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

Abstract

Achieving intimate contact is crucial for the efficiency of a photocatalyst that includes both reduction and oxidation compartments, as it directly influences charge carrier transfer between them. However, traditional metal oxide-based photocatalysts often face intrinsic limitations in integrating these two functional components due to the difficulty in adjusting their surfaces. Herein, protonated polymeric carbon nitride nanosheets (CNNS) with controlled electrostatic property was integrated with NiTiO3 (NTO). Among them, CNNS functions as the hydrogen evolution photocatalyst (HEP), and NTO nanoparticles served as the oxygen evolution photocatalyst (OEP), resulting in a photocatalytic system for OWS. The system exhibits H₂ and O₂ evolution rates of 35.6 and 17.7 μmol·h⁻¹, respectively, and the corresponding apparent quantum yield is 2.7% at an incident wavelength of 365 nm, outperforming those of individual photocatalysts. This study introduces an applicable electrostatic self-assembly strategy for using carbon nitride to construct redox-mediator-free heterojunctions, thereby advancing applications in various fields, particularly the hydrogen evolution reaction via photocatalytic OWS.