Enhanced photocatalytic performance of NiFeO/ZnInS p-n heterojunction for efficient degradation of tetracycline.

The persistent release of tetracycline into the environment significantly endangers both ecosystems and human health. Zinc indium sulfide (ZnInS) capable to degrade tetracycline pollutants under visible light irradiation has attracted extensive attentions and great effort has been devoted to augment its catalytic efficacy. In this work, we synthesized a p-n heterojunction, NiFeO/ZnInS, to enhance the carrier migration rate and explained the intrinsic mechanism by density functional theory. When the heterojunction was formed, carriers traversed from the n-type NiFeO to the p-type ZnInS, instigating the emergence of a built-in electric field to facilitate the separation of carriers. 2 %-NiFeO/ZnInS exhibited excellent photocatalytic efficiency in tetracycline (TC) degradation and total organic carbon (TOC) removal. Compared to pure ZnInS and NiFeO, the TC degradation rates of 2 %-NiFeO/ZnInS were 2.0 times and 16.9 times higher, respectively. Additionally, 2 %-NiFeO/ZnInS had a saturation magnetization intensity of 3.05 emu/g, allowing for rapid recovery of the catalyst under a magnetic field. Superoxide radicals (O) and holes (h) were the primary active species driving the degradation process. Furthermore, potential reaction pathways of tetracycline in this photocatalytic process were determined and bioconcentration factor and developmental toxicity of the intermediate products were accessed. This work held great potentials for wastewater treatment and provided a pathway for the development of magnetic recyclable photocatalysts.