Ni–Zn Dual Sites Switch the CO<sub>2</sub> Hydrogenation Selectivity via Tuning of the d-Band Center
Shuangxi Lin, Qiang Wang, Maoshuai Li, Ziwen Hao, Yutong Pan, Xiaoyu Han, Xiao Chang, Shouying Huang, Zhenhua Li, Xinbin Ma
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.