Advances in gas-solid-liquid triple-phase interface engineering towards efficient oxygen reduction reaction

Oxygen reduction reaction (ORR) as a key electrochemical reaction for the advanced energy storage and conversion technology, is a complex surface-dominated process comprising several indispensable steps of electron transfer, mass diffusion and adsorption/desorption of reactant/products at the gas-solid-liquid triple-phase interface. In the past few years, great processes have been made in regulating the interface micro-environment based on the optimal design of electrode structure and controllable construction of electrocatalysts, resulting in the boosted electro-catalytic performances and the in-depth understanding of the underlying fundamentals of ORR. In this review, the most recent progresses in the triple-phase interface engineering for ORR have been reviewed in a comprehensive manner by emphasizing the issues such as the general design principles of electrode and catalyst, and the extensive ORR mechanism exploration at the triple-phase interface both experimentally and theoretically. This review focuses on the advanced topic of triple-phase interface engineering for efficient ORR, presenting and discussing the most recent advancements. Additionally, it addresses the challenges and offers an in-depth exploration of the prospective future directions in this field. • ORR performance dependent on the triple-phase interface is summarized. • Electrode structure design strategies are listed. • Design principles of the ORR catalysts are presented. • ORR reaction mechanism at the triple-phase interface is outlined.