Precursor-modified strategy to synthesize thin porous amino-rich graphitic carbon nitride with enhanced photocatalytic degradation of RhB and hydrogen evolution performances

Abstract

The photocatalytic activity of carbon nitride (CN) materials is mainly limited to small specific surface areas, limited solar absorption, and low separation and mobility of photoinduced carriers. In this study, we developed a precursor-modified strategy for the synthesis of graphitic CN with highly efficient photocatalytic performance. The precursor dicyandiamide reformed by different acids undergoes a basic structural change and transforms into diverse new precursors. The thin porous amino-rich HNO3-CN (5H-CN) was calcined by dicyandiamidine nitrate, formed by concentrated nitric acid modified dicyandiamide, and presented the best photocatalytic degradation rate of RhB, more than 34 times that of bulk graphitic CN. Moreover, the photocatalytic hydrogen evolution rate of 5H-CN significantly improved. The TG-DSC-FTIR analyses indicated that the distinguishing thermal polymerization process of 5H-CN led to its thin porous amino-rich structure, and the theoretical calculations revealed that the negative conduction band potential of 5H-CN was attributed to its amino-rich structure. It is anticipated that the thin porous structure and the negative conduction band position of 5H-CN play important roles in the improvement of the photocatalytic performance. This study demonstrates that precursor modification is a promising project to induce a new thermal polycondensation process for the synthesis of CN with enhanced photocatalytic performance.