Vapor deposition assisted in-situ construction of graphitic carbon nitride homojunction capable of enhanced visible-light-driven hydrogen generation

Abstract

Graphitic carbon nitride (g-C₃N₄) is an attractive photocatalyst due to its optimal bandgap (~2.7 eV), high chemical stability, and environmentally friendly synthesis process. However, the low photogenerated charge carrier separation efficiency and specific surface area significantly limit the hydrogen evolution rate. In this study, a novel g-C₃N₄ homojunction material with controllable morphology was successfully fabricated via a simple and efficient vapor deposition method, which could significantly improve the photocatalytic performance without the introduction of metal elements. Under visible light irradiation, this material demonstrated exceptional photocatalytic hydrogen evolution performance, achieving a hydrogen production rate of 334 μmol g⁻¹ h⁻¹, approximately 24 times higher than that of conventional bulk g-C₃N₄. This remarkable enhancement in performance can be attributed to the synergistic effects of several factors, including a significant increase in specific surface area, expanded visible-light absorption range, efficient separation and migration of photogenerated charge carriers, and the coupling effect of optimized band structure and crystal morphology. This study not only provides new insights for further enhancing the photocatalytic performance of CN-based materials but also lays a solid foundation for their practical applications in sustainable energy and environmental remediation.