Enhanced Methanol Synthesis over Self‐Limited ZnOx Overlayers on Cu Nanoparticles Formed via Gas‐Phase Migration Route

Supported metal catalysts are widely used for chemical conversion, in which construction of high density metal‐oxide or oxide‐metal interface is an important means to improve their reaction performance. Here, Cu@ZnOx encapsulation structure has been in situ constructed through gas‐phase migration of Zn species from ZnO particles onto surface of Cu nanoparticles under CO2 hydrogenation atmosphere at 450 °C. The gas‐phase deposition of Zn species onto the Cu surface and growth of ZnOx overlayer is self‐limited under the high temperature and redox gas (CO2/H2) conditions. Accordingly, high density ZnOx‐Cu interface sites can be effectively tailored to have an enhanced activity in CO2 hydrogenation to methanol. This work reveals a new route for the construction of active oxide‐metal interface and classic strong metal‐support interaction state through gas‐phase migration of support species induced by high temperature redox reaction atmosphere. Zn species evaporated from ZnO particles can migrate and deposit onto Cu surface to form Zn oxide (ZnOx) encapsulation layers i.e., strong metal‐support interaction state under CO2 hydrogenation atmosphere at 450 °C in ZnO||Cu catalyst. The gas‐phase deposition of Zn species and growth of ZnOx overlayer on Cu surface is self‐limited, which constructs an optimal number of ZnOx‐Cu interface sites to have enhanced methanol synthesis activity.