G-C3N4 modified by hydroxyl group on the surface prepared by double salt enhanced the visible light photocatalytic activity

Abstract

In this paper, g-C3N4 was modified by the synergistic effect of double salt KCl-(NH4)2CO3, and porous g-C3N4 with hydroxylated surface was prepared. Combined with a series of characterization (XRD, SEM, BET, FTIR, UV–vis DRS and XPS) and density functional theory (DFT) analysis, it is confirmed that KCl can cooperate with ammonium salt (NH4)2CO3 to produce rich pore structure, and (NH4)2CO3, as an alkaline slow-release agent, can assist KCl to further enhance hydroxylation. KCl-(NH4)2CO3 not only plays a synergistic role in pore formation, but also introduces hydroxyl and cyano groups, which improves the hydrophilicity of g-C3N4, promotes the separation efficiency of photo-generated carriers, and is beneficial to enhance the photocatalytic activity. Taking methyl orange (MO) as the model of pollutant degradation, and proposed the possible degradation mechanism. This study provides a simple, efficient and widely applicable method for modifying g-C3N4 to improve its activity.