Catalyst for CO2 capture and conversion coupling with biomass oxidation, a preparation method therefor and an application thereof

A preparation method of a catalyst for CO2 capture and coupling conversion with biomass oxidation, characterized in that the preparation method comprises the following steps:

• A. dissolve soluble metal salts M2+ and M3+ in deionized water to prepare a solution A, wherein the molar ratio of M2+:M3+ is 2-4:1, and the anion is CO32−;
• the total concentration of M2+ and M3+ ions is 0.16-0.20 mol/L;
• M2+ is one or more selected from Zn2+, Co2+, Ni2+ and Cu2+;
• M3+ is one of Al3+, Fe3+ and Ga3+;
• B. dissolve alkali and carbonate in deionized water to prepare a precipitant solution B, wherein the concentration of alkali in the precipitant solution is 0.1-0.2 mol/L and the concentration of carbonate is 0.25-0.35 mol/L;
• said alkali is NaOH or KOH, and said carbonate is Na2CO3 or K2CO3;
• C. drop equal volumes of solution A and solution B into the reactor at the same time, keep the pH of the solution at 9-11, and stir at 400-600 r/min to obtain a layered double hydroxides (LDHs) suspension;
• age in a 60-80° C. water bath for 12-18 h, wash and centrifuge the LDHs suspension until neutral;
• dry at 50-60° C. for 12-24 h, take it out and grind it to obtain a LDHs powder, whose chemical formula is [M1-x2+Mx3+(OH)2]x+ (An−)x/n·mH2O;
• the axial dimension of the LDHs in the LDHs powder is 20-30 nm;
• D. perform an etching step by adding the LDHs powder into an etching solution so that the LDHs content in the solution is 2.3-2.8 mg/ml;
• etch for 1-2 h, centrifuge and wash the solution until neutral, and dry for 12-24 h at 50-60° C. to obtain a catalyst with defect points;
• said etching solution is KOH or NaOH solution with the concentration of 1-2 mol/L;
• wherein the LDHs prepared in step C is one of CuCoAl-LDHs, CuCoFe-LDHs, ZnCoFe-LDHs and CuZnGa-LDHs.