Insight into the synergistic effect of oxygen vacancy defects and intimate interfaces in Ni/NiTiO3 for full solar spectrum-driven H2O2 production

The low utilization of solar energy and rapid recombination of photogenerated carriers severely restrict the development of photocatalytic H 2 O 2 production. In this study, a Ni/NiTiO 3 heterojunction (Ni/NTO) with an atomically shared heterointerface is synthesized via an in-situ reduction strategy. The constructed Ni/NTO heterojunction possesses an intimate interface originating from the shared Ni atoms between metallic Ni nanoparticles and NiTiO 3 nanorods (NTO), effectively facilitating interfacial charge transfer and separation between the two components. Additionally, the localized surface plasmon resonance (LSPR) effect induced by oxygen vacancy defects endows the Ni/NTO heterojunction with enhanced near-infrared (NIR) light-harvesting capability and substantial photothermal conversion efficiency. The synergistic effect between oxygen vacancy defects and the strongly coupled interface with shared Ni atoms significantly enhances solar energy utilization efficiency and photogenerated charge carrier separation efficiency of Ni/NTO heterojunction. The Ni/NTO heterojunction exhibits excellent photocatalytic H 2 O 2 production performance, achieving an H 2 O 2 generation rate of 10608 µM/g/h, which is approximately 55 times higher than pristine NTO. Notably, under NIR light (λ > 800 nm) irradiation, a H 2 O 2 production rate of 4022 µM/g/h is achieved. This work is anticipated to provide valuable guidance for the rational design of high-efficiency full-spectrum-responsive heterojunction photocatalysts through coupling interface and defect engineering.