Unveiling the Balance between Catalytic Activity and Water Resistance over Co3O4 Catalysts for Propane Oxidation: The Role of Crystal Facet and Oxygen Vacancy

Environmental water inevitably influences the catalytic oxidation of volatile organic compounds (VOCs). Herein, particle-, sheet-, and rod-like Co3O4 (Co3O4-P, Co3O4-S, and Co3O4-R, respectively) were fabricated and the effect of water on propane oxidation was explored. The results showed that Co3O4-P displayed the best catalytic activity under dry conditions, while Co3O4-R presented the best water resistance under humid conditions. A series of correlative characterizations and DFT calculations were adopted to reveal the effect of water at the atomic level. It can be obtained that Co3O4 with the (110) plane promotes the formation of oxygen vacancy and the mobility of surface lattice oxygen, while Co3O4 with the (111) plane has a weaker water adsorption capacity, resulting in the balance effect of catalytic activity and water resistance. The inhibitory effect of water on catalytic activity can be attributed to the competitive adsorption of water that weakens the adsorption of propane and restrains the mobility of surface lattice oxygen. Significantly, this work will be helpful for understanding the design of water-resistant catalysts with defect engineering and crystal facet engineering.