Application Of Co-based Catalysts In Reverse Water Gas Shift Reaction

With the rapid development of society and economy,the problems brought about by the development are becoming more and more obvious.The greenhouse effect is a more important issue.CO₂ is an important contributor to the greenhouse effect.Therefore,CO₂ conversion is of great concern,the reaction is one of the most promising applications.At present,most of the catalysts have high thermal stability and poor selectivity.In this paper,Co/CaCO₃ and Co-CeO₂ catalysts were synthesized by different methods.It was expected to develop high performance cobalt-based water reversal gas evolution catalysts and related research.The main contents and results are as follows:1?The Co / CaCO₃ catalyst was prepared by impregnation with the tail of the fish.The effects of cobalt content on the structure and properties of the catalysts were investigated.The results show that,the catalyst with different cobalt content had different composition.When the cobalt content was less than 30%,the cobalt in the catalyst mainly existed in the form of Ca2Co2O5;large particles of Co3O4 appeared when the cobalt content reached 50%.The selectivity of 30% Co/CaCO₃ catalyst was 100% at the reaction temperature of 700?,the CO₂ conversion rate was 38% and the catalytic performance was stable in 30 h.2?The effect of cobalt content on the structure and properties of the catalyst was studied by the method of hydrothermal synthesis of SBA-16 as template and hard template method.The effects of cobalt content on the structure and properties of the catalysts were investigated.The cobalt and cerium species in the catalyst are in the form of Co3O4 and CeO₂,respectively.It was found that the catalyst prepared by hard template method had higher specific surface area and pore size and higher dispersion of cobalt and stronger interaction between cobalt and cerium than that of coprecipitation method,and thus had higher RWGS activity and selectivity.3?The Co-CeO₂ catalyst prepared by the silica sol method was used for the RWGS reaction.The results show that the catalyst prepared by silica sol method has higher specific surface area and pore size and higher dispersion of cobalt and stronger interaction between cobalt and cerium than that of coprecipitation method,and thus has higher RWGS activity and selectivity.Compared with the impregnation method,the catalyst prepared by the silica sol method has better cobalt dispersion,and the cobalt cerium interaction is enhanced,so it has higher RWGS activity and selectivity.In addition,the specific surface area is related to the amount of silica sol added,and the addition of Zr also has a significant effect on the surface area,the Co-CeO₂ catalyst prepared by the silica sol method can embed the Co3O4 in the CeO₂ pore wall with high dispersion and thus has higher thermal stability.