Application of aluminum-based alloy material in photocatalytic synthesis of ammonia reaction

Abstract

This invention relates to the application of an aluminum-based alloy material in the photocatalytic ammonia synthesis reaction. The invention prepares an aluminum-based alloy material by reacting Al with metal M at a specific heat treatment temperature, and for the first time applies this material to the photocatalytic ammonia synthesis reaction. On one hand, it utilizes the electronic regulation effect of aluminum on metal M to promote the adsorption and activation of N2 molecules by metal M; on the other hand, it utilizes aluminum as a second active site to capture nitrogen species overflowing from metal M under illumination, forming weak adsorption sites that promote subsequent hydrogenation and the desorption of the product NH3. This dual-site catalytic strategy cleverly avoids the scaling relationship in ammonia synthesis, greatly enhancing catalytic activity. Furthermore, this invention selects a specific metal M with strong binding ability to N2 molecules, utilizing its ability to promote N2 molecule activation, which is beneficial to the ammonia synthesis reaction, thereby significantly improving the catalytic activity of the aluminum-based alloy material.

Description

Technical Field

[0001] This invention belongs to the field of new material applications and relates to the application of an aluminum-based alloy material in the photocatalytic synthesis of ammonia. Background Technology

[0002] The ammonia synthesis industry plays a vital role in national economic and social development. Traditional ammonia synthesis relies primarily on the Haber-Bosch process, involving high-temperature and high-pressure reaction conditions, inevitably leading to high energy consumption and carbon emissions. Photocatalysis, as an emerging reaction pathway, can achieve nitrogen activation under mild conditions and has attracted widespread attention in the ammonia synthesis field. Currently, photocatalyst design mainly focuses on the preparation of semiconductor materials. However, semiconductors have very limited utilization of the full-spectrum solar spectrum, and the rapid electron-hole recombination and slow surface reaction kinetics severely affect the reaction efficiency of traditional photocatalysis, resulting in low ammonia synthesis efficiency. Combining thermocatalysis and photocatalysis, utilizing thermally driven photo-excited N2 molecules to form photothermal synergistic catalysis, would significantly reduce the reaction energy barrier and circumvent the difficulty of N2 molecule activation at low temperatures with traditional iron-based catalysts. Furthermore, another problem with traditional iron-based catalysts is the limitation imposed by scaling relations; the Fe-N bonds are too strong, making it difficult for product molecules to desorb from the catalyst surface. Therefore, based on the photothermal synergistic pathway, how to bypass the scaling relationship and develop a highly efficient ammonia synthesis catalyst that can simultaneously promote N2 activation and NH3 desorption under mild conditions has become a major challenge. Summary of the Invention

[0003] This invention addresses the challenges of low-temperature N2 activation and NH3 desorption of traditional Fe-based catalysts by providing an application of aluminum-based alloy materials in photocatalytic ammonia synthesis.

[0004] The objective of this invention can be achieved through the following methods: This invention provides an application of aluminum-based alloy materials in the photocatalytic synthesis of ammonia.

[0005] As one embodiment of the present invention, the reaction is a gas-solid phase ammonia synthesis reaction.

[0006] As one embodiment of the present invention, the application is to use aluminum-based alloy materials as catalysts in photocatalytic ammonia synthesis reaction, including the following steps: loading aluminum-based alloy materials into a reactor, introducing reactant gases, and carrying out photocatalytic ammonia synthesis reaction under light conditions, thereby obtaining the product.

[0007] Furthermore, the amount of aluminum-based alloy material used in the photocatalytic ammonia synthesis reaction is 1~500 mg, preferably 50~200 mg.

[0008] Furthermore, the nitrogen source in the reactant gas is nitrogen gas, and the hydrogen source is hydrogen gas.

[0009] Furthermore, the gas flow rate of the reactant gas is 1~100 mL / min. -1 Preferably, the concentration is 20-80 mL / min. -1 The flow rate ratio of hydrogen to nitrogen is 0.1:1 to 10:1, preferably 0.5:1 to 4:1, and more preferably 3:1.

[0010] Furthermore, the pressure reaction conditions in the photocatalytic ammonia synthesis reaction are 0.1~1 MPa, preferably 0.1~0.5 MPa.

[0011] Furthermore, the photocatalytic ammonia synthesis reaction is carried out at a temperature of 320-360℃ for a time of 25-35 min, preferably 30 min.

[0012] Furthermore, the light source in the illumination conditions includes one of a full-spectrum xenon lamp, an LED, or a high-intensity monochromatic laser; the illumination intensity is 1~50 W cm⁻¹. -2 Preferably 2~10 W cm -2 .

[0013] Furthermore, after the photocatalytic ammonia synthesis reaction, the gas is passed into a sulfuric acid solution to collect NH4. + The sample was then detected using ion chromatography.

[0014] Furthermore, the concentration of the sulfuric acid solution is 1~10 mM, preferably 2~6 mM.

[0015] In one embodiment of the present invention, the aluminum-based alloy material is composed of Al and metal M; metal M is selected from one or more of Fe, Co, Ni, Mo, and Ru, and the mass fraction of metal M in the aluminum-based alloy material is 5-20%. If the mass fraction of metal element M is too low, there will be insufficient active sites and low catalytic activity; while if the mass fraction of metal M is too high, it will lead to particle agglomeration, larger size, which is not conducive to the dispersion of active sites and reduces the overall activity. Preferably, when the mass ratio of Al to metal M is close to 10:1, the catalyst exhibits better photocatalytic ammonia synthesis performance.

[0016] Furthermore, the aluminum-based alloy material includes binary, ternary, quaternary, and multi-component aluminum-based alloy materials. Specifically, the number and types of metal elements in the aluminum-based alloy material are not necessarily related to the final catalytic activity; it mainly depends on the contribution of the intrinsic properties of each metal element to the overall catalytic reaction, involving the adsorption and activation of N2 molecules, the adsorption and activation of H2 molecules, the hydrogenation of active nitrogen species, and the desorption of NH3 molecules. Preferably, the aluminum-based alloy material is a ternary aluminum-based alloy material; wherein, metal M is Mo and Ni. In this case, the catalytic activity of the aluminum-based alloy material is further enhanced.

[0017] Furthermore, the aluminum-based alloy material consists of two parts: one part is unalloyed aluminum particles used as a carrier, and the other part is Al formed by the alloying of Al and metallic M. x M y Alloy, thus forming Al x M y / Al aluminum-based alloy materials.

[0018] Furthermore, the aluminum-based alloy material is prepared by the following method: S1. Using aluminum particles as a carrier, a metal M salt is modified on its surface to obtain a surface-modified aluminum-based material. S2. Heat-treat the aluminum-based material with surface modification in step S1 to obtain an aluminum-based alloy material.

[0019] Furthermore, in step S1, the aluminum particles are micron-sized aluminum particles.

[0020] Further, in step S1, the metal M salt includes one or more of chloride salts, nitrate salts, sulfate salts, carbonate salts, acetylacetone salts, carbonyl salts, acetate salts, or other organic salts.

[0021] Further, in step S1, the method for surface modification with metal M salt includes any one of the following methods A and B: Method A: Mix aluminum particles with metallic M salt and grind or ball mill them; Method B: Disperse aluminum particles and metal M salt in a solvent, stir to react, and centrifuge.

[0022] Further, in method A, the mixing and grinding or ball milling time is 5~300 min, preferably 30~120 min. Aluminum particles are mixed and ground or ball-milled with metallic M salt (MX) particles to obtain aluminum (MX-Al) modified with metallic salt particles. Mixing without grinding or ball milling will not result in a reaction.

[0023] Furthermore, in method B, the stirring reaction time is greater than 0 h, preferably 0.5 to 24 h, and more preferably 10 to 20 h.

[0024] Furthermore, in method B, the solvent is an aprotic solvent selected from one or more of toluene, hexane, cyclohexane, methylcyclohexane, 1,4-dioxane, tetrahydrofuran, and dichloromethane, preferably tetrahydrofuran.

[0025] Further, in step S2, the heat treatment temperature is 400-550 °C, and the reaction time is preferably 0.5-24 h; the heating rate of the heat treatment is arbitrary, preferably 0.5-10 °C / min. -1 When the metal M salt is selected from chloride, nitrate, sulfate, carbonate, acetate, etc., the heat treatment temperature is 300-450℃; when the metal M salt is selected from acetylacetone salt, carbonyl salt, etc., the heat treatment temperature is 300-550℃.

[0026] Furthermore, the heat treatment is carried out in a non-oxidizing atmosphere, including one or more of argon, nitrogen, and hydrogen. The heat treatment can be performed under negative pressure, atmospheric pressure, or high pressure conditions. The purpose of heat treatment is to promote Al diffusion and alloying.

[0027] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention prepares an aluminum-based alloy material by reacting Al with metal M at a specific heat treatment temperature, and for the first time applies this aluminum-based alloy material to the photocatalytic ammonia synthesis reaction. On one hand, it utilizes the electronic regulation effect of aluminum on metal M to promote the adsorption and activation of N2 molecules by metal M; on the other hand, it utilizes aluminum as a second active site to capture nitrogen species overflowing from metal M under illumination, forming weak adsorption sites that promote subsequent hydrogenation and the desorption of the product NH3. This dual-site catalytic strategy cleverly avoids the scaling relationship in ammonia synthesis, greatly enhancing catalytic activity. Furthermore, this invention selects a specific metal M with strong binding ability to N2 molecules, utilizing its ability to promote N2 molecule activation, which is beneficial to the ammonia synthesis reaction, thereby significantly improving the catalytic activity of the aluminum-based alloy material.

[0028] 2. The aluminum-based alloy material prepared by this invention utilizes a photothermal synergistic strategy to significantly reduce the activation energy barrier of N2 molecules. Furthermore, it promotes the desorption of product molecules from the catalyst surface through photoinduced nitrogen overflow, cleverly avoiding the scaling relationship in ammonia synthesis, greatly improving the efficiency of photocatalytic ammonia synthesis, and showing potential industrial application prospects.

[0029] 3. The aluminum-based alloy material prepared by this invention can convert nitrogen (N2) and hydrogen (H2) into ammonia (NH3) under normal pressure and light irradiation without additional heat input, exhibiting excellent photocatalytic activity at temperatures below 5 W / cm². -2Under light intensity, its activity far exceeds that of current industrial ammonia synthesis catalysts, representing the highest ammonia synthesis catalytic activity reported to date. Attached Figure Description

[0030] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 These are the XRD patterns of AlFe / Al and Fe / Al prepared in Example 1 and Comparative Example 1; Figure 2 These are the photocatalytic ammonia synthesis performance test graphs of AlFe / Al and Fe / Al prepared in Example 1 and Comparative Example 1; Figure 3 This is the XRD pattern of the AlMo alloy prepared in Example 2 loaded on Al (AlMo / Al); Figure 4 This is the XRD pattern of the AlNi alloy prepared in Example 3 loaded on Al (AlNi / Al); Figure 5 This is the XRD pattern of the AlMoNi alloy prepared in Example 4 loaded on Al (AlMoNi / Al); Figure 6 These are the photocatalytic ammonia synthesis performance test graphs of AlMo / Al, AlNi / Al, and AlMoNi / Al prepared in Examples 2-4; Figure 7 These are the photocatalytic ammonia synthesis performance test graphs of AlCo / Al, AlRu / Al, and Cu / Al prepared in Examples 5, 6, and Comparative Example 2; Figure 8 This is a schematic diagram illustrating the working principle of photocatalytic ammonia synthesis using aluminum-based alloy materials according to the present invention. Detailed Implementation

[0031] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The following examples are implemented under the premise of the technical solution of the present invention, providing detailed implementation methods and specific operating procedures, which will help those skilled in the art to further understand the present invention. It should be noted that the scope of protection of the present invention is not limited to the following embodiments; any adjustments and improvements made under the concept of the present invention are all within the scope of protection of the present invention.

[0032] Example 1 1. Preparation of AlFe alloy supported on Al materials Weigh 32 mg Fe2(CO)9 and 90 mg Al and disperse them in 5 mL of dehydrated tetrahydrofuran. Stir for 12 h, then place on a fixed bed and purge with H2 (5 mL min). -1), at 0.5 ℃ min -1 The heating rate was set at 250 °C for 2 h, then increased at 5 °C per minute. -1 The temperature was increased to 550 °C at a heating rate and held for 12 h to obtain Al material supported on AlFe nanoalloys, denoted as AlFe / Al.

[0033] 2. Performance testing of AlFe / Al photocatalytic ammonia synthesis 100 mg of the AlFe / Al catalyst prepared in Example 1 was weighed and loaded into a quartz reactor on a fixed bed. Reactant gases N2 and H2 were then introduced, with their flow rates controlled at 15 mL / min. -1 and 45 mL min -1 Then turn on the xenon lamp and adjust the light intensity to 4.28 W cm. -2 The equivalent temperature was maintained at 360 °C and the pressure at 0.1 MPa. Pretreatment was performed under these conditions for half an hour. The reacted gas was then passed into a 5 mM sulfuric acid solution, and the NH4 produced was collected at intervals. + The NH4 collected during this period was then analyzed using ion chromatography. + The concentration was used to calculate the yield of photocatalytic ammonia synthesis using the external standard method.

[0034] Comparative Example 1 1. Preparation of Fe nanoparticles supported on Al materials Weigh 32 mg Fe2(CO)9 and 90 mg Al and disperse them in 5 mL of dehydrated tetrahydrofuran. Stir for 12 h, then place on a fixed bed and purge with H2 (5 mL min). -1 ), at 0.5 ℃ min -1 By adjusting the heating rate and holding at 250 °C for 2 h, Fe nanoparticle-supported Al material was obtained, denoted as Fe / Al.

[0035] 2. Performance testing of Fe / Al photocatalytic ammonia synthesis 100 mg of the Fe / Al catalyst prepared in Example 1 was weighed and loaded into a quartz reactor on a fixed bed. Then, reactant gases N2 and H2 were introduced, with their flow rates controlled at 15 mL / min. -1 and 45 mL min -1 Then turn on the xenon lamp and adjust the light intensity to 4.28 W cm. -2 The equivalent temperature was maintained at 360 °C and the pressure at 0.1 MPa for half an hour under these conditions. The reacted gas was then passed into a 5 mM sulfuric acid solution, and the NH4 produced was collected at intervals. + The NH4 collected during this period was then tested using ion chromatography.+ The concentration was used to calculate the yield of photocatalytic ammonia synthesis using the external standard method.

[0036] The experimental results from Example 1 and Comparative Example 1 were characterized as follows: The prepared AlFe / Al and Fe / Al were characterized by XRD. Figure 1 It can be seen that, compared with the XRD of pure Fe / Al, the diffraction peak position of Fe (110) crystal plane in AlFe / Al is shifted to a lower angle (2θ = 43.5 °), indicating that Al was successfully incorporated into the Fe lattice, causing the Fe lattice to expand, which proves the formation of AlFe alloy on Al substrate.

[0037] The prepared AlFe / Al and Fe / Al were subjected to photocatalytic ammonia synthesis activity tests. Figure 2 It can be seen that the Fe / Al without alloy formation is at 4.28 W / cm². -2 The ammonia synthesis activity under light intensity was only 0.021 mmol g. -1 h -1 After alloying, under the same conditions, its photocatalytic ammonia synthesis activity reached 8.6 mmol g. -1 h -1 This indicates that Al and Fe in the alloy synergistically promote the enhancement of catalytic activity.

[0038] Example 2 1. Preparation of AlMo alloy supported on Al materials Weigh 32 mg of molybdenum acetylacetonate and 90 mg of Al and disperse them in 5 mL of ultradehydrated tetrahydrofuran. Stir for 12 h, then place on a fixed bed and purge with H2 (5 mL min). -1 ), at 0.5 ℃ min -1 The heating rate was set at 250 °C for 2 h, then increased at 5 °C per minute. -1 The temperature was increased to 400 °C at a heating rate and held for 12 h to obtain Al material supported on AlMo nanoalloys, denoted as AlMo / Al.

[0039] 2. Performance testing of AlMo / Al photocatalytic ammonia synthesis 100 mg of the AlMo / Al catalyst prepared in Example 2 was weighed and loaded into a quartz reactor on a fixed bed. Reactant gases N2 and H2 were then introduced, with their flow rates controlled at 15 mL / min. -1 and 45 mL min -1 Then turn on the xenon lamp and adjust the light intensity to 3.48 W cm⁻¹. -2The equivalent temperature was maintained at 320 °C and the pressure at 0.1 MPa for half an hour under these conditions. The reacted gas was then passed into a 5 mM sulfuric acid solution, and the NH4 produced was collected at intervals. + The NH4 collected during this period was then tested using ion chromatography. + The concentration was used to calculate the yield of photocatalytic ammonia synthesis using the external standard method.

[0040] Example 3 1. Preparation of AlNi alloy supported on Al materials Weigh 44 mg of nickel acetylacetonate and 90 mg of Al and disperse them in 5 mL of ultradehydrated tetrahydrofuran. Stir for 12 h, then place on a fixed bed and purge with H2 (5 mL min). -1 ), at 0.5 ℃ min -1 The heating rate was set at 250 °C for 2 h, then increased at 5 °C per minute. -1 The temperature was increased to 400 °C at a heating rate and held for 12 h to obtain Al material supported on AlNi nanoalloy, denoted as AlNi / Al.

[0041] 2. Performance testing of AlNi / Al photocatalytic ammonia synthesis 100 mg of the AlNi / Al catalyst prepared in Example 3 was weighed and loaded into a quartz reactor on a fixed bed. Then, reactant gases N2 and H2 were introduced, with their flow rates controlled at 15 mL / min. -1 and 45 mL min -1 Then turn on the xenon lamp and adjust the light intensity to 3.48 W cm⁻¹. -2 The equivalent temperature was maintained at 320 °C and the pressure at 0.1 MPa for half an hour under these conditions. The reacted gas was then passed into a 5 mM sulfuric acid solution, and the NH4 produced was collected at intervals. + The NH4 collected during this period was then tested using ion chromatography. + The concentration was used to calculate the yield of photocatalytic ammonia synthesis using the external standard method.

[0042] Example 4 1. Preparation of AlMoNi alloy supported on Al materials Weigh 32 mg of molybdenum acetylacetonate, 9 mg of nickel acetylacetonate, and 88 mg of Al and disperse them in 5 mL of ultra-dehydrated tetrahydrofuran. Stir for 12 h, then place on a fixed bed and purge with H2 (5 mL min). -1 ), at 0.5 ℃ min -1 The heating rate was set at 250 °C for 2 hours, then increased at 5 °C per minute. -1The temperature was increased to 400 °C at a heating rate and held for 12 h to obtain Al material supported by AlMoNi ternary alloy, denoted as AlMoNi / Al.

[0043] 2. Performance testing of AlMoNi / Al photocatalytic ammonia synthesis 100 mg of the AlMoNi / Al catalyst prepared in Example 4 was weighed and loaded into a quartz reactor on a fixed bed. Reactant gases N2 and H2 were then introduced, with flow rates controlled at 15 mL / min. -1 and 45 mL min -1 Then turn on the xenon lamp and adjust the light intensity to 3.48 W cm⁻¹. -2 The equivalent temperature was maintained at 320 °C and the pressure at 0.1 MPa for half an hour under these conditions. The reacted gas was then passed into a 5 mM sulfuric acid solution, and the NH4 produced was collected at intervals. + The NH4 collected during this period was then tested using ion chromatography. + The concentration was used to calculate the yield of photocatalytic ammonia synthesis using the external standard method.

[0044] The experimental results of Examples 2, 3, and 4 were characterized as follows: Figure 3 , Figure 4 , Figure 5 XRD results for AlMo / Al, AlNi / Al, and AlMoNi / Al are presented respectively. For AlMo / Al and AlNi / Al, the diffraction peaks of the (110) crystal plane of Mo and the (111) crystal plane of Ni are shifted to lower angles, indicating that Al has been successfully incorporated into the Mo or Ni lattice, causing the Mo or Ni lattice to expand, thus proving the formation of AlMo and AlNi alloys on the Al substrate. For AlMoNi / Al, due to the low Ni content, no Ni-related XRD diffraction peaks can be observed. The diffraction peak of the (110) crystal plane of Mo in AlMoNi shifts to a higher angle, mainly because the Mo lattice contains both Al with a larger atomic radius and Ni with a smaller atomic radius, which is the result of the joint regulation of the two elements.

[0045] The photocatalytic ammonia synthesis activity of the prepared AlMo / Al, AlNi / Al, and AlMoNi / Al materials was tested. Figure 6 It can be seen that AlNi / Al is at 3.48 W cm⁻¹ -2 Under the same light intensity, almost no NH3 is generated, mainly because Ni binds very weakly to N2 molecules, failing to effectively activate them. In contrast, AlMo / Al exhibits a photocatalytic activity of 2.3 mmol / g under the same reaction conditions. -1 h -1After forming the ternary alloy, the photocatalytic activity was further enhanced to 5.2 mmol g. -1 h -1 .

[0046] Example 5 1. Preparation of AlCo alloy supported on Al materials Weigh 60 mg of cobalt acetylacetonate and 90 mg of Al and disperse them in 5 mL of ultradehydrated tetrahydrofuran. Stir for 12 h, then place on a fixed bed and purge with H2 (5 mL min). -1 ), at 0.5 ℃ min -1 The heating rate was set at 250 °C for 2 h, then increased at 5 °C per minute. -1 The temperature was increased to 400 °C at a heating rate and held for 12 h to obtain Al material supported by AlCo nanoalloys, denoted as AlCo / Al.

[0047] 2. Performance testing of AlCo / Al photocatalytic ammonia synthesis 100 mg of the AlCo / Al catalyst prepared in Example 5 was weighed and loaded into a quartz reactor on a fixed bed. Reactant gases N2 and H2 were then introduced, with their flow rates controlled at 15 mL / min. -1 and 45 mL min -1 Then turn on the xenon lamp and adjust the light intensity to 4.28 W cm. -2 The equivalent temperature was maintained at 360 °C and the pressure at 0.1 MPa for half an hour under these conditions. The reacted gas was then passed into a 5 mM sulfuric acid solution, and the NH4 produced was collected at intervals. + The NH4 collected during this period was then tested using ion chromatography. + The concentration was used to calculate the yield of photocatalytic ammonia synthesis using the external standard method.

[0048] Example 6 1. Preparation of AlRu alloy supported on Al materials Weigh 21 mg of dodecacarbonyltriruthenium and 90 mg of Al and disperse them in 5 mL of ultradehydrated tetrahydrofuran. Stir for 12 h, then place on a fixed bed and purge with H2 (5 mL min). -1 ), at 0.5 ℃ min -1 The heating rate was set at 250 °C for 2 h, then increased at 5 °C per minute. -1 The temperature was increased to 400 °C at a heating rate and held for 12 h to obtain Al material supported by AlRu nanoalloy, denoted as AlRu / Al.

[0049] 2. Performance testing of AlRu / Al photocatalytic ammonia synthesis 100 mg of the AlRu / Al catalyst prepared in Example 6 was weighed and loaded into a quartz reactor on a fixed bed. Reactant gases N2 and H2 were then introduced, with their flow rates controlled at 15 mL / min. -1 and 45 mL min -1 Then turn on the xenon lamp and adjust the light intensity to 4.28 W cm. -2 The equivalent temperature was maintained at 360 °C and the pressure at 0.1 MPa for half an hour under these conditions. The reacted gas was then passed into a 5 mM sulfuric acid solution, and the NH4 produced was collected at intervals. + The NH4 collected during this period was then tested using ion chromatography. + The concentration was used to calculate the yield of photocatalytic ammonia synthesis using the external standard method.

[0050] Comparative Example 2 1. Preparation of Cu particles supported on Al materials Weigh 41 mg of copper acetylacetonate and 90 mg of Al and disperse them in 5 mL of ultra-dehydrated tetrahydrofuran. Stir for 12 h, then place on a fixed bed and purge with H2 (5 mL min). -1 ), at 0.5 ℃ min -1 The heating rate was set at 250 °C for 2 h, then increased at 5 °C per minute. -1 The temperature was increased to 400 °C at a heating rate and held for 12 h to obtain Cu nanoparticle-supported Al material, denoted as Cu / Al.

[0051] 2. Performance testing of Cu / Al photocatalytic ammonia synthesis 100 mg of the Cu / Al catalyst prepared in Comparative Example 2 was weighed and loaded into a quartz reactor on a fixed bed. Then, reactant gases N2 and H2 were introduced, with their flow rates controlled at 15 mL / min. -1 and 45 mL min -1 Then turn on the xenon lamp and adjust the light intensity to 4.28 W cm. -2 The equivalent temperature was maintained at 360 °C and the pressure at 0.1 MPa for half an hour under these conditions. The reacted gas was then passed into a 5 mM sulfuric acid solution, and the NH4 produced was collected at intervals. + The NH4 collected during this period was then tested using ion chromatography. + The concentration was used to calculate the yield of photocatalytic ammonia synthesis using the external standard method.

[0052] The photocatalytic ammonia synthesis activity of the AlCo / Al, AlRu / Al, and Cu / Al materials prepared in Examples 5 and 6, and Comparative Example 2, was tested. Figure 7It can be seen that Cu / Al is at 4.28 W / cm². -2 Under the same light intensity, almost no NH3 is generated, mainly because Cu binds very weakly to N2 molecules, failing to effectively activate them. Meanwhile, AlCo / Al and AlRu / Al, under the same reaction conditions, exhibit photocatalytic activities of 2.5 mmol g, respectively. -1 h -1 and 3.6 mmol g -1 h -1 . In summary, this invention promotes the activation of N2 molecules by selecting a specific metal M with strong binding affinity to them, thereby facilitating the ammonia synthesis reaction. Furthermore, compared to unalloyed metal particles loaded on an aluminum support, the alloyed material exhibits higher ammonia synthesis activity. This is because, on the one hand, alloyed aluminum can modulate the electronic structure of the active metal center, altering the electron density around the metal site and influencing its adsorption and activation of N2 molecules; on the other hand, alloyed Al can serve as a secondary active site, forming weak adsorption sites for nitrogen species, promoting subsequent hydrogenation of nitrogen species and desorption of the product NH3. The mechanism of action is as follows: Figure 8 As shown.

[0053] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. The application of an aluminum-based alloy material in the photocatalytic synthesis of ammonia, characterized in that, The aluminum-based alloy material is composed of Al and metal M; the metal M is selected from one or more of Fe, Co, Ni, Mo, and Ru, and the mass fraction of metal M in the aluminum-based alloy material is 5-20%. The aluminum-based alloy material is prepared by the following method: S1. Using aluminum particles as a carrier, a metal M salt is modified on its surface to obtain a surface-modified aluminum-based material. S2. The aluminum-based material with surface modification in step S1 is subjected to heat treatment to obtain an aluminum-based alloy material; the heat treatment temperature is 300-550 ℃.

2. The application according to claim 1, characterized in that, In step S1, the metal M salt includes one or more of chloride salts, nitrate salts, sulfate salts, carbonate salts, acetylacetone salts, carbonyl salts, acetate salts, or other organic salts.

3. The application according to claim 1, characterized in that, In step S1, the method for surface modification with metal M salt includes any one of the following methods A and B: Method A: Mix aluminum particles with metallic M salt and grind or ball mill them; Method B: Disperse aluminum particles and metal M salt in a solvent, stir to react, and centrifuge.

4. The application according to claim 3, characterized in that, In method A, the time for mixing and grinding or ball milling is 5 to 300 minutes; And / or, in method B, the stirring reaction time is 0.5 to 24 h; the solvent is an aprotic solvent selected from one or more of toluene, hexane, cyclohexane, methylcyclohexane, 1,4-dioxane, tetrahydrofuran, and dichloromethane.

5. The application according to claim 1, characterized in that, In step S2, the heat treatment is carried out in a non-oxidizing atmosphere, which includes one or more of argon, nitrogen, and hydrogen; the heat treatment time is 0.5 to 24 hours.

6. The application according to claim 1, characterized in that, The application involves using aluminum-based alloy materials as catalysts in photocatalytic ammonia synthesis, comprising the following steps: loading the aluminum-based alloy material into a reactor, introducing reactant gas, and carrying out photocatalytic ammonia synthesis under light conditions.

7. The application according to claim 6, characterized in that, The amount of aluminum-based alloy material used in the photocatalytic ammonia synthesis reaction is 1~500 mg.

8. The application according to claim 6, characterized in that, The nitrogen source in the reactant gas is nitrogen, and the hydrogen source is hydrogen. The gas flow rate of the reactant gas is 1~100 mL / min. -1 The flow rate ratio of hydrogen to nitrogen is 0.1:1 to 10:

1.

9. The application according to claim 6, characterized in that, The pressure reaction conditions for the photocatalytic ammonia synthesis reaction are 0.1~1 MPa, temperature 320-360℃, and time 25-35 min.

10. The application according to claim 6, characterized in that, The light source in the illumination conditions includes one of a full-spectrum xenon lamp, an LED, or a high-intensity monochromatic laser; the illumination intensity is 1~50 W / cm². -2 .

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