CN-121988396-A - Preparation method and application of BiOCOOH-A-Fe composite photocatalyst

Abstract

The invention discloses a preparation method and application of BiOCOOH-A-Fe photocatalyst, which comprises the specific preparation process that pre-prepared BiOCOOH is taken as a carrier, an iron monoatom is stably anchored on the surface of BiOCOOH through the axial coordination action of APTES, and the APTES can realize the firm loading of BiOCOOH on the iron monoatom, so that the prepared composite photocatalyst has better stability and catalytic activity, and meanwhile, the end group of-NH 2 which does not participate in coordination in the APTES can obviously enhance the adsorption of NO 3 ‑ , so that the nitrogen selectivity in the photocatalytic reduction of nitrate by the composite catalyst can be improved. The composite photocatalyst has the advantages of wide light response range, high quantum efficiency and the like, can efficiently and quickly reduce nitrate in water into nitrogen under illumination conditions, has good stability, can be recycled for multiple times, and is an ideal water treatment photocatalyst.

Inventors

• ZHANG XIA
• HAN JIAXIN
• FAN JING
• ZHU GUIFEN
• ZHANG KAIGE
• LI TIEMEI

Assignees

• 河南师范大学

Dates

Publication Date

20260508

Application Date

20251230

Claims (6)

1. 1. A preparation method of BiOCOOH-A-Fe composite photocatalyst is characterized in that BiOCOOH is used as a carrier, an iron single atom is stably anchored and supported on the surface of BiOCOOH through the axial coordination action of 3-aminopropyl triethoxysilane APTES, and finally the BiOCOOH-A-Fe composite photocatalyst is obtained, wherein 3-aminopropyl triethoxysilane APTES can realize firm loading of BiOCOOH on the iron single atom, so that the prepared composite photocatalyst has better stability and catalytic activity, and meanwhile, the end group of-NH 2 which does not participate in coordination in the 3-aminopropyl triethoxysilane APTES can obviously enhance the adsorption of NO 3 - , so that the nitrogen selectivity in the process of photocatalytic reduction of nitrate by the composite catalyst can be improved, and meanwhile, the requirement of reaction on hole sacrificial reagent is reduced.
2. 2. The preparation method of the BiOCOOH-A-Fe composite photocatalyst according to claim 1, wherein the morphology of the BiOCOOH-A-Fe composite photocatalyst shows a flower-like microsphere structure assembled by ultrathin nano sheets, the surface of the BiOCOOH-A-Fe composite photocatalyst has clear lattice fringes, the crystal plane spacing between a (110) crystal plane and a (102) crystal plane is 0.28nm and 0.31nm respectively, the XRD spectrum of the BiOCOOH-A-Fe composite photocatalyst has Jiang Yanshe peaks at 24.1 DEG, 28.7 DEG and 32.4 DEG, which correspond to (101), (102) and (110) crystal planes of the composite photocatalyst respectively, and binding energy exists at 159.1eV, 164.5eV, 529.6eV, 530.8eV, 532.1eV, 706.7eV, 710.8eV, 715.9eV, 724.3eV and 731.9eV in the XPS spectrum of the BiOCOOH-A-Fe composite photocatalyst.
3. 3. The preparation method of the BiOCOOH-A-Fe composite photocatalyst according to claim 1 is characterized by comprising the specific preparation steps of dissolving Bi (NO 3 ) 3 ·5H 2 O) in DMF, sequentially adding glycol and deionized water, stirring to form a uniform colorless solution, transferring the solution into a hydrothermal reaction kettle for hydrothermal reaction, naturally cooling to room temperature after the reaction is finished, separating and washing precipitate, drying to obtain BiOCOOH carrier, dissolving FeCl 3 ·6H 2 O in absolute ethyl alcohol, adding silane coupling agent APTES, uniformly mixing to form solution A, dispersing BiOCOOH carrier in absolute ethyl alcohol, dropwise adding the solution A under stirring, stirring at room temperature to obtain solution B, subsequently adding sodium borohydride solution into the solution B, continuing stirring for reaction, separating precipitate after the reaction is finished, washing and drying to obtain the BiOCOOH-A-Fe composite photocatalyst.
4. 4. The use of BiOCOOH-a-Fe composite photocatalyst prepared by the method according to any one of claims 1-3 in photocatalytic reduction reactions.
5. 5. The use of BiOCOOH-a-Fe composite photocatalyst prepared by the method according to any one of claims 1-3 in selective photocatalytic reduction of nitrate.
6. 6. The use of BiOCOOH-A-Fe composite photocatalyst prepared by the method according to any one of claims 1-3 in selective photocatalytic purification of nitrate-polluted water.

Description

Preparation method and application of BiOCOOH-A-Fe composite photocatalyst Technical Field The invention belongs to the technical field of inorganic environment-friendly composite photocatalytic materials, and particularly relates to a preparation method and application of BiOCOOH-A-Fe composite photocatalyst. Background Nitrate pollution has become a ubiquitous environmental problem due to the widespread use of nitrogen fertilizers in agriculture and the improper discharge of industrial wastewater. Nitrate is less toxic by itself, but can be converted to nitrite in the environment, which can not only lead to methemoglobinemia, but also present a risk of carcinogenesis. The conventional nitrate removal method, such as physical adsorption, biodegradation, chemical reduction and the like, has the defects of low removal efficiency, long treatment period, easiness in secondary pollution and the like. Therefore, it is of great importance to develop efficient and environmentally friendly nitrate removal technology. Photocatalysis, which is a green technology, has been widely used for removing nitrate in water bodies. The materials currently used for photocatalytic reduction of nitrate mainly comprise titanium dioxide, bismuth vanadate and the like. Although some of the reported catalysts exhibit better performance, there are problems of slow reaction kinetics, large amounts of hole sacrificial agents, and the like. Traditional solutions focus on reducing the material band gap and promoting charge transfer by element doping or heterojunction construction, thereby improving the reducing capability of the catalyst. In addition, there are studies to achieve higher nitrate removal efficiency and nitrogen selectivity by introducing noble metals, but its practical application is often limited by high material costs. Enhancing the adsorption capacity of the photocatalytic material to nitrates, even at low concentrations of hole sacrificial agents, helps achieve faster reaction kinetics and higher nitrogen selectivity. Therefore, from the aspects of economy and environmental friendliness, the development of the photocatalytic material with high nitrate affinity and low metal loading has important research value and application prospect. Bismuth formate (BiOCOOH) has been attracting attention due to its green elemental composition and unique layered structure. However, its practical application is still limited by its wide bandgap (about 3.2 eV), limited light absorption range (< 370 nm), and slow photogenerated charge transport efficiency. Currently, research to improve BiOCOOH photocatalytic performance has focused on constructing heterojunctions with narrow bandgap semiconductors. In recent years, monoatomic modification gradually becomes a promising modification strategy, and has the advantages of maximally improving the atom utilization rate and accelerating the photo-generated charge migration, so that the photocatalytic activity of the material is remarkably enhanced. In addition, the ability of the photocatalytic material to adsorb target substances is one of the key factors that affect the reaction rate and product selectivity. By carrying out functional modification on the surface of the material, the adsorption performance of the material on nitrate can be effectively improved, and the material has good application potential in the aspect of efficiently and directionally removing nitrate. The 3-aminopropyl triethoxy silane (APTES) can be used as an important silane coupling agent for surface modification of inorganic oxide, and the triethoxy silane group of molecules can generate condensation reaction with hydroxyl (-OH) on the surface of the material through silanol (-Si-OH) to form stable Si-O-covalent bond, so that the APTES can be firmly immobilized on the surface of the inorganic material. Meanwhile, the-NH 2 group at the tail end of APTES can be used as an active site for anchoring metal species such as iron (Fe), copper (Cu) and the like. Research shows that the catalytic activity, stability and selectivity of the catalyst can be effectively optimized by regulating and controlling the local coordination environment around single atoms. Currently, axially coordinated monoatomic iron catalysts have demonstrated good performance in a number of catalytic fields, but their application in photocatalytic nitrate removal remains to be explored in depth. The patent document CN201611141039.0 discloses a preparation method of porous bismuth dialkyl dithiocarbamate visible light catalyst, bismuth salt and dialkyl dithiocarbamate are respectively dissolved in solvent, the solution of dialkyl dithiocarbamate is added into bismuth salt solution drop by drop to produce yellow precipitate, or bismuth salt and powder of dialkyl dithiocarbamate are directly mixed, dry-ground or grinding aid is added to grind to obtain yellow powder, the porous bismuth dialkyl dithiocarbamate is obtained through filtering, washing and drying