用于逆水煤气变换的尖晶石催化剂研究进展OA

The synthesis of high-value-added carbon compounds via CO2 hydrogenation is recognized as a critical pathway for achieving carbon resource recycling,in which the reverse water gas shift(RWGS)reaction serves as an essential intermediate step,playing a significant role in promoting the deep utilization of CO2 resources.Thermodynamic analysis indicates that high temperatures are favorable for the RWGS reaction,whereas high-temperature imposes stringent requirements on catalyst stability.In recent years,spinel catalysts have shown promising potential in the RWGS reaction due to their high thermal stability,tunable active sites and simple preparation processes.The research progress on spinel catalysts(Cu-based and other metal spinel catalysts)for RWGS reaction was summarized.The structure-activity relationships of spinel catalysts were analyzed,mainly including the influence mechanisms of metal cations,surface oxygen vacancies and basic sites on catalytic behaviors.The RWGS reaction mechanisms were proposed,and the key issues that urgently need to be addressed in this field were discussed.It is demonstrated that the activation of H2 and CO2 is mainly facilitated by active metals and oxygen vacancies.CO2 adsorption and activation are also promoted by basic sites.In addition,the spinel crystal structure exhibits preference and directional regulation for CO2 and CO adsorption.The RWGS reaction mechanisms catalyzed by spinel catalysts are redox mechanism and the associative mechanism.Cu-Al spinel catalysts mainly follow the associative mechanism,while other spinel catalysts such as AFe2O4(A=Ni,Cu or Zn)and ZnCr2O4 spinel catalysts follow the redox mechanism.