Unraveling the role of basic sites in the hydrogenation of CO2 to formic acid over Ni-based catalysts

Basic sites profoundly affect the mode and strength of CO 2 adsorption in the hydrogenation of CO 2 to formic acid (FA), however, the mechanism by which the quantities and strength of basic sites affect the reaction process is not yet clear. Herein, a Ni/Mg a AlO x catalyst has been developed and the basic sites of the catalyst can be modulated by simply altering the Mg/Al ratio. Through a series of characterizations and experiments, it was observed that weak and medium basic sites synergistically catalyzed the hydrogenation of CO 2 to formic acid, and a reasonable number of weak basic sites can improve reaction performance when a sufficient number of medium basic sites guarantee the fundamental catalytic activity. Moreover, the number and distribution of basic sites are also tightly related to metal-support interactions. This strategy provides theoretical guidance and a feasible scheme for optimizing the performance of non-precious metal heterogeneous catalysts.