Simple synthesis of 2D/3D mpg-C3N4/ZnO nanocages with built-in driven Z-scheme heterostructures: Photocatalytic degradation of tetracycline antibiotics and lifting the limitation of the complex water environment

Abstract

Tetracycline antibiotics have attracted attention due to their difficulty in being degraded by the natural environment. In this work, 2D/3D mesoporous graphitic carbon nitride (mpg-C₃N₄)/ zinc oxide (ZnO) hollow nanocage (MCNZH) complexes with Z-scheme heterostructure were prepared for the photocatalytic degradation of tetracycline antibiotics. The catalysts were characterized by SEM, TEM, BET, XRD, FT-IR, EIS, etc. The degradation of tetracycline hydrochloride (40 mg L^–1) by MCNZH (1.2 g L^–1) can reach 92.08 %. Further, the energy band structure of the catalysts were calculated and the possible degradation mechanism was proposed. The results showed that ·OH^– and ·O₂^– were the main active species, and the internal electric field suppressed the compounding of photogenerated carriers. The catalysts exhibited broad-spectrum degradation of tetracycline antibiotics. Practical sample spiking experiments on soil and river water confirmed its practicability, which provide great significance for the application of the photocatalytic technology in the practical environmental purification.