All-solid-state Z-scheme In2S3/CQDs/TiO2 heterojunction for highly efficient degradation of ofloxacin

Abstract

An all-solid-state Z-scheme In2S3/carbon quantum dots (CQDs)/TiO2 heterojunction was successfully prepared using a two-step hydrothermal method. Under simulated sunlight, samples exhibited the best photoelectrochemical properties, resulting in enhanced degradation of ofloxacin. The 0.2In2S3/CQDs-2/titanium dioxide nanoarray (TNR) exhibited the highest photocurrent density, which was 16.9 times higher than that of the original TNR. The visible-light degradation rate of ofloxacin was 92.7% after 120 min, and the first-order kinetic constant was 0.0186 min−1 (7.41 and 7.01 times higher than those of the original TNR and In2S3, respectively). The excellent photoelectrochemical performance was mainly attributed to the CQDs acting as an electron mediator, promoting the separation of photogenerated electron-hole pairs and maintaining high redox capacity. A mechanism of an all-solid-state Z-scheme In2S3/CQDs/TiO2 heterojunction for the degradation of ofloxacin was proposed, providing a novel approach for the degradation of ofloxacin by semiconductor photocatalysts.