Preparation Of CO₂ Methanation Catalysts With High Specific Surface Area By Solution Combustion Method

Today,the greenhouse effect is affect our daily life from different directions,the extensive use of energy is the main source of greenhouse gases,the transportation is one of the key areas of energy consumption and greenhouse gas emissions,with the increase of the next few years researchers and the liquidity,greenhouse gas emissions are only grow.The safety and cost control of hydrogen energy storage and transportation are also major challenges in today’s society.The CO₂ methanation can convert carbon dioxide and hydrogen into methane,which is easier to store.It can fully reuse carbon dioxide and solve the problem of high cost of hydrogen energy storage and transportation.Nickel-based catalysts are widely used in the methanation of carbon dioxide,but the agglomeration of nickel particles tends to occur when the nickel content is high,which affects the activity of CO₂ methanation.Solution combustion method has a series of advantages such as simple preparation device,low cost,fast reaction rate and relatively low preheating temperature,but it is prone to the problem of relatively low specific surface area of catalyst in the preparation of catalyst.In order to study catalysts with high specific surface area and high activity,different types of nickel-based catalysts were prepared by salt-assisted solution combustion method and silica-sol assisted solution combustion method,and their physical and chemical structures and catalytic effects on the reaction were investigated.The main contents are as follows:50%Ni-Ce O₂ catalyst was prepared by salt-assisted solution combustion method,that is,a certain amount of Na Cl was added in the process of preparation by ordinary solution combustion method and then cleaned.The mesoporous structure was preserved in the catalyst,and the optimal activity of the catalyst at low temperature was obtained when n（Na Cl）/n（Ni+Ce）=0.5.The CO₂ conversion rate（9.9%）at 250℃is nearly three times that of the catalyst prepared by common solution combustion method.XRD,BET,TPR,TPD and TEM were used to characterize the catalyst to analyze the structure and properties of the catalyst.The catalyst had irregular mesoporous structure.Na Cl reduced the particle size of the catalyst,so that the catalyst also had a large specific surface area in the catalyst with high nickel content.When the Ni content continues to increase and the solution combustion method is assisted by silica sol,the activity and physical and chemical properties of the catalysts are studied when only a small amount of Y₂O₃,Ce O₂,La₂O₃ and Zr O₂ are added into the catalyst.At this time,the catalysts show the structure state of mesoporous reverse load.After that,the five groups of catalysts are characterized differently.Characterization of the result can be analyzed out the addition of metal oxide catalyst in size of the state,catalyst indeed have abundant mesoporous structure at the same time,the interaction between metal and carrier of catalyst reduction temperature,catalysts with high dispersion of nickel surface with large surface defect density to the chemical adsorption of hydrogen makes catalyst activity is significantly increase...