Fabrication of Zr–Ce Oxide Solid Solution Surrounded Cu-Based Catalyst Assisted by a Microliquid Film Reactor for Efficient CO₂ Hydrogenation to Produce Methanol

Abstract

Currently, supported copper-based catalysts have been regarded as one of the most promising catalysts for catalyzing the hydrogenation of CO2 to synthesize methanol, due to their good selectivity to methanol. However, the low dispersion of copper species and weak interactions between metal and the support easily led to the low catalytic activity and sintering of copper particles (i.e., deactivation). In this work, we fabricated a Zr–Ce oxide solid solution (ZrCeO2) surrounded Cu-based catalyst to improve the dispersion of Cu nanoparticles (NPs) by a facile microliquid film-assisted coprecipitation (Cf) method. Compared to those obtained by traditional coprecipitation and impregnation, more highly dispersed copper NPs were formed by the Cf method. Moreover, Cu NPs were surrounded by small ZrCeO2 particles, thereby forming strong metal–support interactions and thus abundant metal–support interfaces. Catalytic reaction results demonstrated that as-formed Cu-based catalyst by the Cf approach (Cu-Cf) performed higher CO2 conversion and methanol yield, compared with the other two Cu-based comparison ones. It was revealed that besides the formation of the highly dispersed active copper sites, the existence of favorable multiple interfacial active sites in the Cu-Cf catalyst, i.e., Cu+–O–M (M = Ce, Zr) and defective Ce3+–Ov–Zr4+ structures (Ov: oxygen vacancy), could accelerate the transformation of formate intermediate and further improve the formation of methanol. This paper provides a feasible strategy for constructing robust copper-based catalysts through regulating multiple interfacial structures for the hydrogenation of CO2 to produce methanol.

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