Surface Plane Effect of ZnO on the Catalytic Performance of Au/ZnO for the CO Oxidation Reaction

In heterogeneous catalysis, specific surface planes of metals and/or supports have a prominent effect on the catalytic processes, i.e., adsorption, dissociation of reactants, and electron transfer behaviors. In addition, surface planes of oxide supports have a direct impact on the shape and dispersion of metal particles through a metal–support interaction. Herein, we synthesized ZnO nanoplates (p-ZnO) exposing mostly polar surfaces and ZnO nanorods (r-ZnO) exposing non-polar surfaces and used them as supports to prepare Au/ZnO catalysts. Then, the surface plane effect of ZnO was demonstrated by employing the CO oxidation reaction. We found that the activity of Au/p-ZnO is superior to that of Au/r-ZnO, which is due to more O2 activation sites on polar surfaces than on non-polar surfaces. Furthermore, Au can activate both polar and non-polar surfaces of ZnO by creating more oxygen vacancies for O2 activation. This study highlights the effects of different surface planes of oxides in catalytic reactions and provides new insights for the development of highly active metal-oxide catalysts.