Preparation And Modification Nickel-based Zirconium Oxide Catalyst For Methanation Reaction

Combustion of fossil fuel,along with the emission of large amounts of carbon dioxide?CO₂?,is the main cause of global warming,leading to a series of ecological environment problems.How to capture and utilize CO₂ has absorbed the concerns and debates of many scholars all over the world.As a important chemical materials,CO₂ can be used for hydrogenation reaction,synthetic carbonic ester and urea.As the main components of substitute natural gas,methane?CH₄?occupies a particularly critical position in the national product.It is of great significance to convert CO₂ into CH₄.Therefore,CO₂ hydrogenation methanation reaction has great prospects for development.Renewable energy such as solar or wind power used for electrolytic hydrogen production,and further to synthetic CH₄ by power-to-gas?PtG?technology,is the main utilization way of CO₂ chemical.In recent years,a several of demonstration PtG projects have been built in Germany,Japan and American.China should vigorously develop new energy power generation technology,CO₂ capture technology,and significantly decrease the cost of PtG technology,which could effectively reduce carbon dioxide emissions and relieve the crisis of natural gas shortage.This paper firstly synthesize three different crystalline phases zirconia?ZrO₂?successfully,the prepared zirconia was then impregnated to obtain Ni/ZrO₂ catalysts.Subsequently,we investigated the performance of CO₂ methanation process by adding Re and W,the effect of ZrO₂ crystal phase and promoter adding for CO₂ methanation has been analyzed.The main research contents has summarized as followed:?1?ZrO₂ crystal Ni has a significant impact to Ni sizes,Ni/t-ZrO₂ has smallest particle size of Ni?17.18 nm?from Scherrer's equation.?2?Relatively more alkaline site and oxygen vacancies in Ni/t-ZrO₂ catalyst surface has stronger adsorption of CO₂ to form monodentate and bidentate carbonates which could easily decompose into CO₂.?3?Different loadings?1-9 wt%?of Ni/t-ZrO₂ catalysts has prepared,among these catalysts,7Ni/t-ZrO₂ catalysts shows highest activity,reaching monolayer dispersion threshold value of metal Ni on t-ZrO₂ surface?0.388 g/g?.?4?CO₂ conversion increased to 80%,CH₄ selectivity reached 85% after adding 4wt% Re or W respectively at 500°C,the promoters increased the number of oxygen vacancies and then improve the methanation performance.