One-Step Synthesis of Alkali Metal-Hydroxyl Double Modified Graphite Phase Carbon Nitride and Photocatalytic Degradation of Phenolic Compounds

Abstract

In this work, potassium ion-hydroxyl double modified graphite phase carbon nitride (KCN–OH) was synthesized in one step by alkali hydrothermal (AH) method. The as-prepared catalysts were characterized by XRD, FT-IR, UV–Vis, N2 adsorption, SEM, XPS, PL, ESR, TPD and EIS. The introduction of potassium ion causes the reduced crystal size, increased specific surface area and promoted electron–hole separation efficiency of as-prepared catalyst. The hydroxyl group not only further improves the electron–hole separation efficiency but, as the electron donor group, can also make stronger interaction between catalyst and acidic phenolic compounds. The photocatalytic degradation of phenol was investigated under visible light. The results show that the phenol degradation rate constant of KCN–OH is 0.22 h[Formula: see text] under visible light, which is over 3.7 and 2.0 times higher than that of neat g-C3N4 and single hydroxyl-modified g-C3N4. KCN–OH also displays outstanding catalytic and structural stability. The possible reaction mechanism is discussed in this paper.