A polyhedral strontium titanate composite light harvesting microbead, a preparation method and application thereof

Abstract

The application provides a kind of polyhedral strontium titanate composite light trapping microbeads and its preparation method and application, the polyhedral strontium titanate composite light trapping microbeads include modified porous hollow ceramic microbeads, and the surface of the modified porous hollow ceramic microbeads is adsorbed polyhedral strontium titanate catalyst.The application adsorbs polyhedral strontium titanate catalyst on the surface of modified porous hollow ceramic microbeads, and the obtained polyhedral strontium titanate composite light trapping microbeads can realize high photocarrier and photohole separation rate long time water splitting catalytic reaction under high intensity light irradiation, effectively improve the catalytic efficiency;And, avoid its application in the hydrogen production system of water splitting, reactor inner wall inlay catalyst is easy to fall off and equipment continuous stirring, operation is complex and maintenance difficult and other problems, has good development potential.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation, specifically relating to a polyhedral strontium titanate composite light-collecting microsphere, its preparation method, and its application. Background Technology

[0002] Traditionally, solar-powered water splitting for hydrogen production has primarily relied on catalysts directly exposed to sunlight. Currently, supported catalysts are mostly used for the degradation of recyclable organic wastewater, and are often halide perovskite materials such as bismuth iodide and cesium lead iodide. These materials are highly susceptible to decomposition and inactivation under high-intensity light, resulting in loss of catalytic efficiency and failing to meet the requirements of concentrated photocatalysis-hydrogen production systems. While common catalysts like titanium dioxide can be used under high-intensity light, supported titanium dioxide-based photocatalysts (such as those in CN201310232090.2 and CN201110168586.9) are formed by impregnating precursors with microspheres or cenospheres, followed by hydrothermal processes or direct calcination. However, the calcination process can lead to reactions between the precursor and the microsphere substrate, forming impurity phases and affecting catalytic efficiency. Therefore, the temperature and time control during the calcination process is crucial.

[0003] The concentrated photocatalytic hydrogen production system is a novel photocatalytic water splitting hydrogen production system. Existing patent CN202310517872.4 discloses a system that uses a number of reflectors to reflect full-spectrum sunlight onto a solar concentrator. The concentrator then focuses solar energy onto the catalyst surface for the photocatalytic water splitting reaction, thereby enhancing light intensity and catalytic efficiency. In this system, the catalyst consists of two parts: polyhedral strontium titanate embedded in the reactor inner wall and a certain concentration of polyhedral strontium titanate added as a raw material. To improve catalytic efficiency, the embedding process needs to be combined with organic matter. However, through reflection and concentration, full-spectrum sunlight is significantly enhanced. Under this significantly enhanced ultraviolet irradiation, the catalyst embedded in the reactor inner wall is prone to detachment. Furthermore, the photocatalytic water splitting hydrogen production reaction can only occur during the day; at night, due to the lack of sunlight, the photocatalytic reaction effectively stops. However, because strontium titanate has a much higher density than water, the stirring process in the reactor must be continuous 24 hours a day; otherwise, the catalyst will settle and agglomerate, reducing catalytic efficiency.

[0004] Therefore, how to improve the catalytic efficiency of strontium titanate catalysts while reducing the application difficulty is a technical challenge that needs to be addressed. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a polyhedral strontium titanate composite light-harvesting microsphere, its preparation method, and its applications. This invention adsorbs a polyhedral strontium titanate catalyst onto the surface of modified porous hollow ceramic microspheres. The resulting polyhedral strontium titanate composite light-harvesting microspheres can achieve long-term photocatalytic water splitting reactions with high photocharge and photohole separation rates under high-intensity light irradiation, effectively improving catalytic efficiency. Furthermore, it avoids the problems of easy catalyst detachment from the reactor inner wall, continuous equipment stirring, complex operation, and difficult maintenance encountered when applied to photocatalytic water splitting hydrogen production systems, demonstrating significant development potential.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a polyhedral strontium titanate composite light-collecting microsphere, the polyhedral strontium titanate composite light-collecting microsphere comprising modified porous hollow ceramic microspheres and a polyhedral strontium titanate catalyst adsorbed on the surface of the modified porous hollow ceramic microspheres.

[0008] This invention adsorbs a polyhedral strontium titanate catalyst onto the surface of modified porous hollow ceramic microspheres. The resulting polyhedral strontium titanate composite light-harvesting microspheres can achieve long-term photocatalytic water splitting reaction with high photocharge and photohole separation rates under high-intensity light irradiation, effectively improving catalytic efficiency. Furthermore, it avoids the problems of easy catalyst detachment from the reactor inner wall, continuous equipment stirring, complex operation, and difficult maintenance when applied to photocatalytic water splitting hydrogen production systems, and has good development potential.

[0009] As a preferred technical solution of the present invention, the modified porous hollow ceramic microspheres include a porous hollow ceramic substrate and an organic acid ester modifier attached to the surface of the porous hollow ceramic substrate.

[0010] Preferably, the organic ester modifier includes any one or a combination of at least two of glyceryl acetate, diethyl tartrate, gluconolactone, or ethyl acetate.

[0011] In this invention, the surface of the porous hollow ceramic substrate is modified with organic acid ester compounds. Under high temperature conditions, the organic acid esters react with the amino basic dispersant on the surface of the polyhedral strontium titanate catalyst, thereby achieving the purpose of fixing the catalyst on the surface of the microspheres.

[0012] Preferably, the porous hollow ceramic substrate comprises any one or a combination of at least two of silicon oxide, aluminum oxide, or zirconium oxide.

[0013] As a preferred embodiment of the present invention, the density of the modified porous hollow ceramic microspheres is 0.5-1 g / cm³. 3 For example, it could be 0.5 g / cm³. 3 0.6g / cm3 0.7g / cm 3 0.8 g / cm 3 0.9g / cm 3 or 1g / cm 3 wait.

[0014] Preferably, the particle size D50 of the modified porous hollow ceramic microspheres is 100-2000 μm, for example, it can be 100 μm, 300 μm, 500 μm, 700 μm, 900 μm, 1100 μm, 1300 μm, 1500 μm, 1700 μm or 1900 μm, and more preferably 500-1000 μm.

[0015] As a preferred technical solution of the present invention, the modified porous hollow ceramic microspheres have an average pore size of 5-50 μm, for example, 5 μm, 10 μm, 20 μm, 30 μm, 40 μm or 50 μm.

[0016] Preferably, the porosity of the modified porous hollow ceramic microspheres is 50-90%, for example, it can be 50%, 60%, 70%, 80% or 90%.

[0017] As a preferred embodiment of the present invention, the particle size D50 of the polyhedral strontium titanate catalyst is 0.1-1 μm, for example, it can be 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm or 1 μm, etc.

[0018] Preferably, the polyhedral strontium titanate catalyst includes an octadecahedral strontium titanate catalyst or a icosahedral strontium titanate catalyst.

[0019] Preferably, the polyhedral strontium titanate catalyst is supported on a co-catalyst.

[0020] In this invention, the polyhedral strontium titanate catalyst is supported as an auxiliary catalyst, which helps in the separation and transport of photogenerated charges and improves carrier mobility.

[0021] Preferably, the metal element in the co-catalyst includes any one or a combination of at least two of Rh, Co, or Cr.

[0022] Preferably, the mass ratio of the polyhedral strontium titanate catalyst to the modified porous hollow ceramic microspheres is 1:(50-200), for example, it can be 1:50, 1:100, 1:150 or 1:200, etc.

[0023] In this invention, if the mass ratio of the polyhedral strontium titanate catalyst to the modified porous hollow ceramic microspheres is too large, i.e., the amount of modified porous hollow ceramic microspheres is too small, the excess polyhedral strontium titanate catalyst will easily detach; if the mass ratio of the polyhedral strontium titanate catalyst to the modified porous hollow ceramic microspheres is too small, i.e., the amount of modified porous hollow ceramic microspheres is too large, the recombination rate will decrease, and the overall catalytic efficiency will decline.

[0024] In a second aspect, the present invention provides a method for preparing polyhedral strontium titanate composite light-collecting microspheres as described in the first aspect, the method comprising the following steps:

[0025] A suspension containing a polyhedral strontium titanate catalyst was mixed with modified porous hollow ceramic microspheres, subjected to heat treatment, and calcined to obtain the polyhedral strontium titanate composite light-collecting microspheres.

[0026] In this invention, the purpose of heat-treating the mixture obtained by mixing in the preparation method is to decompose the organic acid ester at high temperature and react with the amino basic dispersant, so that the polyhedral strontium titanate catalyst particles are anchored on the surface of porous hollow ceramic microspheres.

[0027] As a preferred embodiment of the present invention, the solid volume fraction of the suspension is 5-40%, for example, it can be 5%, 10%, 15%, 20%, 25%, 30%, 35% or 40%, etc.

[0028] Preferably, the mixing process is accompanied by stirring, the stirring speed is 50-200 rpm, for example, 50 rpm, 100 rpm, 150 rpm or 200 rpm, etc., and the time is 0.5-2h, for example, 0.5h, 1h, 1.5h or 2h.

[0029] Preferably, the heat treatment temperature is 50-80℃, for example, 50℃, 60℃, 70℃ or 80℃, and the time is 15-60min, for example, 15min, 20min, 30min, 40min, 50min or 60min.

[0030] Preferably, the heat treatment method includes water bath heating.

[0031] Preferably, after the heat treatment is completed, a settling and drying step is performed, followed by calcination.

[0032] Preferably, before the settling process, the heat-treated product is removed using a sieve with a mesh size of less than 100-200 μm, such as 90 μm, 80 μm, 70 μm, 60 μm or 50 μm.

[0033] It should be noted that the present invention does not limit the material of the mesh; for example, it may be metal or plastic.

[0034] Preferably, the settling time is 2-6 hours, for example, 2 hours, 3 hours, 4 hours, 5 hours or 6 hours.

[0035] Preferably, the drying temperature is 60-90℃, for example, 60℃, 70℃, 80℃ or 90℃, and the time is 12-24h, for example, 12h, 14h, 16h, 18h, 20h, 22h or 24h.

[0036] Preferably, the roasting temperature is 1000-1400℃, for example, 1000℃, 1100℃, 1200℃, 1300℃ or 1400℃, and the time is 1-3h, for example, 1h, 2h or 3h.

[0037] In this invention, if the calcination temperature is too low, the catalyst is prone to detachment; if the calcination temperature is too high, side reactions will occur, affecting the catalytic efficiency.

[0038] Preferably, the heating rate of the calcination is 5-15℃ / min, for example, it can be 5℃ / min, 7℃ / min, 9℃ / min, 11℃ / min, 13℃ / min or 15℃ / min, etc.

[0039] As a preferred embodiment of the present invention, the method for preparing the modified porous hollow ceramic microspheres includes the following steps:

[0040] The modified porous hollow oxide ceramic microspheres are obtained by blending porous hollow ceramic microspheres, hydrochloric acid and organic acid ester modifiers, and drying.

[0041] Preferably, the concentration of the hydrochloric acid is 1-3 mol / L, for example, it can be 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L or 3 mol / L, etc.

[0042] Preferably, the organic ester modifier includes any one or a combination of at least two of glyceryl acetate, diethyl tartrate, gluconolactone, or ethyl acetate.

[0043] Preferably, the blending process is accompanied by stirring, and the stirring rate is 50-200 rpm, for example, 50 rpm, 100 rpm, 150 rpm or 200 rpm.

[0044] Preferably, the mass ratio of the organic ester modifier to the porous hollow ceramic cenosphere is 1:(10-30) organic ester modifier, for example, it can be 1:10, 1:15, 1:20, 1:25 or 1:30, etc.

[0045] Preferably, the preparation steps of the suspension containing the polyhedral strontium titanate catalyst include:

[0046] Polyhedral strontium titanate particles and a dispersant are mixed in a solvent and the pH value is adjusted to obtain a suspension containing the polyhedral strontium titanate catalyst.

[0047] In this invention, the purpose of adjusting the pH value is to increase the surface charge of the polyhedral strontium titanate particles and improve the dispersion effect of the suspension.

[0048] It should be noted that the present invention does not limit the preparation method of polyhedral strontium titanate particles. For example, it may be a hydrothermal method or a molten salt method.

[0049] Preferably, the dispersant comprises tetramethylammonium hydroxide and / or tetraethylammonium hydroxide.

[0050] Preferably, the mass of the dispersant is 0.2-0.5% of the mass of the polyhedral strontium titanate particles, for example, it can be 0.2%, 0.3%, 0.4% or 0.5%, etc.

[0051] Preferably, the pH value of the suspension is 9-11, for example, it can be 9, 9.5, 10, 10.5 or 11.

[0052] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0053] (1) The porous hollow ceramic cenospheres were ultrasonically cleaned in deionized water for 1-12 hours, dried at 60-80℃, and then immersed in hydrochloric acid with a concentration of 1-3 mol / L. Then, an organic acid ester modifier was added and stirred at 50-200 rpm. Finally, the mixture was dried at 70-100℃ to obtain modified porous hollow oxide ceramic microspheres.

[0054] The mass ratio of organic ester modifier to porous hollow ceramic cenospheres is 1:(10-30);

[0055] (2) Disperse polyhedral strontium titanate particles in water, then add a dispersant and adjust the pH value to obtain a suspension containing polyhedral strontium titanate catalyst with a solid volume fraction of 5-40%.

[0056] The mass of the dispersant is 0.2-0.5% of the mass of the polyhedral strontium titanate particles, and the pH value of the suspension is 9-11.

[0057] (3) The modified porous hollow oxide ceramic microspheres and the suspension containing the polyhedral strontium titanate catalyst are mixed and stirred at a speed of 50-200 rpm for 0.5-2 h. Then, the mixture is heated in a water bath at a temperature of 50-80℃ for 15-60 min. After the mixture is heated, it is allowed to stand for 2-6 h and then dried for 12-24 h to obtain the product. The product is calcined at 1000-1400℃ for 1-3 h and then cooled to obtain polyhedral strontium titanate composite light-collecting microspheres.

[0058] The drying temperature is 60-90℃, and the calcination heating rate is 5-15℃ / min.

[0059] Thirdly, the present invention provides an application of the polyhedral strontium titanate composite light-collecting microspheres as described in the first aspect, wherein the polyhedral strontium titanate composite light-collecting microspheres are applied to a concentrated photocatalytic hydrogen production system.

[0060] It should be noted that the concentrated photocatalytic hydrogen production system uses a certain number of reflectors to reflect sunlight across the entire wavelength spectrum onto a solar concentrator. The concentrator then focuses the solar energy onto the catalyst surface for photocatalytic water splitting, thereby increasing light intensity and catalytic efficiency. In this system, the catalyst consists of two parts: polyhedral strontium titanate embedded in the inner wall of the reactor, and a certain concentration of polyhedral strontium titanate added as a raw material. To improve catalytic efficiency, the embedding process needs to be combined with organic matter. However, through reflection and concentration, sunlight across the entire wavelength spectrum is significantly enhanced. Under the significantly enhanced ultraviolet irradiation, the catalyst embedded in the inner wall of the reactor is prone to detachment. Furthermore, the photocatalytic water splitting hydrogen production reaction can only occur during the day; at night, due to the lack of sunlight, the photocatalytic reaction effectively stops. However, because strontium titanate has a much higher density than water, the stirring process in the reactor must be continuous 24 hours a day; otherwise, the catalyst will settle and agglomerate, reducing catalytic efficiency. Therefore, by replacing the polyhedral strontium titanate embedded in the reactor inner wall and the polyhedral strontium titanate added in the form of raw materials with polyhedral strontium titanate composite light-collecting microbeads in the present invention, the above-mentioned problems can be effectively avoided.

[0061] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0062] Compared with the prior art, the present invention has the following beneficial effects:

[0063] This invention adsorbs a polyhedral strontium titanate catalyst onto the surface of modified porous hollow ceramic microspheres. The resulting polyhedral strontium titanate composite light-harvesting microspheres can achieve long-term photocatalytic water splitting reaction with high photocharge and photohole separation rates under high-intensity light irradiation, effectively improving catalytic efficiency. Furthermore, it avoids the problems of easy catalyst detachment from the reactor inner wall, continuous equipment stirring, complex operation, and difficult maintenance when applied to photocatalytic water splitting hydrogen production systems, and has good development potential. Attached Figure Description

[0064] Figure 1 This is a SEM image of the modified porous hollow ceramic microspheres provided in Embodiment 1 of the present invention.

[0065] Figure 2 This is a SEM image of the polyhedral strontium titanate composite light-collecting microspheres prepared in Example 1 of the present invention.

[0066] Figure 3 This is a partial SEM magnification of the polyhedral strontium titanate composite light-collecting microspheres prepared in Example 1 of the present invention.

[0067] Figure 4 This is a SEM image of the polyhedral strontium titanate catalyst particles used in Example 1 of the present invention. Detailed Implementation

[0068] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0069] Example 1

[0070] This embodiment provides a polyhedral strontium titanate composite light-catching microsphere, which includes modified porous hollow ceramic microspheres and a polyhedral strontium titanate catalyst adsorbed on the surface of the modified porous hollow ceramic microspheres.

[0071] The modified porous hollow ceramic microspheres include a porous hollow ceramic substrate and an organic acid ester modifier attached to the surface of the porous hollow ceramic substrate. The porous hollow ceramic substrate is silicon oxide, and the organic acid ester modifier is glycerol acetate.

[0072] The modified porous hollow ceramic microspheres have a density of 0.7 g / cm³. 3 The particle size D50 is 1000 μm, the average pore size is 25 μm, and the porosity is 70%.

[0073] The polyhedral strontium titanate catalyst is an octahedral strontium titanate catalyst with a particle size D50 of 0.5 μm, and the mass ratio of the modified porous hollow ceramic microspheres to the polyhedral strontium titanate catalyst is 100:1.

[0074] This embodiment also provides a method for preparing the above-mentioned polyhedral strontium titanate composite light-harvesting microspheres, the preparation method comprising the following steps:

[0075] (1) The porous hollow ceramic cenospheres were ultrasonically cleaned in deionized water for 6 hours, dried at 70°C, and then immersed in hydrochloric acid with a concentration of 2 mol / L. Organic acid ester modifiers were added and stirred at 100 rpm. Finally, the mixture was dried at 85°C to obtain modified porous hollow oxide ceramic microspheres.

[0076] Among them, the porous hollow ceramic cenospheres are made of silicon dioxide, the organic acid ester modifier is glyceryl acetate, and the mass ratio of porous hollow ceramic cenospheres to organic acid ester modifier is 20:1.

[0077] (2) Disperse the polyhedral strontium titanate particles prepared by hydrothermal method in water, then add a dispersant and adjust the pH value to obtain a suspension containing polyhedral strontium titanate catalyst with a solid volume fraction of 20%.

[0078] The polyhedral strontium titanate particles are octahedral polyhedral strontium titanate, the dispersant is tetramethylammonium hydroxide, the mass of the dispersant is 0.35% of the mass of the polyhedral strontium titanate particles, and the pH value of the suspension is 10.

[0079] (3) The modified porous hollow oxide ceramic microspheres and the suspension containing the polyhedral strontium titanate catalyst were mixed and stirred at 100 rpm for 1 h. Then, the mixture was heated in a water bath at 65°C for 40 min. After heating, the mixture was removed using a metal mesh with a mesh size of 80 μm. The mixture was then allowed to stand for 4 h and dried for 18 h to obtain the product. The product was placed in an electric furnace at 1200°C for 2 h of calcination. After cooling in the furnace, polyhedral strontium titanate composite light-collecting microspheres were obtained.

[0080] The drying temperature was 75℃, and the calcination heating rate was 10℃ / min.

[0081] Example 2

[0082] This embodiment provides a polyhedral strontium titanate composite light-catching microsphere, which includes modified porous hollow ceramic microspheres and a polyhedral strontium titanate catalyst adsorbed on the surface of the modified porous hollow ceramic microspheres.

[0083] The modified porous hollow ceramic microspheres include a porous hollow ceramic substrate and an organic acid ester modifier attached to the surface of the porous hollow ceramic substrate. The porous hollow ceramic substrate is zirconium oxide, and the organic acid ester modifier is diethyl tartrate.

[0084] The modified porous hollow ceramic microspheres have a density of 0.5 g / cm³. 3 The particle size D50 is 500 μm, the average pore size is 50 μm, and the porosity is 50%.

[0085] The polyhedral strontium titanate catalyst is an octahedral strontium titanate catalyst with a particle size D50 of 0.2 μm, and the mass ratio of the modified porous hollow ceramic microspheres to the polyhedral strontium titanate catalyst is 200:1.

[0086] This embodiment also provides a method for preparing the above-mentioned polyhedral strontium titanate composite light-harvesting microspheres, the preparation method comprising the following steps:

[0087] (1) The porous hollow ceramic cenospheres were ultrasonically cleaned in deionized water for 3 hours, dried at 60°C, and then immersed in hydrochloric acid with a concentration of 1 mol / L. Organic acid ester modifiers were added and stirred at 50 rpm. Finally, the mixture was dried at 70°C to obtain modified porous hollow oxide ceramic microspheres.

[0088] Among them, the porous hollow ceramic cenospheres are zirconium oxide, the organic ester modifier is diethyl tartrate, and the mass ratio of porous hollow ceramic cenospheres to organic ester modifier is 10:1.

[0089] (2) Disperse the polyhedral strontium titanate particles prepared by hydrothermal method in water, then add a dispersant and adjust the pH value to obtain a suspension containing polyhedral strontium titanate catalyst with a solid volume fraction of 10%.

[0090] The polyhedral strontium titanate particles are octahedral polyhedral strontium titanate, the dispersant is tetraethylammonium hydroxide, the mass of the dispersant is 0.2% of the mass of the polyhedral strontium titanate particles, and the pH value of the suspension is 9.

[0091] (3) The modified porous hollow oxide ceramic microspheres and the suspension containing the polyhedral strontium titanate catalyst were mixed and stirred at 50 rpm for 2 h. Then, the mixture was heated in a water bath at 50 °C for 60 min. After heating, the mixture was removed using a metal mesh with a mesh size of 80 μm. The mixture was then allowed to stand for 2 h and dried for 12 h to obtain the product. The product was placed in an electric furnace at 1000 °C for 3 h of calcination. After cooling in the furnace, polyhedral strontium titanate composite light-collecting microspheres were obtained.

[0092] The drying temperature was 60℃, and the calcination heating rate was 5℃ / min.

[0093] Example 3

[0094] This embodiment provides a polyhedral strontium titanate composite light-catching microsphere, which includes modified porous hollow ceramic microspheres and a polyhedral strontium titanate catalyst adsorbed on the surface of the modified porous hollow ceramic microspheres.

[0095] The modified porous hollow ceramic microspheres include a porous hollow ceramic substrate and an organic acid ester modifier attached to the surface of the porous hollow ceramic substrate. The porous hollow ceramic substrate is alumina, and the organic acid ester modifier is gluconolactone.

[0096] The modified porous hollow ceramic microspheres have a density of 1 g / cm³. 3 The particle size D50 is 2000 μm, the average pore size is 10 μm, and the porosity is 90%.

[0097] The polyhedral strontium titanate catalyst is an octahedral strontium titanate catalyst with a particle size D50 of 1 μm, and the mass ratio of the modified porous hollow ceramic microspheres to the polyhedral strontium titanate catalyst is 50:1.

[0098] This embodiment also provides a method for preparing the above-mentioned polyhedral strontium titanate composite light-harvesting microspheres, the preparation method comprising the following steps:

[0099] (1) The porous hollow ceramic cenospheres were ultrasonically cleaned in deionized water for 12 hours, dried at 80°C, and then immersed in hydrochloric acid with a concentration of 3 mol / L. Organic acid ester modifiers were added and stirred at 200 rpm. Finally, the mixture was dried at 100°C to obtain modified porous hollow oxide ceramic microspheres.

[0100] Among them, the porous hollow ceramic cenospheres are made of alumina, the organic acid ester modifier is gluconolactone, and the mass ratio of porous hollow ceramic cenospheres to organic acid ester modifier is 30:1.

[0101] (2) Disperse the polyhedral strontium titanate particles prepared by hydrothermal method in water, then add a dispersant and adjust the pH value to obtain a suspension containing polyhedral strontium titanate catalyst with a solid volume fraction of 40%.

[0102] The polyhedral strontium titanate particles are octahedral polyhedral strontium titanate, the dispersant is tetramethylammonium hydroxide, the mass of the dispersant is 0.5% of the mass of the polyhedral strontium titanate particles, and the pH value of the suspension is 11.

[0103] (3) The modified porous hollow oxide ceramic microspheres and the suspension containing the polyhedral strontium titanate catalyst were mixed and stirred at 200 rpm for 0.5 h. Then, the mixture was heated in a water bath at 80 °C for 15 min. After heating, the mixture was removed using a metal mesh with a mesh size of 80 μm. The mixture was then allowed to stand for 6 h and dried for 24 h to obtain the product. The product was placed in an electric furnace at 1400 °C for 1 h of calcination. After cooling in the furnace, polyhedral strontium titanate composite light-collecting microspheres were obtained.

[0104] The drying temperature was 90℃, and the calcination heating rate was 15℃ / min.

[0105] Example 4

[0106] The difference between this embodiment and embodiment 1 is that the polyhedral strontium titanate particles used in step (2) are composite strontium titanate catalysts supported with Rh co-catalysts.

[0107] The remaining preparation methods and parameters are consistent with those in Example 1.

[0108] Example 5

[0109] The difference between this embodiment and Embodiment 1 is that the mass ratio of porous hollow ceramic beads and organic ester modifier in step (1) is adjusted to 5:1.

[0110] The remaining preparation methods and parameters are consistent with those in Example 1.

[0111] Example 6

[0112] The difference between this embodiment and Embodiment 1 is that the mass ratio of porous hollow ceramic beads and organic ester modifier in step (1) is adjusted to 35:1.

[0113] The remaining preparation methods and parameters are consistent with those in Example 1.

[0114] Example 7

[0115] The difference between this embodiment and Embodiment 1 is that the mass ratio of the modified porous hollow ceramic microspheres to the polyhedral strontium titanate catalyst is 45:1.

[0116] The remaining preparation methods and parameters are consistent with those in Example 1.

[0117] Example 8

[0118] The difference between this embodiment and Example 1 is that the mass ratio of the modified porous hollow ceramic microspheres to the polyhedral strontium titanate catalyst is 210:1.

[0119] The remaining preparation methods and parameters are consistent with those in Example 1.

[0120] Example 9

[0121] The difference between this embodiment and embodiment 1 is that the roasting temperature in step (3) is 900°C.

[0122] The remaining preparation methods and parameters are consistent with those in Example 1.

[0123] Example 10

[0124] The difference between this embodiment and embodiment 1 is that the roasting temperature in step (3) is 1500℃.

[0125] The remaining preparation methods and parameters are consistent with those in Example 1.

[0126] Figure 1 The image shows a SEM image of the modified porous hollow ceramic microspheres provided in Example 1. As can be seen from the image, the ceramic microspheres used in this invention have a porous hollow structure.

[0127] Figure 2 and Figure 3 SEM images and partial magnified SEM images of the polyhedral strontium titanate composite light-collecting microspheres prepared in Example 1 are shown respectively. As can be seen from the figures, the present invention successfully composites the polyhedral strontium titanate catalyst onto the surface of a porous hollow ceramic microsphere substrate.

[0128] Figure 4 The image shows an SEM image of the polyhedral strontium titanate catalyst particles used in Example 1. As can be seen from the image, the strontium titanate catalyst used in this invention has a polyhedral morphology.

[0129] Comparative Example 1

[0130] The difference between this comparative example and Example 1 is that step (1) is not performed, that is, the porous hollow ceramic float is not modified.

[0131] The remaining preparation methods and parameters are consistent with those in Example 1.

[0132] Comparative Example 2

[0133] This comparative example provides a polyhedral strontium titanate catalyst as described in Example 1.

[0134] Performance testing

[0135] The catalysts provided in the above embodiments and comparative examples are used in a concentrated photocatalytic hydrogen production system for photocatalytic water splitting to produce hydrogen. The specific process flow includes:

[0136] The raw materials for photocatalytic water splitting to produce hydrogen are added to the reaction vessel. Sunlight is reflected onto a solar concentrator using 500 mirrors, concentrating the sunlight and projecting it onto the reaction vessel for photocatalytic hydrolysis.

[0137] The hydrogen production rates of the above hydrogen production process are shown in Table 1.

[0138] Table 1

[0139]

[0140]

[0141] analyze:

[0142] As shown in the table above, this invention adsorbs a polyhedral strontium titanate catalyst onto the surface of modified porous hollow ceramic microspheres. The resulting polyhedral strontium titanate composite light-harvesting microspheres can achieve long-term photocatalytic water splitting reaction with high photocharge and photohole separation rates under high-intensity light irradiation, effectively improving catalytic efficiency. Furthermore, it avoids the problems of easy catalyst detachment from the reactor inner wall, continuous equipment stirring, complex operation, and difficult maintenance when applied to photocatalytic water splitting hydrogen production systems, demonstrating good development potential.

[0143] The data results from Examples 1 and 4 show that if the polyhedral strontium titanate particles are composite strontium titanate catalysts supported with Rh co-catalysts, they will help with the separation and transport of photogenerated charges, improve carrier mobility, and thus significantly improve hydrogen production efficiency.

[0144] The data from Examples 1 and 5-6 show that if the mass ratio of porous hollow ceramic cenospheres to organic acid ester modifiers is too small, the organic acid and dispersant will react too quickly, reducing the catalyst composite rate and thus significantly reducing the overall hydrogen production efficiency. If the mass ratio of porous hollow ceramic cenospheres to organic acid ester modifiers is too large, the catalyst will detach, thus significantly reducing the hydrogen production efficiency.

[0145] The data from Examples 1 and 7-8 show that if the mass ratio of the polyhedral strontium titanate catalyst to the modified porous hollow ceramic microspheres is too small, the recombination rate will decrease, leading to a decline in overall catalytic efficiency and a significant decrease in hydrogen production efficiency. If the mass ratio of the polyhedral strontium titanate catalyst to the modified porous hollow ceramic microspheres is too large, excess polyhedral strontium titanate catalyst will easily detach, resulting in a decrease in hydrogen production efficiency.

[0146] The data from Examples 1 and 9-10 show that if the calcination temperature is too low, the catalyst is prone to detachment, which reduces the hydrogen production efficiency; if the calcination temperature is too high, side reactions will occur, affecting the catalytic efficiency and causing a sharp drop in hydrogen production efficiency.

[0147] The data from Example 1 and Comparative Example 1 show that without modification of the porous hollow ceramic cenospheres, their catalytic efficiency is low, resulting in a hydrogen production efficiency as low as 1 mmol·g.-1 ·h -1 .

[0148] The data from Example 1 and Comparative Example 2 show that if only the polyhedral strontium titanate catalyst is used for photocatalytic water splitting to produce hydrogen, instead of adsorbing it onto the surface of modified porous hollow ceramic microspheres, the catalytic efficiency is low, resulting in a hydrogen production efficiency as low as 5 mmol·g. -1 ·h -1 .

[0149] The applicant declares that the present invention is illustrated by the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A polyhedral strontium titanate composite light-harvesting microsphere, characterized in that, The polyhedral strontium titanate composite light-harvesting microspheres include modified porous hollow ceramic microspheres and polyhedral strontium titanate catalysts adsorbed on the surface of the modified porous hollow ceramic microspheres. The modified porous hollow ceramic microspheres include a porous hollow ceramic substrate and an organic acid ester modifier attached to the surface of the porous hollow ceramic substrate; the mass ratio of the organic acid ester modifier to the porous hollow ceramic microspheres is 1:(10-30). The mass ratio of the polyhedral strontium titanate catalyst to the modified porous hollow ceramic microspheres is 1:(50-200); The polyhedral strontium titanate composite light-collecting microspheres are prepared at a calcination temperature of 1000-1400℃ for 1-3 hours. The organic acid ester modifier includes any one or a combination of at least two of glyceryl acetate, diethyl tartrate, gluconolactone, or ethyl acetate.

2. The polyhedral strontium titanate composite light-harvesting microspheres according to claim 1, characterized in that, The porous hollow ceramic substrate includes any one or a combination of at least two of silicon oxide, aluminum oxide, or zirconium oxide.

3. The polyhedral strontium titanate composite light-harvesting microspheres according to claim 1, characterized in that, The modified porous hollow ceramic microspheres have a density of 0.5-1 g / cm³. 3 .

4. The polyhedral strontium titanate composite light-harvesting microspheres according to claim 1, characterized in that, The modified porous hollow ceramic microspheres have a particle size D50 of 100-2000 μm.

5. The polyhedral strontium titanate composite light-harvesting microspheres according to claim 4, characterized in that, The modified porous hollow ceramic microspheres have a particle size D50 of 500-1000 μm.

6. The polyhedral strontium titanate composite light-harvesting microspheres according to claim 1, characterized in that, The modified porous hollow ceramic microspheres have an average pore size of 5-50 μm.

7. The polyhedral strontium titanate composite light-harvesting microspheres according to claim 1, characterized in that, The porosity of the modified porous hollow ceramic microspheres is 50-90%.

8. The polyhedral strontium titanate composite light-harvesting microspheres according to claim 1, characterized in that, The particle size D50 of the polyhedral strontium titanate catalyst is 0.1-1 μm.

9. The polyhedral strontium titanate composite light-harvesting microspheres according to claim 1, characterized in that, The polyhedral strontium titanate catalyst includes an octahedral strontium titanate catalyst or a ticosahedral strontium titanate catalyst.

10. The polyhedral strontium titanate composite light-harvesting microspheres according to claim 1, characterized in that, The polyhedral strontium titanate catalyst is supported as a catalyst.

11. The polyhedral strontium titanate composite light-harvesting microspheres according to claim 10, characterized in that, The metal element in the co-catalyst includes any one or a combination of at least two of Rh, Co, or Cr.

12. A method for preparing polyhedral strontium titanate composite light-harvesting microspheres as described in any one of claims 1-11, characterized in that, The preparation method includes the following steps: A suspension containing a polyhedral strontium titanate catalyst and modified porous hollow ceramic microspheres were mixed, heat-treated, and calcined to obtain the polyhedral strontium titanate composite light-collecting microspheres. The preparation method of the modified porous hollow ceramic microspheres includes the following steps: The modified porous hollow oxide ceramic microspheres were obtained by mixing porous hollow ceramic cenospheres, hydrochloric acid and organic acid ester modifiers and drying them. The mass ratio of the organic ester modifier to the porous hollow ceramic cenospheres is 1:(10-30); The calcination temperature is 1000-1400℃; The roasting time is 1-3 hours.

13. The preparation method according to claim 12, characterized in that, The solid volume fraction of the suspension is 5-40%.

14. The preparation method according to claim 12, characterized in that, The mixing process is accompanied by stirring, which is carried out at a speed of 50-200 rpm for a time of 0.5-2 hours.

15. The preparation method according to claim 12, characterized in that, The heat treatment is performed at a temperature of 50-80℃ for 15-60 minutes.

16. The preparation method according to claim 12, characterized in that, The heat treatment method includes water bath heating.

17. The preparation method according to claim 12, characterized in that, After the heat treatment is completed, a settling and drying process is performed, followed by calcination.

18. The preparation method according to claim 17, characterized in that, The settling time is 2-6 hours.

19. The preparation method according to claim 17, characterized in that, The drying temperature is 60-90℃, and the time is 12-24h.

20. The preparation method according to claim 17, characterized in that, The heating rate for roasting is 5-15℃ / min.

21. The preparation method according to claim 12, characterized in that, The concentration of the hydrochloric acid is 1-3 mol / L.

22. The preparation method according to claim 12, characterized in that, The organic acid ester modifier includes any one or a combination of at least two of glyceryl acetate, diethyl tartrate, gluconolactone, or ethyl acetate.

23. The preparation method according to claim 12, characterized in that, The blending process is accompanied by stirring at a speed of 50-200 rpm.

24. The preparation method according to claim 12, characterized in that, The preparation steps of the suspension containing the polyhedral strontium titanate catalyst include: Polyhedral strontium titanate particles and a dispersant are mixed in a solvent and the pH value is adjusted to obtain a suspension containing the polyhedral strontium titanate catalyst.

25. The preparation method according to claim 24, characterized in that, The dispersant includes tetramethylammonium hydroxide and / or tetraethylammonium hydroxide.

26. The preparation method according to claim 24, characterized in that, The mass of the dispersant is 0.2-0.5% of the mass of the polyhedral strontium titanate particles.

27. The preparation method according to claim 24, characterized in that, The pH value of the suspension is 9-11.

28. The preparation method according to claim 12, characterized in that, The preparation method includes the following steps: (1) The porous hollow ceramic microspheres were ultrasonically cleaned in deionized water for 1-12 hours, dried at 60-80℃, and then immersed in hydrochloric acid with a concentration of 1-3 mol / L. Then, an organic acid ester modifier was added and stirred at 50-200 rpm. Finally, the microspheres were dried at 70-100℃ to obtain modified porous hollow ceramic microspheres. The mass ratio of organic ester modifier to porous hollow ceramic cenospheres is 1:(10-30); (2) Disperse polyhedral strontium titanate particles in water, then add a dispersant and adjust the pH value to obtain a suspension containing polyhedral strontium titanate catalyst with a solid volume fraction of 5-40%. The mass of the dispersant is 0.2-0.5% of the mass of the polyhedral strontium titanate particles, and the pH value of the suspension is 9-11. (3) The modified porous hollow ceramic microspheres and the suspension containing the polyhedral strontium titanate catalyst are mixed and stirred at a speed of 50-200 rpm for 0.5-2 h. Then, the mixture is heated in a water bath at a temperature of 50-80℃ for 15-60 min. After the mixture is heated, it is allowed to stand for 2-6 h and then dried for 12-24 h to obtain the product. The product is calcined at 1000-1400℃ for 1-3 h and then cooled to obtain polyhedral strontium titanate composite light-collecting microspheres. The drying temperature is 60-90℃, and the calcination heating rate is 5-15℃ / min.

29. An application of the polyhedral strontium titanate composite light-harvesting microspheres as described in any one of claims 1-11, characterized in that, The polyhedral strontium titanate composite light-harvesting microspheres are used in a concentrated photocatalytic hydrogen production system.

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