Interfacial Redox Decoupling via Amphiphilic Carbon Dots for Highly Efficient Biphasic Photocatalytic H2O2 Production and Selective Benzyl Alcohol Oxidation

Photocatalytic hydrogen peroxide (H2O2) production from water and molecular oxygen offers a sustainable alternative to the energy-intensive anthraquinone process; however, its practical advancement is limited by inefficient charge utilization, poor selectivity, product instability, and challenging separation. Herein, we report a quasi-homogeneous phase-transfer photocatalytic system enabled by rhodamine B-derived amphiphilic carbon dots that enables interfacial redox decoupling for high-efficiency H2O2 photosynthesis. The as-prepared carbon dots serve a trifunctional role as visible-light harvesters, interfacial stabilizers, and redox catalysts, facilitating the formation of a light-responsive water/benzyl alcohol emulsion. This biphasic architecture maximizes interfacial charge carrier flux while ensuring spontaneous phase separation postirradiation. In this configuration, the two-electron oxygen reduction reaction is localized within the aqueous phase, while the photogenerated holes drive the selective oxidation of benzyl alcohol to value-added benzaldehyde in the organic phase. Consequently, an exceptional H2O2 production rate of 13 250 μmol g–1 h–1 is achieved, accompanied by a benzyl alcohol conversion of 83.7% and a benzaldehyde yield of 82.6%. This strategy not only suppresses H2O2 decomposition through spatial segregation but also enables in situ product isolation and facile catalyst recycling. This work establishes interfacial phase-transfer photocatalysis as a robust and versatile platform for integrating solar-to-chemical energy conversion with selective organic transformations.