High-entropy oxides for photo-thermal chemical looping and methods of making and using the same

Abstract

The application provides a high-entropy oxide for photo-thermal chemical chain and a preparation method and application thereof. a Ni b Mg c Cu d Zn e )Fe2O4, and the application adds an excessive amount of Zn element in the preparation process of the high-entropy oxide, and the addition of the Zn element promotes the increase of the specific surface area of the high-entropy oxide; the boiling point of the zinc element is 907 DEG C (1180 K), which means that the Zn element will obviously volatilize above 907 DEG C; by using the characteristic, the zinc makes the bulk density of the material larger in the volatilization process, and the specific surface area of the material is improved; the high-entropy oxide prepared by the application improves the specific surface area by 30 times, and further greatly improves the reaction performance.

Description

Technical Field

[0001] This invention belongs to the field of chemical chain hydrogen production technology, and particularly relates to a high-entropy oxide for photothermal chemical chaining, its preparation method and application. Background Technology

[0002] Chemical looping hydrogen production technology is a novel zero-carbon emission hydrogen production technology. If biomass-based fuels are used as feedstock, negative carbon emissions during the hydrogen production process can even be achieved. However, current chemical looping hydrogen production technologies generally face the following technical challenges: low lattice oxygen activity at low temperatures leads to low fuel conversion rates; and oxygen carriers are prone to sintering and deactivation at high temperatures. Although doping modification has improved oxygen activity and stability to some extent, high energy consumption and large equipment investment remain challenges for industrial application. Therefore, there is an urgent need to develop new chemical looping hydrogen production technologies operating under milder conditions.

[0003] In recent years, an increasing number of studies have incorporated solar energy into thermocatalytic systems (i.e., photothermal catalysis) in an attempt to address the technical challenges faced by traditional thermal conversion technologies. Currently, photothermal catalysis strategies have shown initial success in traditional thermochemical fields such as methane reforming for hydrogen production and Fischer-Tropsch synthesis. Compared to traditional thermochemical techniques, constructing photothermal catalytic systems helps improve product selectivity, activate intermediates, and lower the overall reaction energy barrier. Furthermore, the photothermal effect can provide sufficient heat energy for thermodynamically unfavorable reactions, thus mitigating the need for stringent reaction conditions (such as high temperature and high pressure). Chemical chaining for hydrogen production falls under the category of thermal conversion technologies, and coupling photocatalysis is an effective means to solve the technical challenges of chemical chaining for hydrogen production. However, to date, there are few reports of applying photothermal catalysis to chemical chaining for hydrogen production.

[0004] Applying photothermal catalysis to chemical looping hydrogen production technology requires oxygen carriers with good photothermal responsiveness and photocatalytic performance. Therefore, developing oxygen carriers with both photoresponsiveness and photocatalytic performance for use in the field of photothermal chemical looping is of great significance. Summary of the Invention

[0005] In view of this, the present invention proposes a high-entropy oxide for photothermal chemical chaining, its preparation method and application, in order to solve the technical problems existing in the prior art.

[0006] In a first aspect, the present invention provides a high-entropy oxide for photothermal chemical chaining, the chemical formula of which is (Co a Ni b Mg c Cu d Zn e )Fe2O4, where a:b:c:d:e is (0.1~0.25):(0.1~0.25):(0.1~0.25):(0.1~0.25):(0.1~0.25).

[0007] Preferably, the high-entropy oxide used for photothermal chemical chaining has the chemical formula (Co). 0.2 Ni 0.2 Mg 0.2 Cu 0.2 Zn 0.2 )Fe2O4.

[0008] Secondly, the present invention also provides a method for preparing the high-entropy oxide for photothermal chemical chaining, comprising the following steps:

[0009] Co, Ni, Mg, Cu, Zn, and Fe sources were mixed with citric acid, then water was added and stirred to obtain a gel.

[0010] After drying the gel, it is calcined to obtain a high-entropy oxide for photothermal chemical chaining.

[0011] Preferably, the method for preparing the high-entropy oxide for photothermal chemical chaining involves a calcination temperature of 907–1100°C and a calcination time of 8–12 h.

[0012] Preferably, the method for preparing the high-entropy oxide for photothermal chemical chaining involves mixing Co source, Ni source, Mg source, Cu source, Zn source, Fe source with citric acid, then adding water, and stirring at 90-100°C to obtain a gel.

[0013] The gel was dried at 100–110°C and then calcined.

[0014] Preferably, in the method for preparing the high-entropy oxide for photothermal chemical chaining, the Co source includes at least one of cobalt nitrate, cobalt sulfate, and cobalt chloride;

[0015] The Ni source includes at least one of nickel nitrate, nickel sulfate, and nickel chloride;

[0016] The Mg source includes at least one of magnesium nitrate, magnesium sulfate, and magnesium chloride;

[0017] The Cu source includes at least one of copper nitrate, copper sulfate, and copper chloride;

[0018] The Zn source includes at least one of zinc nitrate, zinc sulfate, and zinc chloride;

[0019] The Fe source includes at least one of ferric nitrate, ferric sulfate, and ferric chloride.

[0020] Preferably, in the method for preparing the high-entropy oxide for photothermal chemical chaining, the molar ratio of Co in the Co source, Ni in the Ni source, Mg in the Mg source, Cu in the Cu source, Zn in the Zn source, and citric acid is (0.1~0.25):(0.1~0.25):(0.1~0.25):(0.1~0.25):(0.5~2).

[0021] Thirdly, the present invention also provides an application of the high-entropy oxide for photothermal chemical chaining described above or the high-entropy oxide for photothermal chemical chaining prepared by the preparation method described above in the photothermal chemical chaining reforming to prepare syngas and hydrogen.

[0022] Preferably, in the aforementioned application, a high-entropy oxide from a photothermal chemical chain is placed in a fuel reactor, a light source and an electric furnace are turned on to heat the fuel reactor, and after reaching the target temperature, fuel is introduced into the fuel reactor, and after reaction, syngas is obtained.

[0023] The high-entropy oxides from the photothermal chemical chain generated by the reaction in the fuel reactor are placed in a steam reactor. A light source and an electric furnace are turned on to heat the fuel reactor. Once the target temperature is reached, water vapor is introduced into the steam reactor, and after the reaction, H2 is obtained.

[0024] Preferably, in the application described, the fuel comprises toluene and / or water vapor;

[0025] In the step of turning on the light source and electric furnace to heat the fuel reactor to the target temperature, the current of the light source is controlled to be 14-20A and the target temperature is 500-600℃.

[0026] The fuel flow rate is 0.01–0.1 mL / min;

[0027] The high-entropy oxides of the photothermal chemical chain are placed in a fuel reactor, and the mass of the high-entropy oxides of the photothermal chemical chain is 1-2g.

[0028] The high-entropy oxide for photothermal chemical chaining, its preparation method, and its application, as described in this invention, have the following advantages over existing technologies:

[0029] 1. The chemical formula of the high-entropy oxide used in the photothermal chemical chaining of the present invention is (Co a Ni b Mg c Cu d Zn eIn the preparation of high-entropy oxides, an excess of Zn element was added to Fe2O4. The addition of Zn element promoted the increase of the specific surface area of ​​the high-entropy oxides. The boiling point of zinc element is 907℃ (1180K), which means that Zn element will undergo significant volatilization above 907℃. Taking advantage of this characteristic, the material bulkiness is increased during the volatilization process, thereby increasing the specific surface area of ​​the material. The high-entropy oxides prepared by this invention increase the specific surface area by 30 times, thereby greatly improving their reactivity.

[0030] 2. Compared with ordinary CoFe2O4 spinel oxide, the high-entropy oxide of the present invention exhibits significantly improved hydrogen production performance. At 550°C, the hydrogen yield of the high-entropy oxide is 24.17 mmol / g OC, which is much higher than the 5.24 mmol / g OC of ordinary CoFe2O4 oxygen carrier. The syngas yield prepared by the high-entropy oxide of the present invention reaches 19.64 mmol / g OC and the toluene conversion rate is 93.32%, while the syngas yield of ordinary CoFe2O4 spinel oxide is about 3.21 mmol / g OC and the toluene conversion rate is 45.91%. Compared with ordinary CoFe2O4 spinel oxide, the high-entropy oxide of the present invention significantly improves the toluene conversion performance. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a SEM image of the high-entropy oxide (HEO) for photothermal chemical chaining prepared in Example 1 of the present invention;

[0033] Figure 2 The image shows a SEM image of the oxide CoFe2O4 prepared in Comparative Example 1.

[0034] Figure 3 The results of BET surface area measurements are as follows: for the high entropy oxide (HEO) in Example 1 and for the oxide CoFe2O4 in Comparative Example 1.

[0035] Figure 4 The thermal response capabilities of the high-entropy oxide (HEO) in Example 1 and the oxide CoFe2O4 in Comparative Example 1;

[0036] Figure 5 The light absorption properties of the high-entropy oxide (HEO) in Example 1 and the oxide CoFe2O4 in Comparative Example 1 are shown.

[0037] Figure 6 This is a diagram of the experimental apparatus for the present invention;

[0038] Figure 7 The hydrogen yields of the high-entropy oxide (HEO) in Example 1 and the oxide CoFe2O4 in Comparative Example 1 are given.

[0039] Figure 8 The syngas yield and toluene conversion rate are for the high-entropy oxide (HEO) in Example 1 and the oxide CoFe2O4 in Comparative Example 1. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0041] To better understand the invention and not to limit its scope, all figures indicating amounts, percentages, and other numerical values ​​used in this application should, in all cases, be understood to be modified by the word "approximately." Therefore, unless specifically stated otherwise, the numerical parameters listed in the specification and appended claims are approximate values ​​and may vary depending on the desired properties being sought. Each numerical parameter should at least be considered as obtained based on reported significant figures and through conventional rounding methods.

[0042] It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of embodiments. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single digits within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0043] This invention provides a high-entropy oxide for photothermal chemical chaining, with the chemical formula (Co).a Ni b Mg c Cu d Zn e )Fe2O4, where a:b:c:d:e is (0.1~0.25):(0.1~0.25):(0.1~0.25):(0.1~0.25):(0.1~0.25).

[0044] The high-entropy oxide of the present invention for photothermal chemical chaining has the chemical formula (Co). a Ni b Mg c Cu d Zn e Fe₂O₄, a high-entropy oxide, is prepared by adding an excess of Zn, which promotes an increase in the specific surface area of ​​the high-entropy oxide. The high-entropy oxide of this invention possesses both good photoresponsiveness and photocatalytic performance, and can be used for photothermal chemical looping hydrogen production.

[0045] In some embodiments, the chemical formula of the high-entropy oxide is (Co 0.2 Ni 0.2 Mg 0.2 Cu 0.2 Zn 0.2 )Fe2O4.

[0046] Based on the same inventive concept, the present invention also provides a method for preparing the above-mentioned high-entropy oxide for photothermal chemical chaining, comprising the following steps:

[0047] S1. Mix Co source, Ni source, Mg source, Cu source, Zn source, Fe source with citric acid, then add water and stir to obtain a gel;

[0048] S2. After drying the gel, calcination is performed to obtain a high-entropy oxide for photothermal chemical chaining.

[0049] In some embodiments, the calcination temperature is 907–1100°C and the calcination time is 8–12 h.

[0050] The low specific surface area has always been a problem in the preparation of high-entropy oxides. High-temperature preparation methods (such as calcination at 1000℃ for 10 hours) result in a small specific surface area, which is detrimental to the reaction. However, the high-entropy oxide preparation method of this invention involves the excessive addition of Zn during the preparation process. The addition of Zn promotes the increase of the specific surface area of ​​the high-entropy oxide. Zinc has a boiling point of 907℃ (1180K), meaning that Zn will undergo significant volatilization above 907℃. Utilizing this characteristic, the volatilization of zinc increases the bulkiness of the material, thereby increasing the specific surface area. The high-entropy oxide prepared by this invention increases the specific surface area by 30 times, thus greatly improving its reactivity.

[0051] In some embodiments, Co source, Ni source, Mg source, Cu source, Zn source, Fe source are mixed with citric acid, then water is added, and the mixture is stirred at 90-100°C to obtain a gel.

[0052] The gel was dried at 100–110°C and then calcined.

[0053] In some embodiments, the Co source includes at least one of cobalt nitrate, cobalt sulfate, and cobalt chloride.

[0054] In some embodiments, the Ni source includes at least one of nickel nitrate, nickel sulfate, and nickel chloride.

[0055] In some embodiments, the Mg source includes at least one of magnesium nitrate, magnesium sulfate, and magnesium chloride.

[0056] In some embodiments, the Cu source includes at least one of copper nitrate, copper sulfate, and copper chloride.

[0057] In some embodiments, the Zn source includes at least one of zinc nitrate, zinc sulfate, and zinc chloride.

[0058] In some embodiments, the Fe source includes at least one of ferric nitrate, ferric sulfate, and ferric chloride.

[0059] In some embodiments, the molar ratio of Co in the Co source, Ni in the Ni source, Mg in the Mg source, Cu in the Cu source, Zn in the Zn source, and citric acid is (0.1–0.25):(0.1–0.25):(0.1–0.25):(0.1–0.25):(0.5–2).

[0060] In some embodiments, the molar ratio of citric acid to water is (0.5–2):(50–60).

[0061] Based on the same inventive concept, the present invention also provides the application of the above-mentioned high-entropy oxide for photothermal chemical chaining or the high-entropy oxide for photothermal chemical chaining prepared by the above-mentioned preparation method in the photothermal chemical chaining reforming to produce syngas and hydrogen.

[0062] In some embodiments, the above-described application involves placing high-entropy oxides from photothermal chemical chains into a fuel reactor, turning on a light source and an electric furnace to heat the fuel reactor, and after reaching the target temperature, introducing fuel into the fuel reactor, and obtaining syngas through a reaction.

[0063] The high-entropy oxides from the photothermal chemical chain generated by the reaction in the fuel reactor are placed in a steam reactor. A light source and an electric furnace are turned on to heat the fuel reactor. Once the target temperature is reached, water vapor is introduced into the steam reactor, and after the reaction, H2 is obtained.

[0064] In some of the above applications, the fuel includes toluene and / or water vapor;

[0065] In the step of turning on the light source and electric furnace to heat the fuel reactor to reach the target temperature, the current of the light source is controlled to be 14-20A and the target temperature is 500-600℃.

[0066] The fuel flow rate is 0.01–0.1 mL / min;

[0067] The high-entropy oxides of the photothermal chemical chain are placed in a fuel reactor, and the mass of the high-entropy oxides of the photothermal chemical chain is 1-2g.

[0068] Preferably, the current of the light source is controlled at 20A and the target temperature is 550℃.

[0069] Specifically, in the fuel reactor, fuel (e.g., toluene) undergoes a reforming reaction with high-entropy oxides under light irradiation to produce syngas. Depending on the specific circumstances, some water vapor may need to be introduced. During the syngas production process, the lattice oxygen of the high-entropy oxides is reduced to generate a reduced oxygen carrier. The reduced oxygen carrier is then placed in a steam reactor, where it reacts with water vapor to produce high-concentration hydrogen. Simultaneously, the reduced oxygen carrier is oxidized and regenerated to obtain the original high-entropy oxides. In the photothermal chemical chain, light enters the fuel reactor and steam reactor through a glass window, which has an effect on both the reforming reaction and the water vapor oxidation reaction.

[0070] In some embodiments, the above-described application involves placing an appropriate amount (e.g., 1-2 g) of Co-Fe-based photothermal oxygen carrier in a fuel reactor. The light source and electric furnace are turned on, and the fuel reactor is heated to a preset reaction temperature. After the temperature stabilizes, nitrogen gas is introduced to purge the reactor for 5 minutes. Subsequently, toluene and water are introduced at a flow rate of 0.025 ml / min for 10 minutes. After the reaction is complete, the toluene is turned off, and water vapor is continued to be introduced until the hydrogen concentration drops below 0.5%, at which point the experiment is stopped. An online gas analyzer is used to measure the gas concentration and calculate the data.

[0071] The following specific embodiments further illustrate the high-entropy oxide for photothermal chemical chaining, its preparation method, and its application. This section further illustrates the content of the present invention with reference to specific embodiments, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the art.

[0072] Example 1

[0073] This application provides a method for preparing a high-entropy oxide for photothermal chemical chaining, comprising the following steps:

[0074] S1. Mix Co(NO3)2·6H2O, Ni(NO3)2·6H2O, Mg(NO3)2·6H2O, Cu(NO3)2, Zn(NO3)2·6H2O, Fe(NO3)2·9H2O with citric acid, then add water and stir at 95°C to obtain a gel.

[0075] S2. Place the gel in a drying oven at 105°C until the sample is completely dry;

[0076] S3. Place the dried sample in a muffle furnace and calcine it at 1000℃ for 10h. After cooling, grind and sieve it to a size range of less than 212μm (70 mesh) to obtain the high entropy oxide (denoted as HEO) for photothermal chemical chaining.

[0077] The molar ratio of Co(NO3)2·6H2O, Ni(NO3)2·6H2O, Mg(NO3)2·6H2O, Cu(NO3)2, Zn(NO3)2·6H2O, Fe(NO3)2·9H2O, and citric acid is 0.2:0.2:0.2:0.2:0.4:2:1. Zn(NO3)2·6H2O is added in excess compared to the other metal salt precursors.

[0078] The molar ratio of citric acid to water is 1:55.

[0079] Comparative Example 1

[0080] This comparative example provides a method for preparing the oxide CoFe2O4, including the following steps:

[0081] S1. Mix Co(NO3)2·6H2O, Fe(NO3)2·9H2O with citric acid, then add water and stir at 95℃ to obtain a gel;

[0082] S2. Place the gel in a drying oven at 105°C until the sample is completely dry;

[0083] S3. Place the dried sample in a muffle furnace and calcine at 1000℃ for 10h. After cooling, grind and sieve to a size range of less than 212μm (70 mesh) to obtain the oxide CoFe2O4.

[0084] The molar ratio of Co(NO3)2·6H2O, Fe(NO3)2·9H2O, and citric acid is 1:2:1.

[0085] The molar ratio of citric acid to water is 1:55.

[0086] Example 2

[0087] This application provides the application of the high-entropy oxide prepared in Example 1 for photothermal chemical chaining in the production of hydrogen and syngas through photothermal chemical chaining, specifically including:

[0088] Performance testing

[0089] Figure 2 SEM image of the high-entropy oxide (HEO) for photothermal chemical chaining prepared in Example 1; Figure 3 The image shows a SEM image of the oxide CoFe2O4 prepared in Comparative Example 1.

[0090] from Figure 1 As can be seen, the surface of the high entropy oxide (HEO) prepared by this invention has particles of different sizes and well-developed pores; while the surface of the oxide CoFe2O4 consists of particles of the same size.

[0091] Figure 3 The results show the BET surface area measurements of the high-entropy oxide (HEO) and the oxide CoFe2O4 in Example 1. From... Figure 3 As can be seen from the data, the BET surface area of ​​the high-entropy oxide (HEO) in Example 1 is 29.8672 m². 2 / g, the BET surface area of ​​the oxide CoFe2O4 in Comparative Example 1 is 0.9573m². 2 / g.

[0092] Figure 4The results show the thermal response of the high-entropy oxide (HEO) and the oxide CoFe2O4 in Example 1. The thermal response test was conducted using an infrared thermal imager. For each test, 0.1g of sample was laid out and compacted, and the temperature change of the sample under illumination was recorded. The sample spot area was 2.0096cm². 2 The power density is 0.1 W / cm³. 2 .from Figure 4 As can be seen, under illumination, the heating rate of the high-entropy oxide oxygen support is significantly higher than that of the ordinary CoFe2O4 oxygen support. After one minute of illumination, the high-entropy oxide oxygen support heated 95.1 degrees Celsius, while the ordinary CoFe2O4 oxygen support heated 64.7 degrees Celsius, indicating an enhanced photothermal effect.

[0093] Figure 5 The photoresponse properties of the high-entropy oxide (HEO) in Example 1 and the oxide CoFe2O4 in Comparative Example 1 are shown. UV-Vis-NIR diffuse reflectance measurements were performed on a UV-Vis-NIR spectrophotometer (UV-3600i Plus, Shimadzu). Baseline scans were performed using a barium sulfate standard white plate, and the spectra of the samples were acquired after calibration. Figure 5 As can be seen, in the near-infrared region, especially in the wavelength range greater than 1800 nm, the photoresponse performance of high-entropy oxide (HEO) is significantly improved compared to that of CoFe2O4 oxygen carrier. In the range of 10–60 s, the temperature of high-entropy oxide (HEO) rises from 52 °C to 95 °C, while the temperature of CoFe2O4 oxygen carrier rises from 34 °C to 62 °C. This indicates that high-entropy oxide (HEO) can utilize light with lower energy, which is conducive to the occurrence of photothermal reactions.

[0094] Figure 6 This is a schematic diagram of the experimental setup for the high-entropy oxide (HEO) in a fixed-bed experiment in Example 3. The entire setup consists of a feeding unit, a carrier gas unit, a reaction unit, and a product collection unit. The feeding unit consists of two fully automatic injection pumps (…). Figure 6 The system consists of an injection pump and two pumps, each responsible for carrying out water ( Figure 6 (H2O) and toluene ( Figure 6 The feeding operation of Toluene (in the middle). The carrier gas unit mainly consists of gas cylinders ( Figure 6 The reaction unit consists of a xenon lamp light source system, a vertical tube furnace, and a quartz tube. During the reaction, nitrogen (Ar, 99.99 vol%) is continuously introduced into the quartz tube at a flow rate of 100 ml / min as a purge gas, and the reaction occurs within the quartz tube. The tube furnace is electrically heated and insulated, and equipped with a thermocouple (N2 and Air). Figure 6 A K-type thermocouple is inserted to detect the temperature inside the furnace. Before the reaction begins, a small amount of quartz wool is placed... Figure 6A high-entropy oxide (1.3g) was placed on the quartz wool at the lower end of a quartz tube. The tube furnace was heated from room temperature to 550℃ at a rate of 20℃ / min under an argon atmosphere, while the xenon lamp was turned on. Figure 6 The high-entropy oxides are irradiated by a xenon lamp (light source) with the lamp current controlled at 20A. After the temperature stabilizes, the reaction proceeds to the fuel reactor (FR) stage. Toluene and water are simultaneously introduced via two separate syringe pumps at a flow rate of 0.025 ml / min. The high-entropy oxides are reduced, and syngas (a mixture of CO and H2) is generated. After 10 minutes of this process, the syringe pump valves are closed, ending the feed into the fuel reactor. Once the concentrations of all gases have decreased to below 0.5%, the reaction switches to the steam reaction (SR) stage. Deionized water is introduced via a syringe pump at a flow rate of 0.1 ml / min, rapidly evaporating within the reactor and reacting with the reduced high-entropy oxides to quickly generate a large amount of hydrogen, completing the oxidation and regeneration of the high-entropy oxides. Throughout the reaction, the reaction temperature is maintained at a constant 550°C, and the xenon lamp current is controlled at 20A. The gaseous products generated by the reaction are passed sequentially through a condenser and a desiccant, and then introduced into an online mass spectrometer (HPR-20R&D, Engelhead Analytical Technology Ltd.) for continuous online analysis and recording of gas concentrations (including CO, CO2, CH4 and H2).

[0095] use Figure 6 The apparatus described above, using the high-entropy oxide (HEO) from Example 1 and the oxide CoFe2O4 from Comparative Example 1 (using CoFe2O4 instead of HEO for the experiment), prepares hydrogen gas, and the hydrogen yield is calculated as follows: Figure 7 As shown.

[0096] Figure 7 The hydrogen yields are those of the high-entropy oxide (HEO) in Example 1 and the oxide CoFe2O4 in Comparative Example 1.

[0097] H2 represents the hydrogen yield (Y). H2 ,mmol / g OC).

[0098] Specifically, hydrogen yield (Y) H2 The calculation method for mmol / g OC is as follows:

[0099]

[0100] in, It is the amount of H2 produced, m OC It refers to the quality of the oxygen carrier used.

[0101] from Figure 7It can be seen that the hydrogen production performance of high-entropy oxides is significantly improved compared to ordinary CoFe2O4 spinel-type oxides. At 550℃, the hydrogen yield of high-entropy oxides is 24.17 mmol / g OC, which is much greater than that of ordinary CoFe2O4 oxygen carriers (5.24 mmol / g OC).

[0102] use Figure 6 The apparatus described above, using the high-entropy oxide (HEO) from Example 1 and the oxide CoFe2O4 from Comparative Example 1 (using CoFe2O4 instead of HEO for the experiment), prepared syngas. The fuel (toluene) conversion rate and syngas yield were calculated, and the results are as follows: Figure 8 As shown.

[0103] Figure 8 The figure represents the fuel (toluene) conversion rate of the high-entropy oxide (HEO) in Example 1 and the oxide CoFe2O4 in Comparative Example 1. Figure 8 Fuel Conversion in this context refers to the toluene conversion rate.

[0104] Toluene conversion rate The calculation method is as follows:

[0105]

[0106] Where, n CO This represents the amount of CO produced. The amount of substance representing CO2. n represents the amount of CH4. C-Toluene This represents the amount of toluene used.

[0107] Y syngas The syngas yield (Y) represents the syngas production rate. syngas The specific calculation method is as follows: (ml / g OC)

[0108]

[0109] Among them, V CO The volume of CO produced. The volume produced by H2 is V. total It is the total volume of gas produced, m OC It refers to the quality of the oxygen carrier used.

[0110] from Figure 8 As can be seen, the syngas yield prepared using the high-entropy oxide in Example 1 reached 19.64 mmol / g OC, and the toluene conversion rate was 93.32%, while the syngas yield of ordinary CoFe2O4 spinel-type oxide was approximately 3.21 mmol / g OC, and the toluene conversion rate was 45.91%. Figure 8 It can be seen that the high-entropy oxides significantly improve the conversion performance of toluene compared to ordinary CoFe2O4 spinel-type oxides. CoFe2O4 prepared by the sol-gel method showed weak conversion ability for toluene, with 54.09% of the toluene remaining unconverted and unutilized. In contrast, the high-entropy oxides prepared by the same method exhibited strong conversion ability for toluene, with 93.92% of the toluene being converted.

[0111] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. The application of a high-entropy oxide for photothermal chemical chaining in the photothermal chemical chaining reforming process for the preparation of syngas and hydrogen; High-entropy oxides from photothermal chemical chains are placed in a fuel reactor. A light source and an electric furnace are turned on to heat the fuel reactor. Once the target temperature is reached, fuel is introduced into the fuel reactor. After the reaction, syngas is obtained. The high-entropy oxides that have undergone photothermal chemical chain reaction in the fuel reactor are placed in a steam reactor. The fuel reactor is heated by a light source and an electric furnace. After reaching the target temperature, water vapor is introduced into the steam reactor. After the reaction, H2 is obtained. The fuel is toluene; In the step of turning on the light source and electric furnace to heat the fuel reactor to reach the target temperature, the current of the light source is controlled to be 14~20A and the target temperature is 550℃. The chemical formula of the high-entropy oxide used in photothermal chemical chains is (Co 0.2 Ni 0.2 Mg 0.2 Cu 0.2 Zn 0.2 Fe2O4, its preparation method includes the following steps: Co, Ni, Mg, Cu, Zn, and Fe sources were mixed with citric acid, then water was added and stirred to obtain a gel. After drying the gel, calcination yields a high-entropy oxide suitable for photothermal chemical chains. The calcination temperature was 1000℃ and the calcination time was 10h. The Co source includes at least one of cobalt nitrate, cobalt sulfate, and cobalt chloride; The Ni source includes at least one of nickel nitrate, nickel sulfate, and nickel chloride; The Mg source includes at least one of magnesium nitrate, magnesium sulfate, and magnesium chloride; The Cu source includes at least one of copper nitrate, copper sulfate, and copper chloride; The Zn source includes at least one of zinc nitrate, zinc sulfate, and zinc chloride; The Fe source includes at least one of ferric nitrate, ferric sulfate, and ferric chloride; The molar ratio of Co in the Co source, Ni in the Ni source, Mg in the Mg source, Cu in the Cu source, Zn in the Zn source, Fe source, and citric acid is 0.2:0.2:0.2:0.2:0.4:2:

1.

2. The application as described in claim 1, characterized in that, The fuel flow rate is 0.01~0.1 mL / min; The high-entropy oxides of the photothermal chemical chain are placed in a fuel reactor, and the mass of the high-entropy oxides of the photothermal chemical chain is 1~2g.

3. The application as described in claim 1, characterized in that, Co, Ni, Mg, Cu, Zn, and Fe sources were mixed with citric acid, and then water was added. The mixture was stirred at 90-100°C to obtain a gel. The gel was dried at 100~110℃ and then calcined.

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