Atomic Insights into Catalyst–Substrate Interfaces of Self-Supported Electrodes for Energy Conversion and Fuel Synthesis

Abstract

Recent breakthroughs in electrocatalyst design have advanced key redox reactions for large-scale green hydrogen, carbon-based fuel and ammonia production, while rechargeable metal-ion batteries continue to transform the mobility sector. However, charge and mass transfer limitations hinder the efficiency of several electrocatalysts at high current densities, prompting the growing adoption of self-supported electrodes as a solution. These self-supported flexible electrodes, with catalysts directly grown on metal or nonmetal substrates, provide superior conductivity and extended stability under extreme conditions. This approach lowers overpotential, increases current density and electrochemically active surface area (ECSA), and enhances the intrinsic activity through improved turnover frequency (TOF), mass activity and specific activity. This perspective explores the atomic-level electronic structure at catalyst–substrate interfaces, with a focus on orbital interactions that govern reaction pathways and active sites in the anchored electrocatalysts. It also explores the fabrication methods and structural variations of self-supported electrodes in key electrochemical processes, including oxygen evolution reaction (OER), hydrogen evolution reaction (HER), metal–air batteries, CO₂ reduction reaction (CRR), nitrogen reduction reaction (NRR), nitrate reduction reaction (NO₃RR), and electrochemical urea synthesis. Alongside a market survey and overview of existing self-supported systems, it also addresses catalyst–substrate interfacial challenges and experimental methodologies critical to advancing this field.