Atomically Dispersed Zn‐Stabilized Niδ+ Enabling Tunable Selectivity for CO2 Hydrogenation

• Published in: ChemSusChem Vol. 15; no. 7; pp. e202102439 - n/a
• Main Authors: Wang, Yaning, Feng, Kai, Tian, Jiaming, Zhang, Jiajun, Zhao, Baohuai, Luo, Kai Hong, Yan, Binhang
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 07.04.2022
• Subjects: bimetallic effects; Bimetals; Carbon dioxide; Catalysts; CO2 valorization; Dispersion; heterogeneous catalysis; Hydrogenation; Selectivity; single-atom catalysis; Structural analysis; Valence; Zirconium dioxide
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.202102439

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 NiZnOx and ZnZrOx, respectively during CO2 hydrogenation, stabilizing a higher valence state of Ni (Niδ+) 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. Positively stabilized: For CO2 hydrogenation over NiZn/ZrO2 catalysts, Zn is atomically dispersed in NiO and ZrO2 phases as NiZnOx and ZnZrOx, respectively. The formed Ni−O−Zn sites enhance the bonding strength of Ni to the ligand O, stabilizing Niδ+ under reducing atmosphere. The Niδ+ species weaken the adsorption and hydrogenation capacity of adsorbed CO and promote the reverse water gas shift reaction.