Atomically Dispersed Zn-Stabilized Ni^δ+ Enabling Tunable Selectivity for CO₂ 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/ZrO₂ for CO₂ hydrogenation. In contrast to Ni/ZrO₂ , the selectivity of NiZn/ZrO₂ is observed to shift from CH₄ to CO. A series of structural characterization results reveals that Zn is atomically dispersed in the NiO and ZrO₂ phases as NiZnO_x and ZnZrO_x , respectively during CO₂ 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/ZrO₂ and bring new insight into the rational design of more efficient heterogeneous catalysts.