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

Abstract

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.

Upgrading Trimethylbenzene to Durene by CO2-Mediated Methylation over Cu-Boosted ZnZrOx Integrated with HZSM-5

“…Simultaneously, a slight amount of single-atom Cu species was partially reduced without aggregation, bringing about an H 2 –TPR signal at 219 °C. , Compared with CuO bulk (Figure S15c), the lower H 2 consumption peaks between 174 and 219 °C observed in CuZZO catalysts indicate that the [Cu–O] n structures are not overly aggregated, in agreement with the result of XRD. In addition, peaks at 668 and 705 °C are attributed to the reduction of ZnO, since ZrO 2 is difficult to reduce to metallic Zr below 800 °C, , but ZnO is reducible at 500–750 °C. − The reduced Cu species significantly lowers the reduction temperature of ZnO, indicating that more active *H species are delivered to Zr sites via ZnO species. To get a better signal-to-noise ratio, we conducted D 2 –TPD instead of H 2 –TPD to investigate the hydrogen adsorption of CuZZO (Figure e).…”