Hydrothermal Carbon with Abundant Oxygen-Containing Functional Groups for Photocatalytic H2O2 Generation in Water and Seawater
Photocatalytic production of hydrogen peroxide (H2O2) from sustainable biomass-derived carbon catalysts offers a renewable route to valuable chemicals, yet the regulatory role of surface functional groups on reaction kinetics remains underexplored. Here, hydrothermal carbon spheres (CS) rich in oxygen-containing functional groups demonstrated a remarkably high H2O2 production rate of 653 μmol/(g·h) in both pure water and actual seawater, without any sacrificial agent. The catalyst also exhibited outstanding activity in visible-light-driven photocatalytic oxidation of benzylamine to imines, achieving 92% conversion and >99% selectivity. Comprehensive analysis revealed that CS was rich in surface oxygen-containing functional groups, a feature strongly associated with its high photocatalytic efficiency. The observed positive Zeta potential of CS in seawater likely diminished electrostatic repulsion against positively charged intermediates, facilitating their accumulation at the liquid-solid interface. This work proposes a strategic framework for developing metal-free photocatalysts from biomass, offering a sustainable pathway for photocatalytic applications.