0.1 to 300 hours;

[0015] The energy-enabling method includes illumination and / or heating;

[0016] The illumination intensity of the illumination is 10 to 5000 mW / cm 2 .

[0017] Preferably, the light source of the illumination includes one or more of natural light, xenon lamp, LED lamp, tungsten lamp and mercury lamp;

[0018] The temperature of the illumination is room temperature;

[0019] The heating temperature is 20-700°C.

[0020] Preferably, the CO2 source includes CO2 or a gas containing CO2;

[0021] The light alkane source includes light alkanes or gases containing light alkanes;

[0022] The CO2 source and the light alkane source include a mixed gas of CO2 and light alkanes or a mixed gas containing CO2 and light alkanes;

[0023] The molar ratio of the metal elements in the high entropy alloy is 1:1.

[0024] The present invention provides a method for preparing synthesis gas by dry reforming of light alkanes, comprising the following steps:

[0025] Under energized conditions, CO2 source and light alkane source are subjected to methane dry reforming reaction under the action of a supported catalyst loaded with a high entropy alloy to obtain CO and H2.

[0026] Preferably, the metals in the high entropy alloy include four or more of Co, Ni, Cu, Zn, Ru, Rh, Pd and Pt;

[0027] The molar ratio of the high entropy alloy to the loaded carrier is (0.005-0.1):1;

[0028] The support includes a metal oxide support and / or a titanate support.

[0029] Preferably, the pressure of the CO2 source is 0.1 to 10 MPa;

[0030] The pressure of the light alkane source is 0.1-10 MPa;

[0031] The energizing method includes illumination and / or heating.

[0032] Preferably, the illumination intensity of the illumination is 10 to 5000 mW / cm 2 ;

[0033] The heating temperature is 20-700°C;

[0034] The preparation time is 0.1 to 300 hours;

[0035] The reactor for performing the methane dry reforming reaction includes one or more of a quartz reactor, a glass reactor, a fixed bed reactor and a mobile phase reactor.

[0036] The present invention provides the use of a supported high entropy alloy as a catalyst in the preparation of synthesis gas by dry reforming of a CO2 source and a light alkane source. Compared with the prior art, the present invention is based on the development trend of international thermal catalytic DRM technology, photocatalytic CH4 conversion and CO2 reduction and believes that taking the photothermal driven DRM reaction as the research object, developing the design theory and preparation method of an ideal photothermal catalyst, and establishing a reasonable and reliable photothermal driven DRM reaction are the technical directions of related research.

[0037] Based on this, the present invention creatively applies the loaded high entropy alloy as a catalyst in the process of preparing synthesis gas by dry reforming of CO2 source and light alkane source. The present invention also discloses a corresponding efficient and sustainable method for preparing synthesis gas (CO and H2) by photothermal driven dry reforming (DRM) of methane. The present invention uses a high entropy alloy loaded on a metal oxide carrier or a titanate carrier as a catalyst. In a flow reactor, under external energy (such as focused sunlight irradiation), two greenhouse gases (CH4 and CO2 gases) are converted into an equal volume of synthesis gas under mild conditions. The product synthesis gas can be directly used for Fischer-Tropsch synthesis to manufacture high-value chemicals.

[0038] The specific supported high entropy alloy catalyst used in the present invention has a good photothermal conversion efficiency, and can realize the DRM technology to prepare synthesis gas under mild conditions. This process not only helps to alleviate the greenhouse effect but also improves the efficiency of energy utilization, greatly reducing production costs and energy consumption. In addition, the method of the present invention has the advantages of simple reaction process, short cycle, cheap and easy to obtain catalysts and reusable, wide sources of reactant raw materials, especially can directly use combustible ice, shale gas and natural gas as raw gas, etc., providing a new synthesis route for DRM to prepare synthesis gas, and has broad industrial application prospects.

[0039] The high entropy alloy catalyst used in the present invention has a good photothermal conversion efficiency, can drive the DRM technology to prepare synthesis gas under mild conditions, and is efficient, highly selective, and highly stable in producing synthesis gas, without hydrocarbon and alcohol products, and can be directly used for Fischer-Tropsch synthesis to produce high-value hydrocarbons and oil chemicals; the catalyst has high stability and can be stably operated for more than 100 hours without catalyst sintering and carbon deposition; in addition, the catalyst can also drive ethane dry reforming and propane dry reforming to prepare synthesis gas. This process not only helps to alleviate the greenhouse effect but also improves energy utilization efficiency, greatly reducing production costs and energy consumption. In addition, the method provided by the present invention has the advantages of simple reaction process, short cycle, cheap and easy to obtain catalyst and reusable, wide sources of reactant raw materials, especially can directly use combustible ice, shale gas and natural gas as raw gas, etc., providing a new synthesis route for DRM reaction to prepare synthesis gas, and has broad industrial application prospects.

[0040] The experimental results show that the method for preparing synthesis gas by dry reforming provided by the present invention can convert two equal volumes of greenhouse gases (CH4 and CO2 gases) into equal volumes of synthesis gas at room temperature by only using focused sunlight in a mobile phase reactor. The conversion rates of CH4 and CO2 are generally above 50%, and the yield of synthesis gas is above 10 mol g -1 h -1 The overall selectivity is above 0.9, there are no hydrocarbon and alcohol products, and the catalyst can operate stably for more than 100 hours. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The synthesis gas yield rate and selectivity obtained in the dry reforming of methane provided in Example 1 of the present invention;

[0042] Figure 2 The results are the reusability performance results of the SrTiO3-loaded high entropy alloy catalyst provided by the present invention. DETAILED DESCRIPTION

[0043] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the invention.

[0044] All raw materials of the present invention have no particular limitation on their sources, and can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0045] The raw materials used in the present invention have no particular limitation on their purity. In the present invention, the raw materials are preferably analytically pure or of conventional purity in the application field of dry reforming of methane (DRM).

[0046] The brands and abbreviations of all raw materials of the present invention are conventional brands and abbreviations in the art. Each brand and abbreviation is clear and definite in the field of its related use. Those skilled in the art can purchase them from the market or prepare them by conventional methods according to the brands, abbreviations and corresponding uses.

[0047] The abbreviations of all processes of the present invention are conventional abbreviations in the field, and each abbreviation is clear and unambiguous in the field of its related use. Those skilled in the art can understand its conventional process steps based on the abbreviations.

[0048] The present invention provides the use of a supported high entropy alloy as a catalyst in preparing synthesis gas by dry reforming a CO2 source and a light alkane source.

[0049] In the present invention, the metals in the high entropy alloy preferably include four or more of Co, Ni, Cu, Zn, Ru, Rh, Pd and Pt, and more preferably four, five or six of Co, Ni, Cu, Zn, Ru, Rh, Pd and Pt.

[0050] In the present invention, the supported carrier preferably includes a metal oxide carrier and / or a titanate carrier, and more preferably a metal oxide carrier or a titanate carrier.

[0051] In the present invention, the light alkane preferably includes methane, ethane or propane, and may be methane in particular.

[0052] In the present invention, the molar ratio of the high entropy alloy to the carrier is preferably (0.005-0.1):1, more preferably (0.05-0.09):1, and more preferably (0.06-0.08):1.

[0053] In the present invention, the metal oxide carrier includes one or more of TiO2, CeO2, CaO, ZnO, Al2O3, MgO and SiO2, more preferably TiO2, CeO2, CaO, ZnO, Al2O3, MgO or SiO2.

[0054] In the present invention, the titanate carrier preferably includes SrTiO3, Sr x Ba 1-x TiO3 (0<x<1), SrBaTiO3, CaTiO3 and SrZrO3, more preferably SrTiO3, Sr x Ba 1-x TiO3 (0<x<1), SrBaTiO3, CaTiO3 or SrZrO3.

[0055] In the present invention, the preparation conditions preferably include preparing under energizing conditions.

[0056] In the present invention, the preparation time is preferably 0.1 to 300 hours, more preferably 1 to 200 hours, and more preferably 10 to 100 hours.

[0057] In the present invention, the energy-empowering method preferably includes illumination and / or heating, more preferably illumination or heating, and specifically, focused sunlight irradiation.

[0058] In the present invention, the illumination intensity of the illumination is preferably 10 to 5000 mW / cm 2 , more preferably 100 to 4000 mW / cm 2 , more preferably 1000 to 3000 mW / cm 2 .

[0059] In the present invention, the light source of the illumination preferably includes one or more of natural light, xenon lamp, LED lamp, tungsten lamp and mercury lamp, more preferably natural light, xenon lamp, LED lamp, tungsten lamp or mercury lamp.

[0060] In the present invention, the temperature of the light irradiation is preferably room temperature.

[0061] In the present invention, the heating temperature is preferably 20 to 700°C, more preferably 100 to 500°C, and even more preferably 200 to 300°C.

[0062] In the present invention, the CO 2 source preferably includes CO 2 or a gas containing CO 2 .

[0063] In the present invention, the light alkane source preferably includes a light alkane source or a gas containing a light alkane source.

[0064] In the present invention, the CO2 source and the light alkane source preferably include a mixed gas of CO2 and a light alkane source or a mixed gas containing CO2 and a light alkane source.

[0065] In the present invention, the molar ratio of the metal elements in the high entropy alloy is preferably 1:1.

[0066] The present invention provides a method for preparing synthesis gas by dry reforming of light alkanes, comprising the following steps:

[0067] Under energized conditions, CO2 source and light alkane source are subjected to methane dry reforming reaction under the action of a supported catalyst loaded with a high entropy alloy to obtain CO and H2.

[0068] In the present invention, the high entropy alloy is preferably a high entropy alloy having the ability to dissociate CH bonds and C=O bonds and the ability to convert light into heat, and the metals in the high entropy alloy preferably include four or more of Co, Ni, Cu, Zn, Ru, Rh, Pd and Pt, and more preferably four of Co, Ni, Cu, Zn, Ru, Rh, Pd and Pt.

[0069] In the present invention, the molar ratio of the high entropy alloy to the supported carrier is preferably (0.005-0.1):1, more preferably (0.05-0.09):1, and more preferably (0.06-0.08):1.

[0070] In the present invention, the carrier preferably includes a metal oxide carrier and / or a titanate carrier, and more preferably a metal oxide carrier or a titanate carrier.

[0071] In the present invention, the light alkane preferably includes one or more of methane, ethane and propane, more preferably methane, ethane or propane, and specifically methane.

[0072] In the present invention, the pressure of the CO2 source is preferably 0.1 to 10 MPa, more preferably 1 to 8 MPa, and more preferably 3 to 6 MPa.

[0073] In the present invention, the pressure of the light alkane source is preferably 0.1 to 10 MPa, more preferably 1 to 8 MPa, and even more preferably 3 to 6 MPa.

[0074] In the present invention, the energizing method preferably includes illumination and / or heating, more preferably illumination or heating.

[0075] In the present invention, the illumination intensity of the illumination is 10 to 5000 mW / cm 2 , more preferably 100 to 4000 mW / cm 2 , more preferably 1000 to 3000 mW / cm 2 .

[0076] In the present invention, the heating temperature is preferably 20 to 700°C, more preferably 100 to 500°C, and even more preferably 200 to 300°C.

[0077] In the present invention, the preparation time is preferably 0.1 to 300 hours, more preferably 1 to 200 hours, and more preferably 10 to 100 hours.

[0078] In the present invention, the reactor for performing the light alkane dry reforming reaction preferably includes one or more of a quartz reactor, a glass reactor, a fixed bed reactor and a mobile phase reactor, and more preferably a quartz reactor, a glass reactor, a fixed bed reactor or a mobile phase reactor.

[0079] The present invention is to complete and refine the overall preparation process, better ensure the progress of the light alkane dry reforming reaction and the product composition, and further improve the efficiency, high selectivity and high stability of the light alkane dry reforming reaction. The above-mentioned method for preparing synthesis gas by light-thermal driven light alkane dry reforming preferably includes the following steps:

[0080] A new method for preparing synthesis gas by photothermal driven dry reforming of methane (DRM) uses a high entropy alloy supported by strontium titanate (SrTiO3) as a catalyst to convert two greenhouse gases (CH4 and CO2 gases) into equal volumes of synthesis gas (CO and H2) under mild conditions in a flow reactor under the irradiation of focused sunlight.

[0081] Specifically, the raw gas used may be in the form of pure CH4 and CO2 gas, or in the form of a gas containing CH4 and CO2. The term "gas containing CH4 and CO2" refers to a gas mixture containing CH4 and CO2. In addition, the raw gas may also be directly derived from methane hydrate, shale gas and natural gas.

[0082] Specifically, the catalyst carrier SrTiO3 can be directly purchased as cheap commercial SrTiO3, or SrTiO3 with a specific structure can be synthesized according to experimental needs.

[0083] Specifically, the catalyst carrier includes but is not limited to SrTiO3, and other commercial oxides may also be used instead of SrTiO3, such as titanate materials (Sr x Ba 1-xTiO3, SrBaTiO3, CaTiO3 and SrZrO3, etc.) and oxide materials (TiO2, CeO2, ZnO, Al2O3, MgO, SiO2, etc.).

[0084] Specifically, the components of the high entropy alloy include but are not limited to Co, Ni, Cu, Zn, Ru, Rh, Pd, Pt, etc.

[0085] Specifically, the molar ratio of the high entropy alloy and SrTiO3 loaded in the catalyst is 0.005 to 0.1:1.

[0086] Specifically, the illumination intensity of the illumination condition is 10-5000 mW / cm 2 .

[0087] Specifically, the light source used for the lighting condition is one or more selected from natural light, xenon lamp, LED lamp, tungsten lamp and mercury lamp.

[0088] Specifically, the reaction temperature is 20-600°C and the reaction running time is 0-200h.

[0089] Specifically, the reactor is a quartz reactor, a glass reactor, a fixed bed reactor or a mobile phase reactor.

[0090] Specifically, the CH4 gas and CO2 gas and the pressure in the reactor are 0.1MPa to 10MPa.

[0091] Furthermore,

[0092] The present invention provides a method for preparing synthesis gas by using a photothermal driven DRM technology, using a high entropy alloy loaded with SrTiO3 as a catalyst, and converting two equal volumes of greenhouse gases (CH4 and CO2 gases) into equal volumes of synthesis gas at room temperature in a flow reactor under the irradiation of focused sunlight.

[0093] In a preferred embodiment, the raw gas used may be derived from the form of pure CH4 and CO2 gas, or may be in the form of a gas containing CH4 and CO2. The term "gas containing CH4 and CO2" refers to a gas mixture containing CH4 and CO2. In addition, the raw gas may also be directly derived from combustible ice, shale gas and natural gas. Preferably, the gas containing CH4 and CO2 gas has a volume content greater than 10%.

[0094] In a preferred embodiment, the flow rates of the raw gas CH4 and CO2 are 5-60 mL / min, respectively. Preferably, the flow rates of CH4 and CO2 are 10 mL / min, respectively. -1 .

[0095] In a preferred embodiment, the catalyst carrier SrTiO3 can be directly purchased as cheap commercial SrTiO3, or SrTiO3 with a specific structure can be synthesized according to experimental needs.

[0096] In a preferred embodiment, the catalyst carrier is not limited to SrTiO3, and other commercial oxides may also be used instead of SrTiO3, such as titanate materials (Sr x Ba 1-x TiO3, SrBaTiO3, CaTiO3 and SrZrO3, etc.) and oxide materials (TiO2, CeO2, ZnO, Al2O3, MgO, SiO2, etc.). Commercial SrTiO3 is preferred as the carrier.

[0097] The components of the high entropy alloy include but are not limited to Co, Ni, Cu, Zn, Ru, Rh, Pd, Pt, etc. The preferred component is a high entropy alloy of CoNiRuRhPd.

[0098] In a preferred embodiment, the molar ratio of the high entropy alloy and SrTiO3 supported in the catalyst is 0.005 to 0.1: 1. Preferably, the molar ratio of the high entropy alloy and SrTiO3 supported in the catalyst is 0.05:1.

[0099] In a preferred embodiment, the illumination intensity of the illumination condition is 10-5000 mW / cm 2 The preferred light intensity is 4000mW / cm 2 .

[0100] In a preferred embodiment, the light source used for the lighting conditions is one or more selected from natural light, a xenon lamp, an LED lamp, a tungsten lamp and a mercury lamp.

[0101] In a preferred embodiment, the reaction temperature is 20-600° C. Preferably, the reaction temperature is 25° C.

[0102] The reaction lasts for 0-200 hours. Preferably, the reaction lasts for 100 hours.

[0103] In a preferred embodiment, the reactor is a quartz reactor, a glass reactor, a fixed bed reactor or a mobile phase reactor. Preferably, the reactor is a mobile phase reactor.

[0104] In a preferred embodiment, the pressure of CH4 gas and CO2 gas in the reactor is 0.1 MPa to 10 MPa. Preferably, the pressure of CH4 gas and CO2 gas in the reactor is 0.1 MPa.

[0105] The method of the present invention can produce synthesis gas with high efficiency, high selectivity and high stability, wherein the conversion rate of CH4 and CO2 is above 50% overall, and the yield of synthesis gas is above 10 mol g -1 h -1 The overall selectivity is above 0.9, and there are no hydrocarbon and alcohol products. It can be directly used for Fischer-Tropsch synthesis to produce high-value hydrocarbons and oil chemicals. The catalyst has high stability and can run stably for more than 100 hours without catalyst sintering and carbon deposition. In addition, the catalyst can also drive ethane dry reforming and propane dry reforming to produce synthesis gas.

[0106] The high entropy alloy catalyst developed by the present invention has a good photothermal conversion efficiency and can drive the DRM technology to produce synthesis gas under mild conditions. This process not only helps to alleviate the greenhouse effect but also improves energy utilization efficiency, greatly reducing production costs and energy consumption.

[0107] In addition, the method of the present invention has the advantages of simple reaction process, short cycle, cheap and easily available catalyst and reusable, wide source of reactant raw materials, especially the direct use of combustible ice, shale gas and natural gas as raw gas, etc., which provides a new synthesis route for the preparation of synthesis gas by DRM reaction and has broad industrial application prospects.

[0108] Furthermore, after in-depth research by the present invention, catalyst carriers with strong CO2 adsorption capacity are preferably selected, including but not limited to titanate materials (SrTiO3, Sr x Ba 1-x TiO3, SrBaTiO3, CaTiO3 and SrZrO3, etc.) and oxide materials (TiO2, CeO2, ZnO, Al2O3, MgO, SiO2, etc.). High entropy alloy catalysts with strong CH bond and C=O bond dissociation ability and strong photothermal conversion ability were screened out. The components of high entropy alloys include but are not limited to Co, Ni, Cu, Zn, Ru, Rh, Pd, Pt, etc. Using supported high entropy alloy catalysts, efficient, highly selective and highly stable DRM preparation of synthesis gas was achieved under focused sunlight.

[0109] The method for preparing synthesis gas by photothermal driven DRM reaction of the present invention comprises: using SrTiO3 loaded high entropy alloy as a catalyst, in a flow reactor, under the irradiation of focused sunlight, converting two equal volumes of greenhouse gases (CH4 and CO2 gases) into equal volumes of synthesis gas at room temperature.

[0110] In the method of the present invention, after the reaction is completed, the only product is synthesis gas, which does not require additional separation steps and can be directly used for Fischer-Tropsch synthesis to produce high-value chemicals.

[0111] In the method of the present invention, after the reaction is completed, the conversion rate of the raw gas CH4 and CO2 and the generation rate and selectivity of the product synthesis gas can be detected by conventional means, such as but not limited to using gas chromatography GC. The stability of the catalyst can be detected by long-term operation under working conditions.

[0112] In the method of the present invention, commercial SrTiO3 can be directly purchased as a catalyst carrier, or a SrTiO3 carrier with a specific structure can be synthesized according to experimental requirements. The metal salt used can be one or more of nitrate, chloride, and acetate.

[0113] In the method of the present invention, the catalyst used is the SrTiO3 compound loaded by high entropy alloy. In the catalyst of the present invention, SrTiO3 as basic material is not only widely available and cheap, but also has very excellent optical properties, chemical stability, thermal stability, super hydrophilicity and non-migration. Meanwhile, the inventor has found that in the preparation process of the catalyst, by simply loading high entropy alloy, the SrTiO3 compound loaded by the high entropy alloy obtained can be used as an efficient catalyst to convert CH4 and CO2 gas or CH4 and CO2 in gas into synthesis gas with high selectivity under specific reaction conditions. In addition, the inventor has also found that the SrTiO3 catalyst loaded by the high entropy alloy used has good stability, can be stably operated for more than 100h under working conditions, thus making the whole process of the present invention have great industrial application prospects.

[0114] In the method of the present invention, preferably, the molar ratio of the high entropy alloy and SrTiO3 loaded in the catalyst is 0.05:1.

[0115] In the method of the present invention, the raw gas used may be in the form of pure CH4 and CO2 gas, or in the form of gas containing CH4 and CO2. The term "gas containing CH4 and CO2" refers to a gas mixture containing CH4 and CO2. In addition, the raw gas may also be directly derived from combustible ice, shale gas and natural gas. Preferably, the gas containing CH4 and CO2 gas has a volume content greater than 10%.

[0116] In the method of the present invention, although there is no particular limitation on the pressure of CH4 and CO2 gases or gases containing CH4 and CO2 in the reactor, preferably, the pressure of CH4 and CO2 gases or gases containing CH4 and CO2 in the reactor is 0.1 MPa.

[0117] In the method of the present invention, preferably, the illumination intensity of the illumination conditions used can be 10-5000 mW / cm 2 The preferred light intensity is 4000mW / cm 2 .

[0118] In the method of the present invention, there is no particular limitation on the light source used for the illumination condition, as long as it can emit light radiation. Preferably, the light source used for the illumination condition can be one or more selected from focused sunlight, a xenon lamp, an LED lamp (i.e., a light emitting diode), a tungsten lamp, and a mercury lamp.

[0119] In the method of the present invention, the reaction temperature of the reactor is generally 20-600° C.; preferably, the reaction temperature used can be 20-600° C., and most preferably, the reaction is carried out at room temperature (i.e., about 25-30° C.). When necessary, the reactor can be heated to the desired reaction temperature by conventional means such as electric heating wires or heating jackets.

[0120] In the method of the present invention, from the perspective of efficiency, the reaction can usually be stably operated for 0-200 hours, and the more preferred operating time is 100 hours.

[0121] In the method of the present invention, there is no particular limitation on the reactor used, as long as it is a container that can withstand a certain pressure and can be sealed. For example, the reactor used can be a quartz reactor, a glass reactor, a fixed bed reactor or a flow reactor.

[0122] In the method of the present invention, the catalyst carrier used is not particularly limited, and the catalyst carrier used is not limited to SrTiO3. Other commercial oxides can also be used instead of SrTiO3, such as titanate materials (Sr x Ba 1-x TiO3, SrBaTiO3, CaTiO3 and SrZrO3, etc.) and oxide materials (TiO2, CeO2, ZnO, Al2O3, MgO, SiO2, etc.). Commercial SrTiO3 is preferred as the carrier.

[0123] In the method of the present invention, the high entropy alloy used is not particularly limited, and the components of the high entropy alloy include but are not limited to Co, Ni, Cu, Zn, Ru, Rh, Pd, Pt, etc. The preferred component is a high entropy alloy of CoNiRuRhPd.

[0124] The above content of the present invention provides the use of a loaded high entropy alloy as a catalyst in the preparation of synthesis gas by dry reforming of a CO2 source and a light alkane source, and a method for preparing synthesis gas by photothermal driven dry reforming of methane. The present invention applies a loaded high entropy alloy as a catalyst in the process of preparing synthesis gas by dry reforming of a CO2 source and a light alkane source, and also discloses a corresponding efficient and sustainable photothermal driven dry reforming (DRM) of methane to prepare synthesis gas (CO and H2). The present invention utilizes a high entropy alloy loaded on a metal oxide carrier or a titanate carrier as a catalyst, and in a flow reactor, under external energy (such as focused sunlight irradiation), two greenhouse gases (CH4 and CO2 gases) are converted into an equal volume of synthesis gas under mild conditions. The product synthesis gas can be directly used for Fischer-Tropsch synthesis to manufacture high-value chemicals.

[0125] The specific supported high entropy alloy catalyst used in the present invention has a good photothermal conversion efficiency, and can realize the DRM technology to prepare synthesis gas under mild conditions. This process not only helps to alleviate the greenhouse effect but also improves the efficiency of energy utilization, greatly reducing production costs and energy consumption. In addition, the method of the present invention has the advantages of simple reaction process, short cycle, cheap and easy to obtain catalysts and reusable, wide sources of reactant raw materials, especially can directly use combustible ice, shale gas and natural gas as raw gas, etc., providing a new synthesis route for DRM to prepare synthesis gas, and has broad industrial application prospects.

[0126] The high entropy alloy catalyst used in the present invention has a good photothermal conversion efficiency, can drive the DRM technology to prepare synthesis gas under mild conditions, and is efficient, highly selective, and highly stable in producing synthesis gas, without hydrocarbon and alcohol products, and can be directly used for Fischer-Tropsch synthesis to produce high-value hydrocarbons and oil chemicals; the catalyst has high stability and can be stably operated for more than 100 hours without catalyst sintering and carbon deposition; in addition, the catalyst can also drive ethane dry reforming and propane dry reforming to prepare synthesis gas. This process not only helps to alleviate the greenhouse effect but also improves energy utilization efficiency, greatly reducing production costs and energy consumption. In addition, the method provided by the present invention has the advantages of simple reaction process, short cycle, cheap and easy to obtain catalyst and reusable, wide sources of reactant raw materials, especially can directly use combustible ice, shale gas and natural gas as raw gas, etc., providing a new synthesis route for DRM reaction to prepare synthesis gas, and has broad industrial application prospects.

[0127] The experimental results show that the method for preparing synthesis gas by dry reforming provided by the present invention can convert two equal volumes of greenhouse gases (CH4 and CO2 gases) into equal volumes of synthesis gas at room temperature by only using focused sunlight in a mobile phase reactor. The conversion rates of CH4 and CO2 are generally above 50%, and the yield of synthesis gas is above 10 mol g -1 h -1The overall selectivity is above 0.9, there are no hydrocarbon and alcohol products, and the catalyst can operate stably for more than 100 hours.

[0128] In order to further illustrate the present invention, the application of the loaded high entropy alloy provided by the present invention as a catalyst in the preparation of synthesis gas by dry reforming of CO2 source and light alkane source and a method for preparing synthesis gas by dry reforming of light alkane are described in detail below in combination with the embodiments. However, it should be understood that these embodiments are implemented on the premise of the technical scheme of the present invention, and detailed implementation methods and specific operating processes are given only to further illustrate the features and advantages of the present invention, rather than to limit the claims of the present invention, and the protection scope of the present invention is not limited to the following embodiments.

[0129] Catalyst preparation

[0130] The catalyst used in the present invention is prepared as follows, taking SrTiO3 loaded with a high entropy alloy as an example:

[0131] 2.3 g of commercial SrTiO3 and 100 mL of deionized water were added to a 500 mL glass beaker. After vigorous stirring for 30 min, 5 mL of 10 mM solution of each metal precursor was added. After stirring at room temperature for 1 hour, the resulting mixture was evaporated at 100 ° C overnight to completely remove the deionized water. Then, the resulting sample was calcined at 400 ° C for 2 hours in a 10% H2 / 90% Ar atmosphere (heating rate 5 ° C min -1 ). Finally, the mixture was cooled naturally to room temperature, thereby obtaining a high entropy alloy-supported SrTiO3 catalyst. The molar ratio of the high entropy alloy supported in the catalyst to SrTiO3 was 0.05:1.

[0132] Based on the same procedure as above, only the amount of the metal precursor used is changed accordingly, thereby obtaining a molar ratio of SrTiO3 loaded on the high entropy alloy of 0.005 to 0.1:1.

[0133] Based on the same procedure as above, only the amount of the metal precursor used is changed accordingly, thereby obtaining a molar ratio of SrTiO3 loaded on the high entropy alloy of 0.005 to 0.1:1.

[0134] Based on the same procedure as above, just change the type of metal precursor used accordingly to obtain SrTiO3 catalysts loaded with different high entropy alloys, including but not limited to CoNiCuPdRu / SrTiO3, CoNiCuPdRh / SrTiO3, CoNiCuPdPt / SrTiO3, CoNiCuPdAu / SrTiO3, CoNiCuPtRu / SrTiO3, CoNiCuRhRu / SrTiO3 and the like.

[0135] Based on the same procedure as above, by using Sr x Ba 1-x Titanate materials such as TiO3, SrBaTiO3, CaTiO3 and SrZrO3, and oxide materials such as TiO2, CeO2, ZnO, Al2O3, MgO, SiO2, etc. are used instead of SrTiO3 as carrier materials to prepare other high entropy alloy supported catalysts with the same metal loading.

[0136] Example 1

[0137] In the mobile phase reactor (the reactor is connected by a stainless steel valve and can apply a maximum pressure of 20MPa), 5mg of high entropy alloy-supported SrTiO3 catalyst (CoNiRuRhPd / SrTiO3, where the molar ratio of CoNiRuRhPd and SrTiO3 is 0.05:1) is added as a catalyst, and a steel cylinder containing 10% CH4 / 10% CO2 / 80Ar is introduced into the mobile phase reactor through a pressure reducing valve. The pressure in the reactor is atmospheric pressure, and the flow rates of CH4 and CO2 are 10mLmin each. -1 , the total flow rate is 20mLmin -1 At room temperature (about 25°C), using focused sunlight as the light source, at 4000mW / cm 2 The reaction was carried out under irradiation with a light intensity of

[0138] The product syngas was evaluated by an online gas chromatograph (GC-2014ATFSPL, Ar carrier, Shimadzu) equipped with two flame ionization detectors (FIDs) and one thermal conductivity detector (TCD).

[0139] See also Figure 1 , Figure 1 The synthesis gas yield rate and selectivity obtained in the dry reforming of methane provided in Example 1 of the present invention. Figure 1 a is the conversion rate of CO, Figure 1 b is selectivity.

[0140] Depend on Figure 1 It can be seen that the products determined by gas chromatography are CO and H2, and the generation rate of CO and H2 is 10 molg -1 h -1 Above, the conversion rate of CH4 and CO2 is above 50% ( Figure 1 a), the selectivity of synthesis gas is above 0.9 ( Figure 1 b). In addition, the catalyst can operate continuously and stably for more than 100 hours. Combined with the syngas generation rate, selectivity and catalyst stability, it has obvious potential for industrial application.

[0141] Example 2

[0142] The specific reaction process and detection method are the same as those in Example 1, and CoNiRuRhPd / BaTiO3 is used instead of CoNiRuRhPd / SrTiO3 as the catalyst.

[0143] The production rate of the target product synthesis gas was 8.0 molg -1 h -1 , the selectivity is 0.92.

[0144] Example 3

[0145] The specific reaction process and detection method are the same as those in Example 1. x Ba 1-x TiO3 replaces CoNiRuRhPd / SrTiO3 as catalyst.

[0146] The production rate of the target product synthesis gas was 9.0 molg -1 h -1 , the selectivity is 0.95.

[0147] Example 4

[0148] The specific reaction process and detection method are the same as those in Example 1, and CoNiRuRhPd / CaTiO3 is used instead of CoNiRuRhPd / SrTiO3 as the catalyst.

[0149] The production rate of the target product synthesis gas was 6.3 molg -1 h -1 , the selectivity is 0.91.

[0150] Example 5

[0151] The specific reaction process and detection method are the same as those in Example 1, and CoNiRuRhPd / SrZrO3 is used instead of CoNiRuRhPd / SrTiO3 as the catalyst.

[0152] The production rate of the target product synthesis gas is 5.0 molg -1 h -1 , the selectivity is 0.90.

[0153] Example 6

[0154] The specific reaction process and detection method are the same as those in Example 1, except that CoNiRuRhPd / MgO is used instead of CoNiRuRhPd / SrTiO3 as the catalyst.

[0155] The production rate of the target product synthesis gas was 1.2 molg -1 h-1 , the selectivity is 0.70.

[0156] Example 7

[0157] The specific reaction process and detection method are the same as those in Example 1, and CoNiRuRhPd / Al2O3 is used instead of CoNiRuRhPd / SrTiO3 as the catalyst.

[0158] The production rate of the target product synthesis gas was 1.6 molg -1 h -1 , the selectivity is 0.75.

[0159] Example 8

[0160] The specific reaction process and detection method are the same as those in Example 1, and a 300 xenon lamp is used as the light source instead of natural sunlight.

[0161] The production rate of the target product synthesis gas was 9.8 molg -1 h -1 , the selectivity is 0.95.

[0162] Example 9

[0163] The specific reaction process and detection method are the same as those in Example 1, using 50% CH4 / 50% CO2 instead of 10% CH 4 / 10% CO2 / 80% Ar was used as the raw gas.

[0164] The production rate of the target product synthesis gas is 20 molg -1 h -1 , the selectivity is 0.50.

[0165] Example 10

[0166] The specific reaction process and detection method are the same as those in Example 1, using 1% CH4 / 1% CO2 / 98% Ar instead of 10% CH4 / 10% CO2 / 80% Ar as the raw gas.

[0167] The production rate of the target product CO was 0.3 mol g -1 h -1 , the selectivity is 1.0.

[0168] Embodiment 11

[0169] The specific reaction process and detection method are the same as those in Example 1, except that 50 mL min -1 The flow rate is 20 mL / min. -1 Flow rate.

[0170] The production rate of the target product synthesis gas is 19 molg -1 h -1 , the selectivity is 0.52.

[0171] Example 12

[0172] The specific reaction process and detection method are the same as those in Example 1, except that 5 mL min -1 The flow rate is 20 mL / min. -1 Flow rate.

[0173] The production rate of the target product synthesis gas was 3.3 molg -1 h -1 , the selectivity is 1.0.

[0174] Examples 13 to 23

[0175] The specific reaction process and detection method were the same as those in Example 1. A batch reactor was used instead of a mobile phase reactor for the experiment. The recovered catalyst was used 1, 2, 3, up to 11 times (i.e., it was reused 10 times).

[0176] See also Figure 2 , Figure 2 The results are the reusability performance results of the SrTiO3-loaded high entropy alloy catalyst provided by the present invention.

[0177] Depend on Figure 2 It can be seen that the catalytic efficiency (ie, the activity and selectivity of the target product) of the catalyst of the present invention does not decrease significantly after being reused 10 times.

[0178] The above is a detailed introduction to the application of the loaded high entropy alloy provided by the present invention as a catalyst in the preparation of synthesis gas by dry reforming of CO2 source and light alkane source, and a method for preparing synthesis gas by photothermal driven dry reforming of methane. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enables any technician in the field to practice the present invention, including the manufacture and use of any device or system, and the implementation of any combined method. It should be pointed out that for ordinary technicians in the field of technology, without departing from the principles of the present invention, the present invention can also be improved and modified in several ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements that are not different from the text of the claims, or if they include equivalent structural elements that are not substantially different from the text of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. Application of supported high entropy alloy as catalyst in the preparation of synthesis gas by dry reforming of CO2 source and light alkane source; The metals in the high entropy alloy include five or more of Co, Ni, Cu, Zn, Ru, Rh, Pd and Pt; The preparation conditions include preparing under energizing conditions; The energizing method includes illumination and / or heating.

2. The use according to claim 1, characterized in that: The supported carrier includes an oxide carrier and / or a titanate carrier; The light alkanes include methane, ethane or propane.

3. The use according to claim 2, characterized in that: The molar ratio of the high entropy alloy to the carrier is (0.005-0.1):1; The oxide carrier includes one or more of TiO2, CeO2, CaO, ZnO, Al2O3, MgO and SiO2; The titanate carrier includes SrTiO3, Sr x Ba 1-x One or more of TiO3, SrBaTiO3 and CaTiO3; wherein 0<x<1.

4. The use according to claim 3, characterized in that: The preparation time is 0.1 to 300 h; The illumination intensity of the illumination is 10-5000 mW / cm 2 .

5. The use according to claim 4, characterized in that: The light source of the illumination includes one or more of natural light, xenon lamp, LED lamp, tungsten lamp and mercury lamp; The temperature of the illumination is room temperature; The heating temperature is 100-700°C.

6. The use according to claim 1, characterized in that: The CO2 source includes CO2 or a gas containing CO2; The light alkane source includes light alkanes or gases containing light alkanes; The CO2 source and the light alkane source include a mixed gas of CO2 and light alkanes or a mixed gas containing CO2 and light alkanes; The molar ratio of the metal elements in the high entropy alloy is 1:

1.

7. A method for preparing synthesis gas by dry reforming of light alkanes, characterized in that: The following steps are involved: Under the condition of energy, CO2 source and light alkane source are subjected to methane dry reforming reaction under the action of supported catalyst loaded with high entropy alloy to obtain CO and H2; The metals in the high entropy alloy include five or more of Co, Ni, Cu, Zn, Ru, Rh, Pd and Pt; The energizing method includes illumination and / or heating.

8. The method according to claim 7, characterized in that The molar ratio of the high entropy alloy to the loaded carrier is (0.005-0.1):1; The support includes an oxide support and / or a titanate support.

9. The method according to claim 7, characterized in that: The pressure of the CO2 source is 0.1~10 MPa; The pressure of the light alkane source is 0.1-10 MPa.

10. The method according to claim 8, characterized in that The illumination intensity of the illumination is 10-5000 mW / cm 2 ; The heating temperature is 100-700°C; The preparation time is 0.1 to 300 h; The reactor for performing the methane dry reforming reaction includes one or more of a quartz reactor, a glass reactor, a fixed bed reactor and a mobile phase reactor.

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