Partial Ni‐Embedded NiO/g‐C3N4 Nanocomposite Utilizing g‐C3N4 as a Sacrificial Support and Intrinsic Reducing Agent for Sustainable Photoelectrochemical Hydrogen Production

Abstract Layered g‐C 3 N 4 holds great potential for photoelectrochemical (PEC) water splitting, but its performance is restricted by significant charge recombination and slow reaction kinetics. To address this, we demonstrate a novel approach to enhance PEC efficiency using a Ni/NiO/g‐C 3 N 4 nanocomposite, synthesized by leveraging g‐C 3 N 4 as both a sacrificial support and an intrinsic reducing agent. Pyrolysis of g‐C 3 N 4 with NiO in air, without external reducing agents, enabled the formation of metallic Ni and NiO within the composite. Comprehensive analyses, including XRD, FTIR, TEM, XPS, PL, and TRPL, confirmed the structural and electronic properties, highlighting improved charge separation and transport. Optimization of the NiO to g‐C 3 N 4 ratio revealed a synergistic effect of Ni and NiO, significantly enhancing PEC water splitting performance. This sustainable and efficient synthesis strategy underscores the dual functionality of g‐C 3 N 4 and advances the development of eco‐friendly catalytic materials.