Strong Metal–Support Interactions between Nickel and Iron Oxide during CO<sub>2</sub> Hydrogenation
Xiaohan Yuan, Tiancheng Pu, Mengwei Gu, Minghui Zhu, Jing Xu
Abstract
Understanding the interaction of metal with metal oxides is essential for establishing the structure–activity relationship in heterogeneous catalysis. Herein, a series of nickel–iron-based bimetallic catalysts are systematically investigated to unveil the nature of active sites for the CO2 hydrogenation reaction. An environmental-sensitive strong metal–support interaction between Ni nanoparticles and iron oxides is revealed by a series of characterizations, including HR-TEM, H2-TPR, quasi in situ XPS, and time-resolved in situ DRIFTS. Iron oxides migrate and entirely cover the metallic Ni nanoparticles during the reaction, yielding a more active core–shell-type structure with much-improved reducibility. Such a reconstruction process is also indirectly monitored in a time-resolved manner by in situ DRIFTS and confirmed to complete within 30 min of the reaction.