Introducing oxygen cacancies to tune Cu2O by Sn ion-doped for high-effective photocatalytic degradation of norfloxacin in wastewater

Abstract

Photocatalytic materials have attracted considerable attention owing to its positive environmental impact and efficiency in wastewater treatment. Herein, tin (Sn)-doped copper oxide (Cu₂O) photocatalysts were successfully synthesized via a facile hydrothermal approach. The doping of Sn ions into the Cu₂O lattice promoted the formation of more oxygen vacancies, which increased the separation efficiency of photogenerated carriers and enhanced photocatalytic activity. Moreover, the presence of Sn ions enhanced light absorption and the specific surface area of Cu₂O, and reduced photogenerated carriers recombination. The synergistic effect of the abovementioned advantages, induced excellent photocatalytic activity to the as-prepared catalysts. Tin chloride (30 mg)-doped Cu₂O showed optimal photocatalytic properties with the highest norfloxacin degradation rate of 83.9 % in 140 min under visible light irradiation. Hydroxy radicals played a major role during degradation as demonstrated by the capturing of active species experiment and EPR testing. Photocatalytic mechanisms and possible degradation pathways were proposed based on Perdew-Burke-Ernzerhof and high-performance liquid chromatography-mass spectrometry techniques. The toxicity analyses of the intermediates proved their low toxicity. Repeated cycling experiments confirmed the excellent stability of the catalysts. This work provides a feasible strategy for fabricating high-performance Cu₂O-based photocatalysts.