Atomically Dispersed Zn-Stabilized Ni δ+ Enabling Tunable Selectivity for CO 2 Hydrogenation.

For a heterogeneous catalytic process, the performance of catalysts could be improved by modifying the active metal with a second element. Determining the enhanced mechanism of the second element is essential to the rational design of catalysts. In this work, Zn was introduced as a second element into Ni/ZrO 2 for CO 2 hydrogenation. In contrast to Ni/ZrO 2 , the selectivity of NiZn/ZrO 2 is observed to shift from CH 4 to CO. A series of structural characterization results reveals that Zn is atomically dispersed in the NiO and ZrO 2 phases as NiZnO x and ZnZrO x , respectively during CO 2 hydrogenation, stabilizing a higher valence state of Ni (Ni δ+ ) under a hydrogenation atmosphere over Ni-O-Zn site and thus promoting the generation of CO. These findings shed light on the O-mediated bimetallic effect of NiZn/ZrO 2 and bring new insight into the rational design of more efficient heterogeneous catalysts.