Graphitic carbon nitride nanosheets prepared by gaseous molecules assembling for enhanced photocatalytic performance

Graphitic carbon nitride (g-C₃N₄), a new two-dimensional (2D) polymeric semiconductor, is considered as one of the most promising candidates for visible-light photocatalytic H₂ evolution. The synthesis of thin-layered g-C₃N₄ is a facile approach to enhancing its photocatalytic properties. Here, a novel, cost-efficient, and time-saving strategy is reported to obtain 2D g-C₃N₄. In this equipment, bulk g-C₃N₄ and thin-layered g-C₃N₄ (denoted as G-CN) assembled from gaseous molecules were obtained simultaneously. The thin-layered g-C₃N₄ possesses more negative conduction-band minimum (~ 0.18 eV) relative to the bulk counterparty, leading to stronger redox ability. What is more, the carrier mobility and separation efficiency are both improved. As a result, the water splitting performance and photodegradation efficiency for methylene blue on thin-layered g-C₃N₄ are dramatically improved. The H₂ evolution rate and half-time of photodegradation obtained by kinetic fitting reached 48.83 μmol h⁻¹ and about 1.5 h, which is much more superior to that of bulk g-C₃N₄. Generally, the present work may bring out new thinking to synthesize thin-layered 2D materials.