Facile Fabrication of Large-Aspect-Ratio g-C₃N₄ Nanosheets for Enhanced Photocatalytic Hydrogen Evolution

Exfoliation of bulk graphitic carbon nitride (BCN) into two-dimensional (2D) nanosheets is one of the effective strategies to improve its photocatalytic performance. Compared with BCN, the 2D g-C₃N₄ nanosheets (CNNS) have larger specific surface areas and more reaction sites. With the etching assistance of anhydrous ethylenediamine, BCN can be successfully peeled off into 2D CNNS with a large lateral size of more than 15 μm which is much larger than that of other works. After appropriate etch by anhydrous ethylenediamine, the specific surface area of g-C₃N₄ expands from 4.7 to 31.1 m² g^-1 and the photocatalytic hydrogen evolution rate increases 7.4 times, from 4.8 to 35.3 μmol h^-1. In contrast to other reported methods, the strategy to fabricate 2D CNNS in this work is convenient and it is the first time to report the fabrication of 2D CNNS with the assistance of alkaline reagent.