Cu2(OH)2CO3 clusters: Novel noble-metal-free cocatalysts for efficient photocatalytic hydrogen production from water splitting

Photocatalytic hydrogen evolution is a potential route for converting inexhaustible solar energy into available clean chemical energy. Herein, highly efficient and stable Cu2(OH)2CO3/TiO2 photocatalysts for hydrogen generation are prepared by incorporating Cu2(OH)2CO3 clusters onto the surface of TiO2 through a facile precipitation method. The obtained Cu2(OH)2CO3/TiO2 photocatalyst with optimal Cu2(OH)2CO3 content of 0.5 mol% shows an outstanding photocatalytic H2-production rate of 6713 μmol h−1 g−1 (with apparent quantum efficiency of 15.4% at 365 nm), which is comparable to the excellent Pt/TiO2 photocatalyst and more efficient than other copper specie modified TiO2 photocatalyst. The formation of Cu2(OH)2CO3/Cu+/Cu0 clusters essentially contribute to the enhanced H2-production activity by reducing the over-potential of water reduction and promoting the transfer of photogenerated electrons from the conduction band of TiO2 to the Cu2(OH)2CO3/Cu+/Cu0 clusters. A high stability of the Cu2(OH)2CO3/TiO2 photocatalyst is achieved due to the re-oxidation process of Cu+/Cu0 to Cu2(OH)2CO3 and structure confinement of Cu2(OH)2CO3 clusters in the mesopores of TiO2. This work brings in new insight in developing low-cost noble-metal-free photocatalytic system for solar-to-fuel conversion.