Phosphorous doped carbon nitride nanobelts for photodegradation of emerging contaminants and hydrogen evolution

Abstract

Photocatalysis has demonstrated great potentials for both environmental remediation and green energy production. In this study, a simple solvothermal template-free approach was employed for the first time to synthesize phosphorous doped carbon nitride nanobelt (PCNNB). Advanced characterizations, for instance, ¹³C NMR, ³¹P NMR, and XPS results indicated that P was substitutionally doped at the corner-carbon of the carbon nitride frameworks. The introduction of P dopants inhibited the polymerization between NH₂ groups within PCNNB, enabling the decrease in nanobelt width for the exposure of more active sites. Therefore, the optimized P-CN-NB-2 (derived from 0.2 mM H₃PO₄) rendered enhanced p-hydroxybenzoic acid (HBA) degradation nearly 66-fold higher than bulk g-C₃N₄, among the most efficient g-C₃N₄-based photocatalysts as reported. In addition, the P-CN-NB-1 (derived from 0.02 mM H₃PO₄) exhibited about 2 times higher H₂ evolution rate than CNNB. Density functional theory (DFT) calculations were also conducted to provide insights into the mechanism.