Photocatalytic Overall Water Splitting with a Solar-to-Hydrogen Conversion Efficiency Exceeding 2 % through Halide Perovskite

Photocatalytic water splitting using semiconductors is a promising approach for converting solar energy to clean energy. However, challenges such as sluggish water oxidation kinetics and limited light absorption of photocatalyst cause low solar-to-hydrogen conversion efficiency (STH). Herein, we develop a photocatalytic overall water splitting system using I-3(-)/I- as the shuttle redox couple to bridge the H-2-producing half-reaction with the O-2-producing half-reaction. The system uses the halide perovskite of benzylammonium lead iodide (PMA(2)PbI(4), PMA=C6H5CH2NH2) loaded with MoS2 (PMA(2)PbI(4)/MoS2) as the H-2 evolution photocatalyst, and the RuOx-loaded WO3 (WO3/RuOx) as the O-2 evolution photocatalyst, achieving a H-2/O-2 production in stoichiometric ratio with an excellent STH of 2.07 %. This work provides a detour route for photocatalytic water splitting with the help of I-3(-)/I- shuttle redox couple in the halide perovskite HI splitting system and enlightens one to integrate and utilize multi catalytic strategies for solar-driven water splitting.