Interface-driven electronic coupling in carbon-supported electrocatalysts for electrochemical energy conversion

Electrochemical energy conversion technologies, including fuel cells, metal–air batteries, and water electrolysers, are indispensable for achieving a sustainable energy future. Nevertheless, their widespread deployment is hindered by the sluggish kinetics of key electrochemical reactions, particularly the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). Although carbon-supported electrocatalysts have emerged as promising alternatives to noble-metal catalysts because of their high electrical conductivity, structural versatility, chemical stability, and cost-effectiveness, growing evidence indicates that their catalytic performance is governed not only by the intrinsic properties of the active components but, more importantly, by interface-driven electronic coupling between the catalyst and carbon support. These interfacial interactions regulate charge redistribution, orbital hybridisation, defect evolution, adsorption energetics, and dynamic surface reconstruction, thereby determining reaction kinetics, catalytic selectivity, and long-term stability. This review critically examines the fundamental mechanisms underlying electronic coupling at catalyst–carbon interfaces and discusses how built-in electric fields, orbital interactions, defect engineering, adsorption-energy optimisation, and operando structural evolution collectively influence electrocatalytic behaviour. Recent advances in interface engineering through carbon architecture design, heteroatom doping, heterostructure construction, and single-atom anchoring are systematically analysed, with particular emphasis on graphene, carbon nanotubes, porous carbon, and heteroatom-doped carbon frameworks as electronically tunable supports. Representative metal oxide-, metal sulphide-, and single-atom-based carbon-supported electrocatalysts are further evaluated to establish clear correlations between interfacial electronic structure, adsorption behaviour, and catalytic performance. Finally, the review highlights the remaining challenges associated with dynamic active-site evolution, mechanistic characterisation, catalyst durability, and scalable synthesis, and outlines future strategies for the rational design of next-generation carbon-supported electrocatalysts through precise interface engineering.