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CN-119793508-B - Biomass-derived in-situ nitrogen-phosphorus doped carbon material supported iron-based catalyst and preparation and application thereof

CN119793508BCN 119793508 BCN119793508 BCN 119793508BCN-119793508-B

Abstract

The invention discloses a biomass-derived in-situ nitrogen-phosphorus doped carbon material supported iron-based catalyst, and preparation and application thereof. The preparation method comprises the steps of weighing biomass, crushing and grinding the biomass to below 200 meshes, adding a solvent, adding an aqueous solution after the biomass is fully dispersed and activated, stirring and mixing the mixture uniformly, magnetically stirring the mixture at 20-50 ℃ for 8-15 hours, adjusting the pH value of the mixture to be more than 9 by an alkaline reagent to form gel, freeze-drying the gel, performing microwave treatment, performing hydrothermal reaction, filtering and washing to obtain a precursor, drying the precursor, calcining the precursor at a high temperature under an inert atmosphere, and cooling the precursor to obtain the biomass-derived in-situ nitrogen-phosphorus doped carbon material loaded iron-based photocatalyst. The invention provides application of the biomass-derived in-situ nitrogen-phosphorus doped carbon material loaded iron-based photocatalyst in photocatalytic reduction of CO 2 , which has good cycling stability and high yield of target products.

Inventors

  • WANG XIAOHUA

Assignees

  • 同济大学浙江学院

Dates

Publication Date
20260512
Application Date
20241220

Claims (10)

  1. 1. A preparation method of a biomass-derived in-situ nitrogen-phosphorus doped carbon material loaded iron-based photocatalyst is characterized by comprising the following steps: Weighing biomass, crushing and grinding the biomass to below 200 meshes, adding a solvent, after the biomass is fully dispersed and activated, adding an iron-containing aqueous solution, wherein the solute of the iron-containing aqueous solution is ferric salt and/or ferrous salt, the total concentration is 0.5-3 mol/L, stirring and mixing uniformly, magnetically stirring the mixture at 20-50 ℃ for 8-15 h, regulating the PH value to be more than 9 by an alkaline reagent to form gel, freeze-drying the gel, carrying out microwave treatment at 400-800W min, carrying out hydrothermal reaction at 160-200 ℃ for 8-15 h, filtering and washing to obtain a precursor, drying the precursor, heating the precursor to 700-950 ℃ in an inert gas atmosphere at a heating rate of 3-15 ℃, calcining for 0.5-2.5 h, and cooling to obtain the biomass-derived in-situ nitrogen-phosphorus doped carbon material loaded iron-based photocatalyst, wherein the biomass-derived in-situ nitrogen-phosphorus doped carbon material loaded photocatalyst simultaneously contains zero-valent iron, divalent iron and trivalent iron; The biomass is one of ① vinasse, a mixture of ② soybean powder and humus according to a mass ratio of 1:1, and a mixture of ③ vinasse and brown sugar according to a mass ratio of 5:1; the solvent is selected from any one of water, ethanol, 1-5 vol% glutaraldehyde aqueous solution, 1-5 vol% formaldehyde aqueous solution and 1-5 vol% acetone aqueous solution; The alkaline reagent is any one or more of 1-6M ammonia water, 1-6M sodium hydroxide aqueous solution, 1-6M potassium hydroxide aqueous solution, 1-6M sodium carbonate aqueous solution and 1-6M sodium bicarbonate aqueous solution; The feeding ratio of the biomass to the solvent to the aqueous solution is (2-10) g (2-25) g (10-40) mL.
  2. 2. The method according to claim 1, wherein the iron salt is one or more of ferric chloride, ferric sulfate and ferric nitrate, and the ferrous salt is one or more of ferrous chloride, ferrous sulfate, ferrous acetate and ferrous oxalate.
  3. 3. The method according to claim 2, wherein the solute in the aqueous iron-containing solution is a ferrous salt.
  4. 4. The method of claim 1, wherein the temperature is raised to 750-850 ℃ in a nitrogen atmosphere at a rate of 3-10 ℃ per minute, and the mixture is calcined for 1-2 hours.
  5. 5. The method of claim 4, wherein the temperature is raised to 750-850 ℃ in a nitrogen atmosphere at a rate of 5-10 ℃ per minute, and the mixture is calcined for 1-2 hours.
  6. 6. The method of claim 1, wherein the biomass is distillers' grains, the solvent is 3vol% formaldehyde aqueous solution, 5vol% glutaraldehyde aqueous solution or 5vol% acetone aqueous solution, the molten iron-containing solution is 1.5M ferrous chloride aqueous solution, the alkaline agent is 5M KOH aqueous solution or 5M ammonia water, the temperature is raised to 750-850 ℃ in a nitrogen atmosphere at a rate of 3-10 ℃ per minute in the preparation process, the calcination is carried out for 1-2 hours, and the charging ratio of the biomass, the solvent and the molten iron-containing solution is 5-10 g:20g:15mL.
  7. 7. The method of claim 6, wherein the biomass is distillers' grains, the solvent is 3vol% formaldehyde aqueous solution, the molten iron-containing solution is 1.5M ferrous chloride aqueous solution, the alkaline reagent is 5M KOH aqueous solution or 5M ammonia water, the temperature is raised to 850 ℃ in a nitrogen atmosphere at a rate of 8-10 ℃ per minute in the preparation process, the biomass is calcined for 1-1.5 h, and the charging ratio of the biomass, the solvent and the molten iron-containing solution is 5-10 g:20g:15mL.
  8. 8. The method of claim 1, wherein the biomass is a mixture of soybean powder and humus in a mass ratio of 1:1, the solvent is water, the aqueous iron-containing solution is 2.0M oxalic acid sub-aqueous solution, the alkaline agent is 6M ammonia water, the temperature is increased to 750 ℃ in a nitrogen atmosphere at a rate of 5 ℃ per minute in the preparation process, the biomass is calcined at 2h, and the charging ratio of the biomass, the solvent and the aqueous iron-containing solution is 6g:30g:15mL.
  9. 9. A biomass-derived in-situ nitrogen-phosphorus doped carbon material supported iron-based photocatalyst prepared according to the method of any one of claims 1-8.
  10. 10. Use of the biomass-derived in-situ nitrogen-phosphorus doped carbon material supported iron-based photocatalyst of claim 9 in photocatalytic reduction of CO 2 .

Description

Biomass-derived in-situ nitrogen-phosphorus doped carbon material supported iron-based catalyst and preparation and application thereof Technical Field The invention relates to a biomass-derived in-situ nitrogen-phosphorus doped carbon material supported iron-based catalyst, a preparation method thereof and an application thereof in photocatalytic reduction of CO 2. Background Due to the large amount of fossil fuels used, the CO 2 emissions exceed the processing capacity of nature, resulting in global warming, which poses a threat to the environment and ecology. Much research has been focused around reducing CO 2 emissions, capturing CO 2, and CO 2 conversion and utilization deployment. Among them, the conversion of CO 2 into high value-added fuels or chemicals plays an important role in solving the problems of energy supply and environmental pollution, and researchers have generally used thermocatalysts, electrocatalytic and photocatalytic realization. Compared with thermocatalysis and electrocatalytic, the technology for realizing photocatalytic reduction of CO 2 by utilizing ultraviolet or visible light to drive light-generated electrons has the advantages of mild operation conditions, low energy consumption, greenness, no pollution and the like, and is widely focused by researchers. However, single semiconductor materials generally have the problems of too wide or too narrow band gap width, insufficient light absorption or light response range, easy recombination of photo-generated electron pairs, poor conductivity, insufficient potential of a negative electrode for reducing CO 2 and the like, so that the problems of poor photocatalytic activity, poor stability and the like are caused. Many studies aim to enhance light absorption, modulate band gap width, increase defect structure, change or modify active center, accelerate electron transfer, inhibit recombination of photo-generated electron pairs, enhance activated adsorption of substrate molecules, thereby improving photocatalytic activity by constructing heterojunction, plasma modification, composite carbon material or porous material, etc. For example, chinese patent (202110057935.3) improved CdS photocatalytic performance by complexing CdS with MOF-808 and RGO to obtain lower band gap values than pure CdS. Chinese patent (20201108636. X) uses modified graphite carbon nitride (gC 3Nx) with nitrogen-containing defect structure and iron oxide (Fe 2O3) to obtain the Z-type composite catalyst for producing ammonia by photocatalytic nitrogen fixation. However, the problems of low activity of the photocatalyst, serious photo-corrosion, poor stability of the catalyst and the like still exist. The carbon material has acid resistance and good conductivity, can be used as a carrier to well disperse active components, and particularly can be used for remarkably improving the electronic structure of the carbon material by doping the carbon material with hetero atoms to form an electronic structure with uneven charge distribution, so that the adsorption and activation capability of the carbon material to substrate molecules are enhanced, and the carbon material has an electron density regulating effect on the active components. In summary, the technical problems to be solved by the invention are as follows: a preparation method of the biomass-derived in-situ nitrogen-phosphorus doped carbon material loaded mixed valence iron-based photocatalytic material is developed, and the photocatalytic material prepared by the method can be applied to photocatalytic reduction of carbon dioxide, and has the advantages of higher photocatalytic performance and better stability. Disclosure of Invention The invention aims to provide a preparation method of an in-situ nitrogen-phosphorus doped carbon material loaded iron-based photocatalyst derived from biomass, which aims to solve the problems of high cost, complicated steps, uneven doping, high environmental pressure and the like caused by taking an organic or inorganic chemical reagent as a raw material or an activating agent in the existing preparation method of the nitrogen-phosphorus doped carbon material. The second object of the invention is to provide a biomass-derived in-situ nitrogen-phosphorus doped carbon material supported iron-based photocatalyst. The invention further aims to provide an application of the biomass-derived in-situ nitrogen-phosphorus doped carbon material supported iron-based photocatalyst in photocatalytic reduction of CO 2. In order to achieve the aim of the invention, the invention adopts the following technical scheme: in a first aspect, the invention provides a preparation method of a biomass-derived in-situ nitrogen-phosphorus doped carbon material supported iron-based photocatalyst, which comprises the following steps: Weighing biomass, crushing and grinding the biomass to below 200 meshes, adding a solvent, after the biomass is fully dispersed and activated, adding an iron-containing aqueous