Preparation Of Highly Dispersed Ni-based Catalysts Based On Surface Modification And Its Effect On CO₂ Methanation Performanc

The resource utilization of carbon dioxide（CO2）can reduce carbon emissions and effectively control environmental climate change.Among them,CO2 methanation can not only reduce CO2 emissions,but also obtain a high value-added energy product-methane（CH4）.Due to the influence of kinetics on CO2 methanation reaction at low temperatures,it is urgent to develop catalysts with low temperature efficiency.Ni based catalysts have excellent low-temperature activity and low synthesis cost,which are suitable for CO2 methanation reaction.However,Ni active site is easy to be sintered at high temperature,which affects the decomposition of H2 and the generation rate of CH4.It is found that this problem can be solved by improving the dispersity of the metal Ni active site and the redox performance of the catalyst.Through in-depth research on the amino functionalization of the support and the modification of the promoter of the catalyst,it is found that the surface modification of the catalyst can improve the dispersion of the metal Ni active site,the surface alkalinity of the catalyst,the redox performance and the low-temperature activity of the CO2 methanation reaction.The main research contents are as follows:（1）Selecting fibrous mesoporous silica microspheres（KCC-1）and commercial Si O2 as supports,the effects of different support materials on CO2 methanation reaction were studied.Subsequently,KCC-1 was surface modified to investigate the effect of functionalized Ni based catalysts on CO2 methanation reaction.The research results indicate that the surface modification of the support improves the dispersibility of metal Ni active site,the surface alkalinity of the catalyst,and the low-temperature activity of the catalytic reaction.（2）Select rare metal oxides（Pr O₂,Sm₂O₃,Ce O₂,and La₂O₃）as promoters for Ni-based catalysts to study the effect of the addition of promoters on the structural performance of the catalyst and the performance of CO₂ methanation reaction.The results show that the addition of rare earth metal oxides can improve the oxygen vacancies on the catalyst surface,the dispersion of active site and the low-temperature activity of the CO₂ methanation reaction.（3）Select different support materials（Si O₂,Al₂O₃,ZSM-5,MCM-41,and SBA-15）for functionalization modification.The results indicate that the surface modified supports can improve the redox and surface alkalinity of the catalyst,and promote the low-temperature activity of CO₂ methanation reaction.This further proves the universal applicability of amino functionalization for surface modification of different support materials.