Multiscale Catalyst Engineering for Stable, Selective, and Carbon-Neutral Industrial Hydrogen Peroxide Electrosynthesis

Abstract

The electrocatalytic two-electron oxygen reduction reaction (2e⁻ ORR) has emerged as a pivotal strategy for sustainable hydrogen peroxide (H₂O₂) synthesis, offering a carbon-neutral alternative to the energy-intensive anthraquinone process. This review critically synthesizes recent breakthroughs in catalyst design, mechanistic understanding, and system integration to address the persistent selectivity–stability trade-off. Key advances include atomic-level engineering of electronic modulation and surface functionalization and hydrophobicity control, which achieve > 95% H₂O₂ selectivity by precisely tuning *OOH adsorption energy and suppressing 4e⁻ pathways. Hierarchical architectures, such as flow-through electrodes and catalytic membranes, extend operational stability beyond 500 h at industrial current densities (> 200 mA cm⁻²) through confinement effects and interfacial engineering. Emerging operando characterization techniques coupled with machine learning-accelerated simulations now enable dynamic mapping of active-site evolution and degradation mechanisms. System-level innovations integrating renewable energy input and circular carbon strategies demonstrate pilot-scale feasibility for net-negative emission H₂O₂ production. However, persistent challenges in scalability, long-term catalyst durability under fluctuating loads, and techno-economic gaps between laboratory and industrial implementations require urgent attention. We propose a multidisciplinary roadmap combining materials genome initiatives, modular reactor design, and policy-driven lifecycle assessment frameworks to accelerate the deployment of 2e⁻ ORR systems. This work provides actionable guidance for advancing carbon-neutral chemical manufacturing through electrochemical routes aligned with global net-zero goals.