Rapid thermal vapor condensation towards crystalline carbon nitride film with improved photoelectrochemical activity

Graphitic carbon nitride (g-CN), as an orderly structured polymer derivative, has been widely concerned for its photocatalytic ability due to its metal-free nature and unique properties. However, the photoelectrochemical (PEC) application of g-CN is still hindered by the difficulty of forming high-quality films with good uniformity and crystallinity. Herein, we studied the rapid thermal vapor condensation (RTVC) for growing g-CN films with improved PEC activity. The polycondensation and polymerization reactions of precursor melamine molecules under the optimized temperature 600 °C and calcination time 20 min resulted in better crystallinity of g-CN films. Remarkably, the growth of g-CN film based on the coalescence of unambiguous hexagonal nanosheets was observed, as corroborated by scanning electron microscopy and transmission electron microscopy. This novel RTVC method offers a fast and easy strategy for improving the crystallinity of g-CN films through controlling the thermal dynamics and kinetics of film growth from temperature and time.