Interfacial wettability and mass transfer characterizations for gas-liquid-solid triple-phase catalysis

Heterogeneous catalysis is inseparable from interfacial mass transfer and chemical reaction processes determined by the structure and microenvironment. Different from high-temperature thermochemical processes, photo- and electrocatalysis operated at mild conditions often involve both gas and liquid phases, making it important but challenging to characterize the reaction process typically occurring at the gas-liquid-solid interface. Herein, we review the scope, feasibility, and limitation of ten types of currently available technologies used to characterize interfacial wettability and mass transfer properties of various triple-phase catalytic reactions. The review summarizes techniques from macroscopic contact angle measurement to microscopic environment electron microscopy for investigating the wettability-controlled structure of triple-phase interfaces. Experimental and computational methods in revealing the interfacial mass transfer process have also been systematically discussed, followed by a perspective on the opportunities and challenges of advanced characterization methods to help understand the fundamental reaction mechanism of triple-phase catalysis.