To improve the photoelectrochemical (PEC) performance of photocatalysts, the doping strategy through covalent functionalization is often adopted to adjust material electronic structures. By contrast, this work demonstrates that the noncovalent interaction in the case of iodinated graphitic carbon nitride (g‐CN) film can also enhance the PEC performance. Through a facile synthesis method of rapid thermal vapor condensation (RTVC), the prepared iodinated g‐CN film shows a significantly improved photocurrent density (38.9 µA cm−2), three times that of pure g‐CN film (13.0 µA cm−2) at 1.23 V versus reversible hydrogen electrode. Computations reveal that the noncovalent attachment of iodine anion (I−) on g‐CN plays a crucial role in modulating the bandgap states and broadening of the visible‐light absorption range as well as the charge carrier separation with the photo‐induced hole confined to I− and electron to g‐CN film. The fully filled valence orbitals (4d105s25p6) of I− determine its noncovalent attachment on the g‐CN film and so do the iodine species of I3−, I5−, etc. This work offers a favorable synthesis method to achieve efficient doping through noncovalent charge transfer between thin film and certain dopants and provides a useful modification strategy for the establishment of multi‐channel transportation of charge carriers in general photocatalysts.

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 report the use of a rapid thermal vapor condensation (RTVC) method for growing g-CN films with improved PEC activity. The polycondensation reactions of precursor melamine molecules under the optimized temperature 600 °C and condensation 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 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.

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Highly efficient photocatalysts based on Van der Waals 2D type of heterojunction were fabricated by horizontal loading of ultrathin hexagonal SnS2 nanosheets on the surface of g-CN film via spin...