Integrated p-n/Schottky junctions for efficient photocatalytic hydrogen evolution upon Cu@TiO 2 -Cu 2 O 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.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2022 Elsevier Inc. All rights reserved.)