Pt1 / Co3O4 / GCN catalyst for photo-thermal synergistic catalytic oxidation of VOCs in catering industry and preparation method of Pt1 / Co3O4 / GCN catalyst

Abstract

The invention discloses a Pt1 / Co3O4 / GCN catalyst for photo-thermal synergistic catalytic oxidation of VOCs in catering industry and a preparation method thereof, and belongs to the technical field of environmental catalytic materials. The catalyst is Pt1 / Co3O4 / GCN of which a Pt single atom is anchored to Co3O4 / graphite phase carbon nitride. A Co3O4 nano block is derived through a Prussian blue analogue self-sacrifice template method, after electrostatic self-assembly with GCN is conducted, Pt monatomic is loaded through an in-situ ice crystal auxiliary photo-reduction method, and the Co3O4 / GCN composite material is prepared. According to the catalyst, high-efficiency degradation of typical catering oil fume long-chain alkane VOCs such as heptane and octane is realized. The preparation process of the catalyst is green, and the catalyst shows excellent low-temperature catalytic activity (T90% = 195 DEG C), stability and water resistance to high-concentration heptane (3000 ppm) under simulated sunlight.

Description

Technical Field

[0001] This invention belongs to the fields of catalytic chemistry and environmental chemistry, specifically relating to a Pt1 / Co3O4 / GCN catalyst for photothermal synergistic catalytic oxidation of VOCs in the catering industry and its preparation method. Background Technology

[0002] Restaurant fumes have become a significant source of urban air pollution. These fumes primarily consist of particulate matter, water vapor, and VOCs. The VOCs are complex, encompassing alkanes with five or more carbon atoms (such as heptane and octane), aromatic hydrocarbons (such as benzene and toluene), and oxygen-containing VOCs (such as acrolein, hexanal, and pentanal). These substances are highly irritating and carcinogenic, posing serious health risks.

[0003] Currently used oil fume treatment technologies, such as electrostatic deposition and mechanical filtration, can effectively remove particulate matter from oil fumes, but their purification effect on VOCs is unsatisfactory. Thermocatalytic oxidation technology, as the mainstream technology for VOCs treatment, still suffers from reliance on fossil fuels and high energy consumption. While photocatalysis technology has significant advantages such as low energy consumption and direct utilization of solar energy, it still faces challenges in practical applications, including high recombination rates of photogenerated carriers, low degradation efficiency for long-chain alkanes, and poor water resistance. Photothermal synergistic catalysis technology combines the core advantages of photocatalysis and thermocatalysis, utilizing solar energy to drive the reaction and enhancing reaction rate and selectivity under moderate heating conditions, making it an effective way to achieve efficient VOCs degradation and carbon emission reduction. However, photothermal synergistic catalysis currently faces the following challenges: limited catalyst response range to broad-spectrum light; low efficiency of photogenerated electron-hole pair separation; insufficient adsorption and activation capacity for complex VOCs molecules; and an unclear mechanism of photothermal synergy. Therefore, there is an urgent need to construct broad-spectrum light-absorbing and highly efficient thermocatalytic materials, optimize the reaction interface design, strengthen the photothermal synergy mechanism, and break through efficiency bottlenecks in order to promote industrial applications.

[0004] Co3O4 spinel oxide is widely used in the thermocatalytic oxidation of VOCs due to its excellent redox properties and thermal stability. However, traditional Co3O4 is mostly in the form of dense nanoparticles or nanowires, relying solely on surface active sites for interaction with reactants, resulting in poor accessibility of internally dispersed active sites. The emergence of metal-organic frameworks (MOFs) has provided a new approach to solving this problem. Prussian blue analogues (PBAs), as a unique type of MOF, possess an open three-dimensional porous structure. During controlled calcination, the organic framework (cyanide ions) of PBAs is removed, while the framework topology of the precursor is fully inherited, ultimately leading to the derivation of Co3O4 nanoblocks with complex and interconnected three-dimensional channels. Therefore, Co3O4 derived from PBAs can not only promote mass transfer between reactants and products, but its surface porous structure can also provide single-atom anchoring sites. Furthermore, by precisely controlling the synthesis conditions of PBA precursors, PBA products with different morphologies and sizes can be prepared. These precursors retain their morphological characteristics completely after calcination, thus enabling precise "top-down" design of the final Co3O4 catalyst morphology and structure. Therefore, this study, through the pre-design of a multifunctional catalytic platform, lays a crucial structural foundation for the subsequent successful construction of the Pt1 / Co3O4 / GCN ternary composite system and the achievement of excellent photothermal synergistic catalytic performance.

[0005] Graphitic carbon nitride (GCN) is a non-metallic semiconductor photocatalytic material with excellent visible light response and chemical stability. However, it suffers from low photogenerated carrier separation efficiency, resulting in limited photocatalytic activity when used alone. Notably, GCN and Co3O4 have matched band structures, enabling efficient separation of photogenerated carriers through heterojunction construction. Furthermore, GCN's two-dimensional ultrathin sheet properties serve as an effective support, ensuring high dispersion and close contact between Co3O4 and Pt single atoms, thereby enhancing the synergistic effect between the components. In addition, the resulting heterointerface itself may also become a highly active thermocatalytic site.

[0006] Single-atom catalysts (SACs) exhibit great potential in enhancing adsorption, promoting O2 activation, and improving catalytic selectivity due to their extremely high atomic utilization and unique electronic structure. Therefore, in a Co3O4 / GCN heterojunction system, Pt single atoms were precisely anchored onto the surface of a Co3O4 cubic block using an in-situ ice crystal-assisted photoreduction method. This Pt single atom acts as an effective "electron bridge," significantly promoting the capture and migration of photogenerated electrons, thereby activating and cascading the Pt1 / Co3O4 / GCN ternary system. Under relatively low temperature and weak light intensity conditions, this catalyst demonstrates highly efficient and stable purification capabilities for high-concentration, large-molecule volatile organic compounds, achieving efficient synergy between light and heat energy.

[0007] This study is the first to design a novel catalyst, Pt1 / Co3O4 / GCN, and validates its excellent performance in the photothermal synergistic catalytic oxidation of high-concentration macromolecular VOCs (such as heptane and octane). Currently, there are no similar catalyst systems reported in the field of pollutant treatment. Throughout the entire process of catalyst preparation and application, this study adheres to the principles of green and sustainable chemistry, aiming to solve the problem of high energy consumption in traditional thermocatalysis by utilizing solar energy, a clean energy source. Summary of the Invention

[0008] The present invention aims to provide a highly active, highly stable catalytic material with excellent photothermal synergistic effect for the efficient purification of typical VOCs in catering fumes, such as macromolecular alkanes (heptane, octane, etc.), enabling the complete oxidation of high concentrations of VOCs under relatively low temperature and weak light intensity conditions, and exhibiting long-term cycle stability and water resistance.

[0009] A Pt1 / Co3O4 / GCN catalyst for photothermal synergistic catalytic oxidation of VOCs in the catering industry and its preparation method are disclosed below. (1) Preparation of two-dimensional ultrathin graphitic carbon nitride (GCN): Melamine was weighed into a crucible and calcined in a muffle furnace. The temperature was increased from room temperature to 550 ℃ at a heating rate of 1 ℃ / min and held for 4 h to obtain a bulk material of graphitic carbon nitride. After grinding it into powder, it was subjected to segmented heat treatment: first, the temperature was increased to 550 ℃ at room temperature at a heating rate of 1 ℃ / min and held for 2 h. After that, it was cooled to room temperature and calcined again under the same conditions for 2 h to finally obtain two-dimensional ultrathin GCN nanosheets. (2) Preparation of CoCo-PBA and its derivative Co3O4: Using cobalt salt and potassium cobalt cyanide as raw materials, firstly, Co(NO3)3·6H2O was dissolved in deionized water and ultrasonically dispersed to obtain solution A; then, K3[Co(CN)6] and polyvinylpyrrolidone (PVP) were dissolved in deionized water sequentially and ultrasonically stirred until dissolved to obtain solution B; under continuous stirring, solution A was slowly added dropwise to solution B, and stirring was continued at room temperature for 3.5 h. The resulting mixture was allowed to stand and age overnight, and finally washed three times with water and three times with alcohol, and dried at 80 °C to obtain the Co precursor of Prussian blue, namely CoCo-PBA precursor.

[0010] Further optimization: Solution A consists of 25 mL of deionized water for every 2.25 mmol Co(NO3)3·6H2O, and Solution B consists of 1 g of polyvinylpyrrolidone (PVP) and 25 mL of deionized water for every 5 mmol K3[Co(CN)6]. After Solution A is slowly added dropwise to Solution B, 5 mmol K3[Co(CN)6] is added dropwise for every 2.25 mmol Co(NO3)3·6H2O.

[0011] Nanobulb Co3O4 was prepared by the Prussian blue analogue (PBAs) self-sacrificial template method. Specifically, the CoCo-PBA precursor was placed in a crucible, and the muffle furnace was heated from room temperature to 400℃ at a heating rate of 1 °C / min and held for 2 h to obtain Co3O4 nanobulbs. (3) Preparation of Co3O4 / GCN heterojunction: Co3O4 nanobulbs were loaded onto the surface of GCN using ultrasound-assisted electrostatic self-assembly technology to form a heterojunction structure. Specifically, Co3O4 was ultrasonically dispersed in ethanol, denoted as suspension A; GCN was ultrasonically dispersed in ethanol, denoted as suspension B; suspension B was slowly added dropwise to suspension A under continuous stirring, and the mixture was stirred continuously at room temperature for 24 h to complete the loading process; finally, the product was washed three times with water and three times with alcohol, and dried at 80 °C to obtain the Co3O4 / GCN heterojunction.

[0012] The mass ratio of Co3O4 to GCN is 1-10%, preferably 5%.

[0013] (4) Preparation of single-atom Pt dispersed Pt1 / Co3O4 / GCN ternary composite catalyst: In-situ ice crystal-assisted photoreduction was used to reduce the Pt precursor to Pt single atoms (Pt1) and anchor them on the surface of Co3O4 nanoblocks. First, the Co3O4 / GCN heterojunction was weighed and ultrasonically dispersed in deionized water. H2PtCl6 solution was added under continuous stirring, and stirring was continued for 10 min. Then, the above mixed suspension was transferred to a centrifuge tube and rapidly frozen into solid ice crystals with liquid nitrogen. Under frozen conditions, it was irradiated with a 300 W xenon lamp until the ice crystals were completely melted. The obtained product was washed with water and alcohol three times each, and dried at 80 °C to obtain the Pt1 / Co3O4 / GCN catalyst.

[0014] The loading of Pt is adjusted according to the relationship between the amount of Co3O4 / GCN and H2PtCl6, with the mass percentage of Pt to Co3O4 / GCN being 0.1-0.3%, preferably 0.2%.

[0015] 0.1Pt1 / Co3O4 / GCN (referred to as 0.1% theoretical loading), 0.2Pt1 / Co3O4 / GCN (0.2% theoretical loading), 0.25Pt1 / Co3O4 / GCN (0.25% theoretical loading), and 0.3Pt1 / Co3O4 / GCN (0.3% theoretical loading).

[0016] The Pt1 / Co3O4 / GCN catalyst obtained in this invention provides a photothermal synergistic catalytic oxidation of VOCs in the catering industry.

[0017] Catalyst performance evaluation: To evaluate catalyst performance, this invention selected heptane and octane as probe molecules to represent VOCs in the catering industry, and tested them at a space velocity of 20,000 mL·g⁻¹. 1 ·h⁻ 1 The test was conducted under the following conditions: the gas mixture consisted of 3000 ppm heptane, 2000 ppm octane, or a mixture of the two (1500 ppm heptane and 1000 ppm octane), all containing 20 vol% O2 (with N2 as the equilibrium gas). The Pt1 / Co3O4 / GCN catalyst was subjected to full solar irradiation (300 mW·cm⁻¹). 2 The catalyst was used to catalyze the photothermal reaction of heptane and octane under synergistic heating conditions. Test results showed that the catalyst exhibited significantly higher catalytic activity than pure thermal catalysis under the same reaction atmosphere. Furthermore, the catalyst maintained highly efficient and stable photothermal catalytic activity during a 28-hour (aqueous)thermal stability test, indicating water resistance. The crystal structure and surface morphology of the catalyst were characterized in detail using X-ray diffraction (XRD), high-resolution high-angle annular dark-field scanning electron microscopy (HAADF-STEM), and energy-dispersive X-ray spectroscopy (EDX). The specific surface area, pore volume, and pore size distribution of the catalyst were characterized using nitrogen adsorption-desorption isotherms and the corresponding BJH pore size distribution. Electron paramagnetic resonance (EPR) spectroscopy was used to investigate the changes in active free radicals under dark or light conditions and to reveal the photothermal synergistic mechanism. The performance of the catalyst in photothermal catalytic elimination of VOCs (heptane and octane) from cooking fumes was evaluated using Shimadzu GC-2014C gas chromatography (GC).

[0018] This invention successfully developed a Pt1 / Co3O4 / GCN ternary composite catalyst with high photothermal synergistic catalytic performance, suitable for the efficient degradation of typical VOCs (heptane and octane) in restaurant fumes. This catalyst exhibits excellent catalytic activity, stability, and water resistance under low temperature and light conditions, showing promising application prospects. Under simulated sunlight, it demonstrates excellent low-temperature catalytic activity for high concentrations of heptane (3000 ppm). T 90% = 195 °C), stability and water resistance.

[0019] This invention further provides new ideas and methodological support for the design and development of spinel-semiconductor composite photothermal catalysts modified with single atoms. Attached Figure Description

[0020] Figure 1 The graphs show the performance evaluation of various catalysts for the catalytic oxidation of heptane under darkness or simulated sunlight. Figure a compares the performance of Co3O4, GCN, and different ratios of Co3O4 / GCN composite catalysts at 100 mW / cm². 2 Catalytic activity was evaluated under light intensity and 3000 ppm heptane conditions, with 5 wt% Co3O4 / GCN exhibiting the best activity; b shows the effect of introducing different loadings of Pt single atoms on catalyst activity, with 0.2 wt% Pt1 / Co3O4 / GCN showing the best catalytic activity under the same reaction conditions; c compares the optimal 0.2Pt1 / Co3O4 / GCN catalyst at 100 and 300 mW / cm². 2 The photothermal synergistic catalytic performance under high light intensity, compared with that of pure thermocatalysis, highlights the enhancing effect of light intensity on reaction activity and its contribution to the photothermal synergistic mechanism.

[0021] Figure 2 The figure shows the performance evaluation of the Pt1 / Co3O4 / GCN catalyst for the catalytic oxidation of heptane under different reaction conditions. Among them, a shows the effect of heptane concentration on the conversion rate under a fixed light intensity; b shows the regulatory effect of light intensity on catalyst activity under a fixed heptane concentration; c shows the catalytic performance of the catalyst in single heptane, single octane, and heptane / octane mixed atmospheres, revealing the obvious competitive adsorption behavior between different VOCs molecules.

[0022] Figure 3 The X-ray diffraction patterns of the Co3O4, GCN, Co3O4 / GCN, and Pt1 / Co3O4 / GCN catalysts are shown to analyze the crystal phase structure of each catalyst, indicating that the Pt species exist in a highly dispersed form.

[0023] Figure 4 The images show transmission electron microscopy (TEM) images and EDX elemental distribution maps of each catalyst. The results show that pure Co3O4 exhibits a nanobulb morphology and can be successfully loaded onto two-dimensional GCN sheets. Furthermore, aberration-corrected electron microscopy was used to observe highly dispersed Pt single atoms on the Co3O4 / GCN support.

[0024] Figure 5The nitrogen adsorption-desorption isotherms and corresponding BJH pore size distribution diagrams for each catalyst are presented to characterize the specific surface area, pore volume, pore size distribution, and other textural properties of each catalyst. For quantitative comparison, Appendix Table 1 summarizes the specific textural parameters of each catalyst obtained from this analysis and lists the actual Pt loading.

[0025] Figure 6 Electron paramagnetic resonance (EPR) spectroscopy was used to compare the generation of active species in the catalyst under dark and light conditions. Among them, the ×O2⁻ signal (b) generated by Pt1 / Co3O4 / GCN under light was the most significant, while the ×OH signal (a) was weaker. This confirmed that light can effectively excite and generate a large amount of ·O2⁻, which plays a key role in improving the photothermal catalytic performance.

[0026] Figure 7 The results of stability and water resistance tests on the catalyst were presented, and its performance degradation under long-term reaction and humidity conditions was evaluated. The results confirmed that the catalyst has excellent water resistance and regeneration ability. Detailed Implementation

[0027] The preparation method and application effects of the catalyst material will be described in detail below with reference to specific embodiments and accompanying drawings. These embodiments are intended to demonstrate the specific implementation methods and practical application effects of the present invention. Furthermore, it should be noted that they are only used to help understand the technical content of the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0028] Example 1 (Comparative Example): Preparation of Co3O4 / GCN 0.5 g of Co3O4 was ultrasonically dispersed in 50 mL of ethanol to obtain suspension A; separately, 25 mg of GCN (5 wt% relative to the mass of Co3O4) was ultrasonically dispersed in 50 mL of ethanol to obtain suspension B. Suspension B was slowly added dropwise to suspension A under continuous stirring, and the mixture was stirred at room temperature for 24 h to complete the loading process. Finally, the product was washed three times with water and three times with alcohol, and dried at 80°C to obtain a Co3O4 / GCN-5% heterojunction; different types can be prepared using the above method.

[0029] Example 2: Preparation of Pt1 / Co3O4 / GCN Different proportions of the Co3O4 / GCN-5% complex were dispersed in 30 mL of deionized water. An appropriate amount of chloroplatinic acid was added under continuous stirring. The suspension was rapidly frozen into a solid using liquid nitrogen. Then, the mixture was irradiated under a xenon lamp for 1 h to carry out a photoreduction reaction. Finally, the product was centrifuged, washed, and dried to obtain the Pt1 / Co3O4 / GCN-5% catalyst (theoretically, the loading of Pt on Co3O4 / GCN-5% ranges from 0.1 to 0.3 wt%).

[0030] Example 3 (Comparative Example): Preparation of Pt1 / Co3O4 Co3O4 was dispersed in 30 mL of deionized water, and an appropriate amount of chloroplatinic acid was added under continuous stirring (to make the theoretical loading of Pt on Co3O4 0.2 wt%). The suspension was rapidly frozen into a solid using liquid nitrogen, and then photoreduction reaction was carried out by irradiation under a xenon lamp for 1 h. Finally, the product was centrifuged, washed and dried to obtain 0.2Pt1 / Co3O4.

[0031] Example 4 (Comparative Example): Preparation of Pt1 / GCN GCN was dispersed in 30 mL of deionized water, and an appropriate amount of chloroplatinic acid was added under continuous stirring (to make the theoretical loading of Pt on GCN 0.2 wt%). The suspension was rapidly frozen into a solid using liquid nitrogen, and then photoreduction reaction was carried out under xenon lamp for 1 h. Finally, the product was centrifuged, washed and dried to obtain 0.2Pt1 / GCN.

[0032] Example 5: Catalytic performance test The photothermal catalytic performance of the catalyst for heptane was evaluated in a fixed-bed reactor, a tubular structure measuring 12 mm long, 12 mm wide, and 1 mm thick, operating at atmospheric pressure. The catalyst received illumination through a light-transmitting window in the reactor sidewall. A 300 W xenon lamp (PLS-SXE300D / 300DUV, Beijing Perfect Light; wavelength range 320-2500 nm) was used to simulate the solar energy source. The actual light power density of the xenon lamp was calibrated using a power meter (PM100D + S425C, Thorlabs). The temperature of the reaction heating process was controlled in the furnace (reaction tube located inside the furnace) by a programmable temperature controller. A thermocouple was inserted into the furnace / reactor tube, with its temperature sensing end directly contacting the catalyst bed, to monitor and provide feedback control of the furnace heating power before the reaction. Approximately 50 mg of catalyst (40-60 mesh) was mixed thoroughly with quartz sand and then loaded into the reactor. The gas mixtures were: 3000 ppm heptane + 20 vol% O2 + N2 (equilibrium gas), 2000 ppm octane + 20 vol% O2 + N2 (equilibrium gas), or 1500 ppm heptane + 1000 ppm octane + 20 vol% O2 + N2 (equilibrium gas), with a space velocity of 20,000 mL / (g·h) under all reaction conditions. The photothermal catalytic activity of each catalyst under different light intensities is shown in Table 1 below.

[0033] catalyst <![CDATA[ T 90% (°C)]]> <![CDATA[Light intensity (mW / cm 2 ).]]> <![CDATA[Co3O4]]> 330 100 GCN 400 100 <![CDATA[Co3O4 / GCN]]> 260 100 <![CDATA[0.2Pt1 / Co3O4 / GCN-5%]]> 220 100 <![CDATA[0.2Pt1 / Co3O4 / GCN-5%]]> 195 300 <![CDATA[0.2Pt1 / Co3O4 / GCN-5%]]> 235 0 The results show that the Pt1 / Co3O4 / GCN catalyst of the present invention has significant low-temperature catalytic activity for VOCs under photothermal synergistic conditions.

[0034] Example 6: Catalyst Stability Test To evaluate the stability and water resistance of the 0.2Pt1 / Co3O4 / GCN-5% catalyst, it was first tested at 195 °C and 300 mW / cm². 2 Under light intensity conditions, the catalytic activity remained stable for 11 hours. Subsequently, 5 vol% water vapor was continuously introduced into the reaction atmosphere, and the water vapor was cut off after 6 hours. During the water vapor introduction process, the heptane conversion rate remained at 68%-70%, and the catalyst activity immediately returned to the original level after the water vapor was stopped. Then, in a continuous 28-hour cycle test, the 0.2Pt1 / Co3O4 / GCN-5% catalyst exhibited excellent stability, good water resistance, and regeneration ability.

[0035]

Claims

1. A method for the preparation of a Pt1 / Co3O4 / GCN catalyst for the photo-thermo-catalytic oxidation of catering industry VOCs, characterized by, The specific steps are as follows: (1) Preparation of two-dimensional ultra-thin graphite phase carbon nitride GCN; (2) Preparation of CoCo-PBA and its derivative Co3O4: Take cobalt salt and potassium cobalt cyanide as raw materials, first, dissolve Co(NO3)3·6H2O in deionized water, and ultrasonic dispersion to obtain solution A; then, K3[Co(CN)6] and polyvinylpyrrolidone (PVP) are sequentially dissolved in deionized water, and ultrasonic stirring is carried out until dissolution to obtain solution B; under continuous stirring, solution A is slowly added to solution B, and stirring is continued at room temperature for 3.5 h, the obtained mixture is left to stand overnight, and finally washed with water and alcohol each three times, dried at 80°C to obtain the Co precursor of Prussian blue, namely CoCo-PBA precursor; Preparation of nanoblock Co3O4 by Prussian blue analog (PBA) self-sacrifice template method, namely, the CoCo-PBA precursor is placed in a crucible, the muffle furnace is heated from room temperature to 400°C at a heating rate of 1 °C / min, and the temperature is kept for 2 h to obtain Co3O4 nanoblocks; (3) Preparation of Co3O4 / GCN heterojunction: Co3O4 nanoblocks are loaded on the surface of GCN by ultrasonic assisted electrostatic self-assembly technology to form a heterojunction structure; namely, Co3O4 is ultrasonically dispersed in ethanol, denoted as suspension A; GCN is ultrasonically dispersed in ethanol, denoted as suspension B; under continuous stirring, suspension B is slowly added to suspension A, and the mixture is continuously stirred at room temperature for 24 h to complete the loading process; Finally, the product is washed with water and alcohol each three times, and dried at 80°C to obtain the Co3O4 / GCN heterojunction; The mass ratio of Co3O4 and GCN is 1-10%; (4) Preparation of Pt1 / Co3O4 / GCN ternary composite catalyst with single atom Pt dispersion: Pt precursor is reduced to Pt single atom (Pt1) and anchored on the surface of Co3O4 nanoblocks by in-situ ice crystal assisted photoreduction method; first, weigh the Co3O4 / GCN heterojunction and ultrasonically disperse it in deionized water, and add H2PtCl6 solution under continuous stirring, continue stirring for 10 min; then, the above mixed suspension is transferred to a centrifuge tube, and is quickly frozen into solid ice crystals with liquid nitrogen; irradiate with a 300 W xenon lamp under frozen state until the ice crystals completely melt, and the obtained product is washed with water and alcohol each three times, and dried at 80°C to obtain the Pt1 / Co3O4 / GCN catalyst.

2. The method of claim 1, wherein: Step (1) Preparation of two-dimensional ultra-thin graphite phase carbon nitride GCN: weigh the melamine in the crucible and place it in the muffle furnace, heat it from room temperature to 550°C at a rate of 1 ℃ / min, and keep the temperature for 4 h to obtain a block of graphite phase carbon nitride, grind it into powder, and then perform staged heat treatment: first, heat it from room temperature to 550°C at a rate of 1 ℃ / min, and keep the temperature for 2 h, then cool it to room temperature, and heat it again under the same conditions for 2 h, finally obtain two-dimensional ultra-thin GCN nanosheets.

3. The method of claim 1, wherein: In step (2), solution A is 25 mL deionized water for every 2.25 mmol Co(NO3)3·6H2O, and solution B is: 1 g polyvinylpyrrolidone (PVP) for every 5 mmol K3[Co(CN)6], 25 mL deionized water; solution A is slowly added to solution B, and for every 2.25 mmol Co(NO3)3·6H2O, 5 mmol K3[Co(CN)6] is used.

4. The method of claim 1, wherein: In step (3), the mass ratio of Co3O4 and GCN is 5%.

5. The method of claim 1, wherein: The loading amount of Pt is adjusted according to the amount of Co3O4 / GCN and H2PtCl6, and the mass percentage of Pt to Co3O4 / GCN is 0.1-0.3%, preferably 0.2%.

6. A Pt1 / Co3O4 / GCN catalyst prepared according to the method of any one of claims 1-5.

7. Use of the Pt1 / Co3O4 / GCN catalyst prepared according to the method of any one of claims 1-5 for photo-thermal synergistic catalytic oxidation of VOCs in the catering industry.

8. Use according to claim 7, the light being sunlight or a xenon lamp, the light intensity being 100-300 mW-cm ⁻2 , T 90% being 195-220°C.

Images