Recent achievements on the modification of microenvironment for fuel cell catalysis

Hydrogen fuel cells with high energy conversion efficiency and zero carbon emissions play a critical role in addressing energy crises and environmental pollution, when the hydrogen is derived from renewable energy-powered water electrolysis. The core of the reaction lies in the catalytic reaction interface. At this interface, the complex interactions among catalysts, aqueous environments, ion species, and ionomers directly determine the efficiency of the catalytic reaction. This review systematically summarized four key interfacial influencing factors, including adsorption behavior of catalysts, interfacial water dynamics, ion modification, and ionomer-electrode interactions. It provided an in-depth summary of key regulation strategies such as catalyst engineering, interfacial water structure optimization, ionic group functionalization, and interface reinforcement. Furthermore, future development directions are proposed, focusing on in-situ characterization, multiphase interface engineering, durability enhancement of non-precious metal catalysts, and machine learning-driven multiscale modeling, aiming to establish fuel cells as a cornerstone of sustainable energy systems.