Ultrathin Crystalline Carbon Nitride Nanosheets for Highly Efficient Photocatalytic Pollutant Removal and Hydrogen Production

We present a facile bottom-up strategy to prepare crystalline polymeric carbon nitride (CCN) with ultrathin 2D nanosheet structures, which involves supramolecular self-assembly into crystalline rodlike intermediates and subsequent thermal-induced exfoliation and polycondensation. Under visible light irradiation, CCN can efficiently remove various high-concentration organic pollutants (50 mg L–1) and synergistically remove organic pollutants and heavy metal ions. The removal rates of all organic pollutants including antibiotics and dyes exceed 95% within 40 min, outperforming previously reported photocatalysts. Moreover, it also exhibits outstanding photocatalytic performance in the water-splitting reaction with a H2 evolution rate of 11.5 mmol g–1 h–1. The highly boosted activity of CCN can be attributed to the significantly improved charge separation, the increased accessible active sites, as well as the enhanced visible light absorption, benefiting from its high crystallinity and ultrathin 2D nanosheet structure. This work presents a feasible strategy for the preparation of crystalline carbon nitride nanosheets toward energy and environmental applications.