Integrated p-n/Schottky junctions for efficient photocatalytic hydrogen evolution upon Cu@TiO2-Cu2O ternary hybrids with steering charge transfer

Solar-driven photocatalytic H 2 evolution could tackle the issue of fossil fuels-triggered greenhouse gas emission with sustainable clean energy. However, splitting water into hydrogen with high performance by a single semiconductor is challenging because of the poor charge separation efficiency. Herein, a novel ternary Cu@TiO 2 -Cu 2 O hybrid photocatalyst with multiple charge transfer channels has been designed for efficient solar-to-hydrogen evolution. Indeed, the ternary Cu@TiO 2 -Cu 2 O hybrid by coupling Cu@TiO 2 with Cu 2 O nanoparticles shows highly-efficient photocatalytic hydrogen generation with rate of 12000.6 μmol·g −1 ·h −1 , which is 4.4, 2.1, and 1.9 times higher than the pure TiO 2 (2728.8 μmol·g −1 ·h −1 ), binary Cu@TiO 2 (5595.5 μmol·g −1 ·h −1 ), and TiO 2 -Cu 2 O (6076.8 μmol·g −1 ·h −1 ) composite, respectively. In such a Cu@TiO 2 -Cu 2 O hybrid, the formed internal electric field in the TiO 2 -Cu 2 O p-n junction allows the electrons in Cu 2 O to migrate to TiO 2 , while the electrons in the CB of TiO 2 could flow into Cu via the Schottky junction at the Cu@TiO 2 interface. In this regard, a multiple charge transfer is achieved between the Cu@TiO 2 and Cu 2 O, which facilitates promoted charge separation and results in the construction of electron-accumulated center (Cu) and hole-enriched surface (Cu 2 O). This p-n/Schottky junctions with steered charge transfer assists the hydrogen production upon the Cu@TiO 2 -Cu 2 O ternary photocatalyst.