Construction of Large-Scale Ultrathin Graphitic Carbon Nitride Nanosheets by a Hydrogen-Bond-Assisted Strategy for Improved Photocatalytic Hydrogen Production and Ciprofloxacin Degradation Activity

Two-dimensional nanosheets have attracted attention because of their fascinating properties in areas such as photocatalysis, sensors, and energy storage. Herein, a facile hydrogen-bond-assisted approach was designed to prepare graphitic carbon nitride (g-C₃N₄) with large-scale ultrathin nanosheets. Compared with previous methods, this method is simple, economical, and eco-friendly. The as-prepared ultrathin g-C₃N₄ nanosheets have a few-layer thickness of 2–3 nm and exhibit a significantly enhanced photocatalytic activity in both H₂ production and ciprofloxacin degradation under visible light compared to pristine g-C₃N₄. The enhanced photocatalytic activity is attributed to the minimal sheet thickness, high surface area, increased band gap, outstanding electron transport ability, and long charge-carrier lifetime. In addition, the possible formation mechanism, transfer and separation behavior of the charge carriers, and the photocatalytic mechanism are discussed. This work presents a new hydrogen-bond-assisted self-assembly strategy for the preparation of ultrathin g-C₃N₄ nanosheets for application in photocatalysis.