Electrostatic Self‐Assembly of NiTiO3 on Carbon Nitride as a Photocatalyst for Visible‐Light‐Driven Overall Water Splitting

Achieving intimate interfacial contact between a hydrogen evolution photocatalyst (HEP) and an oxygen evolution photocatalyst (OEP) is crucial for efficient charge carrier transfer, which in turn enhances overall water splitting (OWS) performance. However, traditional metal oxide–based photocatalysts often possess intrinsic limitations. In this study, carbon nitride (CN) with tunable electrostatic properties is employed to form a heterostructure with metal oxides through self‐assembly. As such, protonated polymeric CN nanosheets functioned as the HEP, while NiTiO 3 nanoparticles served as the OEP, resulting in a photocatalytic system for OWS, exhibiting H 2 and O 2 evolution rates of 35.6 and 17.7 μmol h − 1 , respectively. The corresponding apparent quantum yield is 2.7% at an incident wavelength of 365 nm. These results outperform those of individual photocatalysts. This study introduces a universally applicable electrostatic self‐assembly strategy for using CN to construct redox‐mediator‐free heterojunctions, thereby advancing applications in various fields, particularly the hydrogen evolution reaction via photocatalytic OWS.