Parallel-Driven Interlocked Catalytic System for Efficient Suppression of Reverse Reactions in Photocatalytic Water Splitting

One of the key challenges in particulate-based photocatalytic water splitting is the occurrence of reverse reactions, reducing the overall catalytic efficiency. Inspired by natural photosynthesis, we introduce a parallel-driven interlocked catalytic system (PICS), which integrates homogeneous and heterogeneous reactions. In PICS, the transport subsystem (TS) and reaction subsystem (RS) are macroscopically interlocked to enable parallel driving by incident light, enhancing synergistic photoexcitation between H₃PO₄-treated g-C₃N₄ (PCN) and [Ru(bpy)₃]²⁺ ([Ru²⁺]). Within the RS, a microscopically functional interlock is established between PCN and the unidirectional redox cycle ([Ru]-cycle), facilitated by electrostatic attraction, π-π stacking interactions, and the photothermal effect. This arrangement ensures the separate completion of hydrogen and oxygen evolution reactions, effectively mitigating reverse reactions. The optimized PICS demonstrates improved activity, producing hydrogen and oxygen at rates of 0.621 and 0.312 mmol·m^-2·h^-1 over 18 h with an apparent quantum yield of 1.92% at 405 nm and a solar-to-hydrogen efficiency of 0.059%.