CuInS2/Mg(OH)2 Nanosheets for the Enhanced Visible-Light Photocatalytic Degradation of Tetracycline.

Xiaogang Zheng,Xiaojin Fu,Yiting Mao,Xinhui Liu,Jing Wen

doi:10.3390/nano9111567

Abstract

CuInS2/Mg(OH)2 (CIS/Mg(OH)2) nanosheets have been prepared for the visible light activated photodegradation of tetracycline hydrochloride (TCH). The introduction of CuInS2 has proven to enhance the photocatalytic activity of Mg(OH)2 nanosheets. It’s ascribed to the enhanced transfer and separation of charge carriers at the junction interface between CuInS2 and Mg(OH)2. The photocatalytic activity of obtained CIS/Mg(OH)2 is greatly affected by CuInS2 content, pH value, and inorganic ions. Among these samples, 2-CIS/Mg(OH)2 exhibits the excellent photocatalytic activity and durability for the visible light driven removal of TCH after five cycle times. Atomic force microscope (AFM) images indicate that the surface roughness of 2-CIS/Mg(OH)2 is intensively influenced in adsorption-photocatalysis process. The •O2− and •OH radicals are vital for the visible light driven photocatalytic activity of 2-CIS/Mg(OH)2 for TCH removal.

Highlights

Tetracycline hydrochloride (TCH, C22H24N2O8·HCl), as a broad-spectrum antibiotic, has been intensively applied for the therapy of human and livestock infections [1]
In contrast with the sphere-like clusters of 1-CIS/Mg(OH)2 with a nominal CuInS2 content of 3.0 wt. % (Figure 1A,B), 2-CIS/Mg(OH)2 with a nominal CuInS2 content of 5.0 wt. % (Figure 1C,D) becomes weaker agglomeration, which are further confirmed by TEM images (Figure 2A,B)
Based on the TEM image of 2-CIS/Mg(OH)2 (Figure S3), elemental mapping images (Figure 2E–I) indicate that there are Mg, O, Cu, In, and S elements exist in 2-CIS/Mg(OH)2, meaning the successful synthesis of CuInS2/Mg(OH)2 composites

Summary

Introduction

Tetracycline hydrochloride (TCH, C22H24N2O8·HCl), as a broad-spectrum antibiotic, has been intensively applied for the therapy of human and livestock infections [1]. As a typical advanced oxidation route, semiconductor-based photocatalysis has been paid great attention due to its low cost, non-pollution, and high efficiency [15,16,17,18,19,20] In such a sustainable and green process, a proper semiconductor serves as the photocatalyst to participate in the oxidation reaction of TCH removal under solar light irradiation. As a direct I-III-VI band gap semiconductor consisting of one divalent, one trivalent, and two divalent cations, copper indium sulfide (CuInS2) is considered as a potential visible-light photocatalyst owing to its narrow band gap (~1.5 eV), large optical absorption coefficient (α > 105 cm−1) and efficient solar energy conversion [21,22,23] The phase structures such as wurtzite, zinc blende and chalcopyrite of CuInS2 can greatly affect its luminescence property. The efficient hole-capture materials are still explored for improving the hole transfer and affording the stability of CuInS2

Methods

Results

Conclusion