AUTHOR=Li Weidong , Qiu Jianping , Jin Haihong , Wang Yuanyuan , Ma Dandan , Zhang Xinxiang , Yang Huayun , Wang Fangyuan 

TITLE=Modifying SnS2 With Carbon Quantum Dots to Improve Photocatalytic Performance for Cr(VI) Reduction

JOURNAL=Frontiers in Chemistry

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2022.911291

DOI=10.3389/fchem.2022.911291

ISSN=2296-2646

ABSTRACT=<p>The photoreduction for hazardous Cr(VI) in industrial wastewater has been considered a “green” approach with low-cost and easy-to-go operation. SnS<sub>2</sub> is a promising narrow bandgap photocatalyst, but its low charge carrier separation efficiency should be solved first. In this work, N-doped carbon quantum dots (CQDs) were prepared and loaded onto SnS<sub>2</sub> nanoparticles <italic>via</italic> an <italic>in situ</italic> method. The resulting composite samples (NC@SnS<sub>2</sub>) were characterized, and their photocatalytic performance was discussed. SnS<sub>2</sub> nanoparticles were obtained as hexagonal ones with a bandgap of 2.19 eV. The optimal doping level for NC@SnS<sub>2</sub> was citric acid: urea:SnS<sub>2</sub> = 1.2 mmol:1.8 mmol:3.0 mmol. It showed an average diameter of 40 nm and improved photocatalytic performance, compared to pure SnS<sub>2</sub>, following a pseudo-first-order reaction with a kinetic rate constant of 0.1144 min<sup>−1</sup>. Over 97% of Cr(VI) was photo-reduced after 30 min. It was confirmed that modification of SnS<sub>2</sub> with CQDs can not only improve the light-harvesting ability but also stimulate the charge separation, which therefore can enhance the photoreactivity of SnS<sub>2</sub> toward Cr(VI) reduction. The excellent stability of NC@SnS<sub>2</sub> indicates that it is promising to be practically used in industrial wastewater purification.</p>