Nanoscale reduction-site-selective oxygen regulation for promoting hydrogen peroxide production

Solar-driven H₂O₂ production is a promising sustainable technology, yet its efficiency is hindered by a fundamental conflict. While the oxygen reduction reaction requires a high O₂ concentration, this very condition suppresses the water oxidation half-reaction. This trade-off is intrinsic to conventional photocatalysts, where both reaction centers are integrated on a single nanoparticle. Here we present a nano-assembly strategy that addresses this trade-off. We use a faceted photocatalyst to spatially segregate the sites for water oxidation and oxygen reduction. The reduction sites are selectively functionalized with zeolite nanovessels as O₂ traps. This design enhances the local O₂ concentration where needed, without suppressing the competing oxidation reaction. The optimized system exhibits a 3.1-fold increase in H₂O₂ production, achieving a solar-to-chemical efficiency of 1.05% and an apparent quantum yield of 15.9% at 420 nm. Successful operation in an outdoor panel reactor demonstrates the approach's scalability. This study underscores the role of local mass regulation in enhancing H₂O₂ generation and provides a strategic framework for designing photocatalytic systems.