A composite Pt / BiVO4 / FeCoO x Method for producing a material and use thereof

Abstract

The application discloses preparation and application of a spatially separated BiVO4 material. The BiVO4 material is rapidly and accurately synthesized through a microwave hydrothermal method, and the synthesized BiVO4 material is used as a base material BiVO4. Light makes the base material BiVO4 generate photoelectrons and photoholes. Due to the crystal face effect of the base material BiVO4, the photoelectrons and photoholes are directionally transferred to the (0 1 0) reduction crystal face and the (1 1 0) oxidation crystal face of the base material BiVO4. Then, the spatially separated Pt and FeCoO x bipartite cocatalyst, and finally a composite Pt / BiVO4 / FeCoO x material with spatial separation is realized. x The composite Pt / BiVO4 / FeCoO x material can effectively mineralize diclofenac sodium to CO2, and then reduce the CO2 to methanol and ethanol to realize resource recycling. The application realizes selective loading of a bipartite cocatalyst and high-selectivity one-pot conversion of pollutants into recyclable resources, and provides a new idea for design and application of an efficient catalyst.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of catalyst preparation, in particular to a composite Pt / BiVO4 / FeCoO x Preparation method of material and application thereof. BACKGROUND

[0002] In the 21st century, global energy supply and related environmental problems are the biggest technical challenges faced by chemists and technical experts. Our main energy comes from limited and non-renewable fossil fuels, such as coal, oil and natural gas. Moreover, the consumption of these fuels has caused a series of serious environmental problems, among which environmental pollution is an urgent problem to be solved. However, the current technology inevitably produces a large amount of greenhouse gas when dealing with environmental pollution, which seriously violates the concept of China's "double carbon plan". Therefore, it is very urgent to design a photocatalyst to effectively treat environmental pollution while slowing down the subsequent greenhouse effect.

[0003] In general, the key problem of realizing the simultaneous occurrence of environmental pollution and greenhouse effect is to realize the efficient separation of photo-generated electrons and holes and to reduce the competition of oxidation and reduction reactions. Among them, charge separation plays a key role in the solar energy conversion efficiency of semiconductor-based systems for solar energy power and solar fuel production through solar cells, photoelectrocatalysis and photocatalysis. As a key step of energy conversion, the electron-hole pairs generated by light absorption need to be separated and transferred to the surface of the semiconductor. Therefore, it is necessary to design and synthesize charge separation in-depth understanding of the internal of the semiconductor for the construction of efficient solar energy conversion system.

[0004] In order to synthesize photocatalysts with high efficient charge separation to improve photocatalytic performance, people have made great efforts. By introducing suitable cocatalysts, especially dual cocatalysts for reduction and oxidation half-reactions, has been proved to be a promising solution. Studies have shown that reduction / oxidation cocatalysts not only promote charge separation by capturing photo-generated electrons / holes, but also adjust surface reactivity by providing high active sites for adsorption and activation of reactant molecules. In the design of semiconductor-based photocatalyst dual cocatalysts, it is crucial to rationally construct reduction and oxidation cocatalysts on different sites, so that the reduction and oxidation half-reactions are spatially separated, which not only inhibits the charge recombination caused by the different migration directions of electrons and holes, but also prevents the reverse reaction caused by the distance between the reduction and oxidation products. Therefore, it is imperative to design and synthesize a photocatalyst with high efficient charge separation to effectively treat environmental pollution while slowing down the subsequent greenhouse effect.

[0005] In recent years, designing materials with spatial separation to realize efficient separation of electrons and holes has become a research hotspot in the field of photocatalysis. People are committed to developing a strategy to synthesize materials with spatially separated dual cocatalysts.

[0006] These strategies mainly include: (1) randomly modifying two cocatalysts on the surface of the photocatalyst. This method usually leads to direct contact between the oxidation center and the reduction center, which is not conducive to effective charge separation, and the oxidation reaction and the reduction reaction exist in competition, affecting the reaction activity; (2) by controlling the morphology of the carrier material, a hollow core-shell type photocatalyst is obtained, and different cocatalysts are decorated on the inner and outer surfaces of the hollow core-shell type photocatalyst. However, this method usually requires a complex synthesis process and a strong alkaline solution etching step to remove the hard template (such as SiO2). However, due to their respective limitations, these existing strategies cannot be directly applied to two-dimensional materials. SUMMARY

[0007] The purpose of the present application is to solve the technical problems existing in the prior art, and provide a composite Pt / BiVO4 / FeCoO x material preparation method and application thereof

[0008] To achieve the above-mentioned purpose, the technical scheme provided by the present application is: a composite Pt / BiVO4 / FeCoO x material preparation method, first, a BiVO4 material with tunable (0 1 0) reduction crystal face and (1 1 0) oxidation crystal face ratio is quickly and accurately synthesized by a microwave hydrothermal method, the synthesized BiVO4 material is used as a base material BiVO4, light makes the base material BiVO4 generate photoelectrons and photoholes, due to the crystal face effect of the base material BiVO4, the photoelectrons and photoholes will be directionally transferred to the (0 1 0) reduction crystal face and the (1 1 0) oxidation crystal face of the base material BiVO4, and then a Pt and FeCoO x bico-catalyst with spatial separation is directionally introduced by a photodeposition method, which accelerates the separation of photoelectrons and holes, effectively improves the transmission efficiency and separation efficiency of photo-generated carriers, and finally realizes the synthesis of the composite Pt / BiVO4 / FeCoO x material.

[0009] Preferably, the photodeposition method directionally introduces Pt and FeCoO x bico-catalyst with spatial separation is due to the crystal face effect of the base material BiVO4, so that Pt and FeCoO x selective deposition occurs, that is, Pt is deposited on the reduction (0 1 0) reduction crystal face and FeCoO x is deposited on the (1 1 0) oxidation crystal face.

[0010] Preferably, the composite Pt / BiVO4 / FeCoO x material has an electron lifetime of 5.16 μs.

[0011] The application further discloses a composite Pt / BiVO4 / FeCoO x application of the material, including the composite Pt / BiVO4 / FeCoO x prepared by the preparation method of the material, the composite Pt / BiVO4 / FeCoO x material, the composite Pt / BiVO4 / FeCoO x The material can effectively mineralize diclofenac sodium into CO2, and then reduce the CO2 into methanol and ethanol, so that resource recycling is realized.

[0012] Preferably, the degradation rate of diclofenac sodium is 69.82%, and the yield of methanol and ethanol can reach 2.89 and 13.15 mu mol -1 ·g -1 .

[0013] The application has the following beneficial effects:

[0014] 1. The composite Pt / BiVO4 / FeCoO x photocatalyst provided by the application has a crystal face effect, and the spatial separation of double cocatalysts accelerates the separation of photo-generated electrons and holes, realizes directional transmission of photo-generated charges, effectively improves the transmission efficiency and separation efficiency of photo-generated carriers, and provides a new material for solving current pollution and energy problems.

[0015] 2. The composite Pt / BiVO4 / FeCoO x material realizes efficient and non-interfering oxidation and reduction, efficiently mineralizes organic pollutants into CO2 and realizes resource utilization by synchronous reduction, provides a new idea for solving current pollution and energy problems. DETAILED DESCRIPTION

[0016] The accompanying drawings, which are included to provide a further understanding of the application, form a part of the application and, along with the specification, serve to explain the application. The illustrative embodiments of the present application and their description serve to explain the application and do not limit the application.

[0017] Figure 1 is an XRD pattern of the Pt / BiVO4 / FeCoO x catalyst synthesized by the two-step method in the application;

[0018] Figure 2 is an SEM pattern of the BiVO4 and Pt / BiVO4 / FeCoO x catalyst in the application;

[0019] Figure 3 is a Pt / BiVO4 / FeCoO xPt / BiVO4, BiVO4 / FeCoO catalyst and single self-catalyst x CO2 reduction diagram;

[0020] Figure 4 The best ratio of Pt / BiVO4 / FeCoO in this invention x Pt / BiVO4, BiVO4 / FeCoO catalyst and single self-catalyst x Pollutant degradation diagram;

[0021] Figure 5 The best ratio of Pt / BiVO4 / FeCoO in this invention x Fluorescence spectrum of the composite catalyst;

[0022] Figure 6 The best ratio of Pt / BiVO4 / FeCoO in this invention x Time-resolved fluorescence decay spectrum of the composite catalyst. DETAILED DESCRIPTION

[0023] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it should not be understood as a limitation on the scope of protection of the present invention.

[0024] Reference Figures 1-6 , a preferred embodiment of the present invention, a composite Pt / BiVO4 / FeCoO x The preparation method of the material is to first quickly and accurately synthesize BiVO4 material with a tunable ratio of (0 10) reduced crystal plane and (1 1 0) oxidized crystal plane by microwave hydrothermal method, and then use the synthesized BiVO4 material as the substrate material BiVO4. Irradiation causes the substrate material BiVO4 to generate photogenerated electrons and photogenerated holes. Due to the crystal plane effect of the substrate material BiVO4, the photogenerated electrons and photogenerated holes are directionally transferred to the (0 1 0) reduced crystal plane and (1 1 0) oxidized crystal plane of the substrate material BiVO4. Then, the spatially separated Pt and FeCoO are directionally introduced by photodeposition. x The dual co-catalyst accelerates the separation of photogenerated electrons and holes, effectively improving the transmission efficiency and separation efficiency of photogenerated carriers, and ultimately realizing the composite Pt / BiVO4 / FeCoO with spatial separation. x Synthesis of materials.

[0025] In this embodiment, the photodeposition method introduces Pt and FeCoO with spatial separation. xThe dual promoter is due to the crystal surface effect of the base material BiVO4, which makes Pt and FeCoO x Selective deposition occurs, that is, Pt is deposited on the reduced (0 1 0) crystal plane while FeCoO x Deposited on the (1 1 0) oxidized crystal surface.

[0026] In this embodiment, the composite Pt / BiVO4 / FeCoO x The material's electron lifetime can reach 5.16μs.

[0027] The present invention also discloses a composite Pt / BiVO4 / FeCoO x Application of materials, including any one of the above-mentioned composite Pt / BiVO4 / FeCoO x Composite Pt / BiVO4 / FeCoO prepared by material preparation method x Materials, composite Pt / BiVO4 / FeCoO x The material can effectively mineralize diclofenac sodium into CO2, and then reduce CO2 to methanol and ethanol, realizing resource recycling.

[0028] The antibiotic pollutants were efficiently mineralized to produce CO2 and H2O at the reducing end of BiVO4, and CO2 was highly selectively converted to methanol and ethanol at the oxidizing end of BiVO4.

[0029] In this embodiment, the degradation rate of diclofenac sodium is 69.82%, and the yields of methanol and ethanol can reach 2.89 and 13.15 μmol, respectively. -1 ·g -1 .

[0030] Reference Figures 1-2 In a preferred embodiment of the present invention, a dual-catalyst spatially separated Pt / BiVO4 / FeCoO was synthesized by microwave hydrothermal method combined with photodeposition method. x Materials. Reference Figures 3-6 , under visible light irradiation, Pt / BiVO4 / FeCoO x The material achieves directional transport of photogenerated charges, effectively improving the transport and separation efficiency of photogenerated carriers. This allows for highly selective, one-pot conversion of pollutants into recyclable resources, effectively treating pollutants while mitigating the greenhouse effect. Compared to pure BiVO4 or materials with only a single co-catalyst, it achieves superior pollutant degradation and simultaneous CO2 reduction for resource utilization.

[0031] XRD (X-ray diffraction) was used to determine the phase structure and crystal plane identity of the material. The instrument model used was Bruker, Germany.

[0032] The surface morphology of the material was determined by SEM (scanning electron microscope), and the instrument used was JFEI, Hillsboro, OR, USA.

[0033] The one-pot simultaneous redox test was carried out by connecting a glass sealed gas system, and the instrument used was Prefect Light, Beijing, Labsolar-III.

[0034] The pollutant degradation performance of the material was determined by liquid chromatography, and the instrument used was UHPLC-MS, Agilent, United States.

[0035] The CO2 reduction performance of the material was determined by online gas chromatography, and the instrument used was GC-7900, FID, HayeSep A, Ar and H2 carrier, Japan Shimadzu.

[0036] The electron transport performance of the material was determined by fluorescence spectrum, and the instrument used was PL, Hitachi F-4500.

[0037] The electron lifetime of the material was determined by time-resolved fluorescence decay spectrum, and the instrument used was FS5 fluorescence spectrometer, Edinburgh Instruments, 380 nm picosecond pulse diode laser (EPLED-380, maximum average power 40 mW as excitation source).

[0038] Example 1

[0039] First, BiVO4 materials with tunable (0 1 0) reduction crystal face and (1 1 0) oxidation crystal face ratio were synthesized by a microwave hydrothermal method, which were used as a substrate material to introduce Pt and FeCoO x Dual cocatalysts, due to the crystal face effect of the material, Pt and FeCoO x were selectively deposited, i.e. Pt was deposited on the reduction (0 1 0) reduction crystal face and FeCoO x was deposited on the (1 1 0) oxidation crystal face, finally realizing a composite Pt / BiVO4 / FeCoO x material with spatial separation.

[0040] The specific preparation method of the material in this example is as follows:

[0041] Preparation of BiVO4 material: 0.3 mmol of Bi(NO3)3.5H2O and 0.3 mmol of ammonium metavanadate NH4VO3 were weighed into 1 M nitric acid solution, stirred for 15 min, and then transferred into a 15 mL high-borosilicon microwave reactor. After pre-stirring for 3 min, the reaction was carried out at a reaction temperature of 70°C for 30 min, and a yellow suspension was finally obtained. The obtained mixture was filtered with ethanol and water and vacuum dried overnight. The obtained bright yellow powder was the BiVO4 material with crystal face effect.

[0042] Pt / BiVO4 / FeCoO x Preparation of the material: First, phosphate buffered saline PBS was prepared. 9.0466 g of sodium phosphate dibasic and 1.5487 g of citric acid were weighed and dissolved in 200 mL of deionized water. The obtained solution had a pH of about 6.1 and was left to stand for use. 50 mg of the above BiVO4 material with crystal face effect was dispersed in 50 mL of PBS buffer, and 5% Pt precursor chloroplatinic acid and FeCoO x precursor cobalt nitrate and potassium ferricyanide were added after stirring for 10 min. The obtained solution was placed under a 300 W Xe lamp with a wavelength range of 320 nm≤λ≤780 nm and an optical intensity of 160 mW / cm 2 for 15 min. Finally, the obtained liquid was filtered with ethanol and water and vacuum dried overnight. The obtained yellow powder was Pt / BiVO4 / FeCoO x material.

[0043] Preparation of BiVO4-L: 50 mg of the above BiVO4 material with crystal face effect was dispersed in 50 mL of PBS buffer without adding a cocatalyst precursor. The obtained solution was placed under a 300 W Xe lamp (wavelength range: 320 nm≤λ≤780 nm, optical intensity: 160 mW / cm 2 ) for 15 min. Finally, the obtained liquid was filtered with ethanol and water and vacuum dried overnight. The obtained yellow powder was the control group BiVO4-L material.

[0044] The experimental results are shown in Figure 1 Pt / BiVO4 / FeCoO x There were diffraction peaks matching BiVO4, and there were significant diffraction peaks corresponding to the oxidation crystal face (1 1 0) and the reduction crystal face (0 1 0) of BiVO4, respectively. Compared with pure BiVO4 and the control group BiVO4-L (without introducing double cocatalysts, pure BiVO4 light irradiation), no obvious characteristic peaks appeared, which confirmed that the synthesis method did not introduce additional impurities and the light irradiation reaction did not affect the exposed crystal face and surface structure of BiVO4.

[0045] As Figure 2 shown, BiVO4 material shows an octahedral material with well-defined exposed facets, the top and side are the reduced facet (0 1 0) and the oxidized facet (1 1 0), respectively. While introducing the dual cocatalyst Pt / BiVO4 / FeCoO x material shows a similar octahedral structure to BiVO4 material, indicating that the photocatalytic reaction does not change the morphology of BiVO4. Notably, there are obvious aggregated nanoparticles on the top of the octahedral BiVO4, which are attributed to Pt nanoparticles. While on the side of the octahedron, there is obvious deposition of blocky material, which is attributed to the FeCoO x material selectively deposited on the oxidized facet. The above results confirm the successful synthesis of Pt / BiVO4 / FeCoO x material and the spatial separation of the dual cocatalyst.

[0046] Example 2

[0047] The performance of pollutant degradation and simultaneous reduction of CO2 was tested in a pollution degradation and simultaneous reduction of CO2 performance test. A 300W Xe lamp (wavelength range 420nm≤λ≤780nm, light intensity 160mW / cm 2 ) was used as a simulated sunlight source. 20mg of catalyst was dispersed in 80mL of a solution containing 10mg / L DCF and 0.01M NaOH by magnetic stirring. The air was completely removed several times using a vacuum pump, and the entire reaction device was evacuated and a high-purity Ar stream was introduced into the system until the ambient pressure was reached. Before irradiation, the solution was stirred in the dark for 1h to allow the photocatalyst to reach adsorption-desorption equilibrium with the DCF solution. During the reaction, the temperature of the reaction solution was maintained at 6°C by an external condensate water flow to maintain the good light absorption capacity of the catalyst. Online gas chromatography was used to analyze the products methanol and ethanol. In order to obtain the liquid, a certain amount of solution was extracted from the reaction cell at a given time interval, and the reaction was terminated after adding methanol solution to the sample and mixing well. Subsequently, the concentration of DCF in the reaction system was measured by high performance liquid chromatography.

[0048] As Figures 3-4 shown, BiVO4 material shows an octahedral material with well-defined exposed facets, the top and side are the reduced facet (0 1 0) and the oxidized facet (1 1 0), respectively. While introducing the dual cocatalyst Pt / BiVO4 / FeCoO x has excellent DCF degradation and CO2 reduction effect under simulated sunlight irradiation, the DCF degradation rate is 69.82%, and the CO2 reduction to methanol and ethanol can reach 2.89 and 13.15μmol -1 .g -1 , which is much higher than that of Pt / BiVO4, BiVO4 / FeCoO x, confirming the two-step synthesis of Pt / BiVO4 / FeCoO x Due to the spatial separation of the oxidation co-catalyst and the reduction co-catalyst, as well as the crystal surface effect of the substrate material, efficient charge directional transfer is achieved, ultimately achieving efficient mineralization degradation of DCF pollutants and simultaneous CO2 reduction.

[0049] like Figures 5-6 The experimental results show that the fluorescence and transient fluorescence spectroscopy analysis confirms that compared with pure BiVO4 and BiVO4-L, Pt / BiVO4 / FeCoO x The efficient charge separation, low electron-hole pair recombination rate, and long electron lifetime of BiVO4 and BiVO4-L show no significant difference in the optical and transient fluorescence spectra, demonstrating that the efficient charge separation is due to the introduction of the oxidation and reduction co-catalysts and their spatial separation, rather than other intrinsic structural changes in BiVO4 caused by the light reaction.

[0050] Under the premise that no conflict occurs, those skilled in the art may freely combine and superimpose the above-mentioned additional technical features.

[0051] The above descriptions are only preferred embodiments of the present invention. Any technical solution that achieves the purpose of the present invention by substantially the same means shall fall within the scope of protection of the present invention.

Claims

1. A composite Pt / BiVO4 / FeCoO x Process for the preparation of a material, characterized in that: First, the BiVO4 material with adjustable ratio of (010) reduction crystal face and (110) oxidation crystal face is quickly and accurately synthesized by microwave hydrothermal method, the synthesized BiVO4 material is used as the base material BiVO4, and the base material BiVO4 generates photo-generated electrons and photo-generated holes under light irradiation, due to the crystal face effect of the base material BiVO4, the photo-generated electrons and photo-generated holes are directionally transferred to the (010) reduction crystal face and (110) oxidation crystal face of the base material BiVO4, then Pt and FeCoO x with spatial separation are directionally introduced by photodeposition method x material synthesis; Preparation of BiVO4 material: 0.3 mmol of Bi(NO3)3.5H2O and 0.3 mmol of ammonium metavanadate NH4VO3 were weighed into 1 M nitric acid solution, stirred for 15 min, and then transferred into a 15 mL high-boron silica microwave reactor. After pre-stirring for 3 min, the reaction was carried out at a reaction temperature of 70°C for 30 min. A yellow suspension was obtained. The obtained mixture was filtered with ethanol and water and vacuum-dried overnight. The obtained bright yellow powder was the BiVO4 material with a crystal face effect; Pt / BiVO4 / FeCoO x Preparation of material: First, phosphate buffer PBS was prepared, 9.0466 g of sodium phosphate dibasic and 1.5487 g of citric acid were weighed and dissolved in 200 mL of deionized water, the resulting solution pH was about 6.1, and it was left to stand for use. 50 mg of the above BiVO4 material with crystal face effect was dispersed in 50 mL of PBS buffer, 5% Pt precursor chloroplatinic acid and FeCoO x precursor cobalt nitrate and potassium ferricyanide, the resulting solution was fully stirred and placed in a 300 W Xe lamp with a wavelength range of 320 nm≤λ≤780 nm, light intensity 160 mW / cm 2 After 15 min of light, finally, the resulting liquid was filtered by ethanol and water and vacuum dried overnight, and the resulting yellow powder was Pt / BiVO4 / FeCoO x material.

2. A composite Pt / BiVO4 / FeCoO according to claim 1 x Process for the preparation of a material, characterized in that: Composite Pt / BiVO4 / FeCoO x The electronic lifetime of the material is 5.16 ps.

3. A composite Pt / BiVO4 / FeCoO x application of the material, including the composite Pt / BiVO4 / FeCoO x application of the material, including the composite Pt / BiVO4 / FeCoO x application of the material, including the composite Pt / BiVO4 / FeCoO Composite Pt / BiVO4 / FeCoO x The material can effectively mineralize diclofenac sodium to CO2, and then reduce CO2 to methanol and ethanol, thereby realizing resource recycling.

4. A composite Pt / BiVO4 / FeCoO according to claim 3 x Use of a material, characterized in that The degradation rate of diclofenac sodium was 69.82%, and the yield of methanol and ethanol reached 2.89 and 13.15 μmol, respectively -1 ·g -1 .

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