Molecular doping of graphitic carbon nitride for enhanced visible light-driven photodegradation of organic contaminants

Abstract

Utilizing solar energy for photodegradation of organic contaminants is an attractive strategy for environmental remediation. However, the synthesis of photocatalysts for efficient use of solar energy remains a challenge. Herein, we designed and synthesized a hierarchical and porous g-C₃N₄ (CN) via thermal polymerization of 5-amino-1H-tetrazole (ATZ) and melamine molecules. Experimental results demonstrate that the incorporation of electron-deficient ATZ into the CN structure drastically promotes the separation and transport of photoexcited charge carriers, and increases the specific surface area and pore size of the sample. Based on these unique features, the optimal CN-ATZ1 sample exhibited excellent photocatalytic activity with a rate constant of 0.091 min^-1 for the degradation of rhodamine B (RhB) under visible light irradiation, which was about 10.71 times higher than that of bulk CN. Radical trapping experiments demonstrate that the superoxide radical (•O₂⁻) is the major active species during the photodegradation process. This study provides a feasible strategy for the design and construction of g-C₃N₄ photocatalysts with high degradation activity.