Enhanced Photocatalytic Performance of Carbon Nitride through Modification of Edge Sites with Cellulose-Derived Carbon Species for H2 Evolution and Tetracycline Degradation

Due to the high electron–hole recombination rate of carbon nitride (CN) catalysts, their photocatalytic efficiency is severely limited. In particular, the inefficiency of the random migration of charges in the plane is not conducive to charge transfer. Herein, an edge-modified carbon nitride (CHC–CNx) photocatalyst was prepared by introducing cellulose-derived carbon species on the edge of the CN, resulting in efficient carrier separation and increased light absorption capacity. According to the characterization results, the carbon species grafted on the edge of CN attracted electrons to move directionally from the surface to the edge during the photocatalytic process, retaining a large amount of charge and generating free radicals, which are conducive to improving photocatalytic activity. Simultaneously, the addition of carbon species causes a decrease in resistivity, which aids in the efficient transport of carriers. When using CHC–CN5 as a photocatalyst to produce H2 and degrade TC, the H2 production rate reached 3436.0 μmol h–1 g–1, and the TC degradation rate could be 80.2% in 60 min. Finally, the photodegradation mechanism is discussed by measuring the intermediate products of photocatalytic TC degradation, and the biological toxicity of the degradation products is assessed. This paper explores a method to improve the photocatalytic performance by modifying the molecular edge of CN using cellulose as a carbon species donor after calcination.