An Overview on Dynamic Phase Transformation and Surface Reconstruction of Iron Catalysts for Catalytic Hydrogenation of CO_x for Hydrocarbons

Abstract

Catalytic hydrogenation of CO x (CO and CO 2 ) with renewable H 2 represents a feasible practice for carbon capture and utilization and synthesis of chemical commodities, such as olefins, aromatics, and higher alcohols as well as liquid fuels. Direct synthesis via Fischer−Tropsch Synthesis (FTS) is considered as one of the most promising processes. Ironbased catalysts have been recognized as efficient candidates for catalytic hydrogenation of both CO and CO 2 to value-added hydrocarbons due to their superior activities for C−O bond dissociative activation, reverse/water gas shift reaction, and C−C chain growth. The structural complexity and dynamic evolution of iron-based catalysts under CO x -FTS conditions impose challenges on the understanding of the reaction mechanisms, the dynamic structure of active sites and further improvements of the catalytic performance. In this Review, we discussed the recent developments in characterization techniques for identifying the structural evolution of iron-based catalysts under reaction conditions. We also summarized feasible strategies to manipulate the process of the structural change via promoter interfacing, catalyst pretreating protocols, and application of external physical fields. Finally, we concluded the review by identifying current challenges and opportunities for the next generation of CO x catalytic hydrogenation process with an emphasis on the combinatorial contributions from in situ/operando characterizations, chemometrics and machine learning.