Electrochemical synthesis of H 2 O 2 via the two-electron oxygen reduction reaction (2e − ORR) presents a transformative opportunity for decentralized, on-demand production of this essential chemical, providing a sustainable, carbon-neutral replacement for the energy-intensive anthraquinone method. Although there have been major strides forward in catalyst development and mechanistic insights, a persistent gap remains between laboratory-level performance metrics and the requirements for large-scale industrial deployment. In this review, we begin by providing a detailed overview of the 2e − ORR, covering the reaction mechanism, catalyst tuning, and developments in catalyst performance, noting that different experimental and reporting conditions often prevent a proper comparison of available information from the literature. This is followed by a critical assessment of the energy penalty incurred from the anodic oxygen evolution reaction, and advocacy for incorporating alternative, value-added oxidation reactions as an important strategy to improve the overall process economy and energy efficiency. Lastly, we note that moving from basic electrocatalysis to the practical scale-up of H 2 O 2 production requires an integrated, system-level approach that incorporates reactor design, membrane engineering, and product separation, guided by rigorous techno-economic analysis. Our work thus provides a holistic roadmap to bridge the gap between catalyst-centric research and integrated system engineering, which is vital for practical and sustainable H 2 O 2 electrosynthesis. • This review summarizes recent advances in the integrated design of systems for practical H 2 O 2 electrosynthesis, encompassing catalyst engineering, microenvironment regulation, and alternative anodic reactions. • Techno-economic analysis is positioned as a critical guide for system design, linking energy efficiency, electricity cost, and downstream separation to industrial viability. • Opportunities and challenges in translating laboratory-scale catalysts into economically viable H 2 O 2 production are critically assessed.
Li et al. (Sun,) studied this question.