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The hydrogen peroxide (H₂O₂) generation via the electrochemical oxygen reduction reaction (ORR) under ambient conditions is emerging as an alternative and green strategy to the traditional energy‐intensive anthraquinone process and unsafe direct synthesis using H₂and O₂. It enables on‐site and decentralized H₂O₂production using air and renewable electricity for various applications. Currently, atomically dispersed single metal site catalysts have emerged as the most promising platinum group metal (PGM)‐free electrocatalysts for the ORR. Further tuning their central metal sites, coordination environments, and local structures can be highly active and selective for H₂O₂production via the 2e⁻ORR. Herein, recent methodologies and achievements on developing single metal site catalysts for selective O₂to H₂O₂reduction are summarized. Combined with theoretical computation and advanced characterization, a structure–property correlation to guide rational catalyst design with a favorable 2e⁻ORR process is aimed to provide. Due to the oxidative nature of H₂O₂and the derived free radicals, catalyst stability and effective solutions to improve catalyst tolerance to H₂O₂are emphasized. Transferring intrinsic catalyst properties to electrode performance for viable applications always remains a grand challenge. The key performance metrics and knowledge during the electrolyzer development are, therefore, highlighted.

Insufficient stability of current carbon supported Pt and Pt alloy catalysts is a significant barrier for proton‐exchange membrane fuel cells (PEMFCs). As a primary degradation cause to trigger Pt nanoparticle migration, dissolution, and aggregation, carbon corrosion remains a significant challenge. Compared with enhancing Pt and PtM alloy particle stability, improving support stability is rather challenging due to carbon's thermodynamic instability under fuel cell operation. In recent years, significant efforts have been made to develop highly durable carbon‐based supports concerning innovative nanostructure design and synthesis along with mechanistic understanding. This review critically discusses recent progress in developing carbon‐based materials for Pt catalysts and provides synthesis–structure–performance correlations to elucidate underlying stability enhancement mechanisms. The mechanisms and impacts of carbon support degradation on Pt catalyst performance are first discussed. The general strategies are summarized to tailor the carbon structures and strengthen the metal–support interactions, followed by discussions on how these designs lead to enhanced support stability. Based on current experimental and theoretical studies, the critical features of carbon supports are analyzed concerning their impacts on the performance and durability of Pt catalysts in fuel cells. Finally, the perspectives are shared on future directions to develop advanced carbon materials with favorable morphologies and nanostructures to increase Pt utilization, strengthen metal‐support interactions, facilitate mass/charge transfer, and enhance corrosion resistance.