Two‐step pyrolysis preparation of co‐doped porous g‐C₃N₄ with Co–N coordination bond for dye efficient degradation driven by visible light

Abstract

BACKGROUND In this study, porous g‐C3N4 (PCN) doped with different masses of cobalt (1%, 3%, 5%, 10%) (Co‐PCN) were obtained by a simple two‐step calcination method. Herein, choosing Rhodamine B (RB) as target pollutant, RB degradation efficiency of Co‐PCN (5%) driven by visible light was as high as 98.1%, which is 1.28 and 2.18 times that of PCN and g‐C3N4, respectively. RESULTS Characterization results confirmed that Co‐PCN showed abundant pore structures and was doped with cobalt by Co–N coordination bond without destroying its crystal structure. In addition, the band gap of Co‐PCN was adjusted from 2.44 eV (g‐C3N4) to 2.28 eV, and its photocurrent intensity was 1.5 times that of g‐C3N4. The capture experiments showed that • O2− and h+ are the main active species in the reaction. CONCLUSION Combined with analysis of the semiconductor energy band theory, the excellent photocatalytic performance of Co‐PCN is attributable to the synergistic effect of its stronger visible light absorption ability obtained by adjusting band gap energy and the host‐guest interaction between cobalt and g‐C3N4. In addition, Co‐PCN possessed the satisfactory stability and photocatalytic degradation ability in actual water matrix, which is expected to provide a new strategy for actual wastewater treatment. © 2021 Society of Chemical Industry (SCI).