Ni–Zn Dual Sites Switch the CO2 Hydrogenation Selectivity via Tuning of the d-Band Center

Abstract

Controlling the selectivity of CO2 hydrogenation by catalysis is a fundamental challenge. This study examines the interrelation between active sites and reaction pathways in Ni-catalyzed CO2 hydrogenation. The alloying of Ni with Zn to charged (Niσ––Znσ+) active sites modifies the electronic structure and d-band center, weakens the interaction with CO/H2, and preferentially catalyzes the reverse water gas shift to CO with the thermodynamically favored methanation pathway switched off. The charged dual sites can stabilize the activated CO2 species in a η2(C, O) bridge configuration, directly dissociate the C═O bond to *CO, and promote CO desorption. The mechanistic investigation has elucidated the reaction pathways in the Ni-catalyzed CO2 hydrogenation and identified the crucial intermediates that impacted the product selectivity, which can provide a theoretical guide for the Ni-based catalyst design.