Cu Facet-Dependent Elementary Surface Reaction Kinetics of CO<sub>2</sub> Hydrogenation to Methanol Catalyzed by ZrO<sub>2</sub>/Cu Inverse Catalysts
Wei Xiong, Jieqiong Ding, Dongdong Wang, Weixin Huang
Abstract
ZrO 2 –Cu-based catalysts are active in catalyzing the hydrogenation of CO 2 to methanol. Herein, we report Cu facet effects on the catalytic performance of ZrO 2 /Cu inverse catalysts in CO 2 hydrogenation to methanol using various Cu nanocrystals with well-defined Cu morphologies and facets. The ZrO 2 –Cu interface is the active site, in which the ZrO 2 –Cu{100} and ZrO 2 –Cu{110} interfaces exhibit similar apparent activation energies of ∼42.6 kJ/mol, smaller than that of the ZrO 2 –Cu{111} interface (∼64.5 kJ/mol). Temporal in situ diffuse reflectance infrared Fourier transform spectroscopy characterization results identify the bridge formate hydrogenation as the rate-determining elementary surface reaction under typical reaction temperatures, whose activation energy is similar at the ZrO 2 –Cu{100} (∼36.3 kJ/mol) and ZrO 2 –Cu{110} (∼40.5 kJ/mol) interfaces and larger at the ZrO 2 –Cu{111} interface (∼54.5 kJ/mol). This fundamental understanding suggests Cu facet engineering as a promising strategy to improve the catalytic performance of ZrO 2 /Cu inverse catalysts for CO 2 hydrogenation to methanol.