Interfacial hydrogen transfer for heterogeneous catalysis.

The efficient transfer of hydrogen species at interfaces is a crucial yet poorly understood determinant in heterogeneous catalytic systems, involving energy conversion, chemical synthesis and pollution abatement. This interfacial hydrogen transfer (IHT), which shuttles key hydrogen intermediates from their formation sites to reaction sites, often dictates overall catalytic efficiency and selectivity. However, fundamental questions remain related to the driving force and structure-activity relationship in IHT processes, as well as the potential interplay between different IHT pathways in complex systems. This Review details the chemical identity of hydrogen species (H+, H· and Hδ-) to delineate their generation, transfer and catalytic application across different systems. By comparing reaction mechanisms and design principles, we discuss the connection of various IHT pathways, demonstrating how hydrogen migration dictates the activity and selectivity of a wide range of heterogeneous catalytic processes, including hydrogen evolution, hydrogenation and fuel cells. By identifying the challenges and outlining future research avenues, we provide a roadmap for the rational design of next-generation catalysts with precisely controlled hydrogen dynamics.