Highly efficient ultrasound-driven Cu-MOF/ZnWO4 heterostructure: An efficient visible-light photocatalyst with robust stability for complete degradation of tetracycline

Jenson Samraj Jeyaprakash; Manju Rajamani; Claudia L Bianchi; Muthupandian Ashokkumar; Bernaurdshaw Neppolian

doi:10.1016/j.ultsonch.2023.106624

Highly efficient ultrasound-driven Cu-MOF/ZnWO₄ heterostructure: An efficient visible-light photocatalyst with robust stability for complete degradation of tetracycline

Ultrason Sonochem. 2023 Nov:100:106624. doi: 10.1016/j.ultsonch.2023.106624. Epub 2023 Oct 9.

Authors

Jenson Samraj Jeyaprakash¹, Manju Rajamani¹, Claudia L Bianchi², Muthupandian Ashokkumar³, Bernaurdshaw Neppolian⁴

Affiliations

¹ Department of Chemistry, Faculty of Engineering and Technology, SRM Institute of Science and Technology, Kattankulathur, Chennai 603203, India.
² Department of Chemistry, University of Milan, Via Golgi 19, 20133 Milano, Italy; Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM), via Giusti 9, 50121 Florence, Italy.
³ Sonochemistry Group, School of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia.
⁴ Department of Chemistry, Faculty of Engineering and Technology, SRM Institute of Science and Technology, Kattankulathur, Chennai 603203, India. Electronic address: neppolib@srmist.edu.in.

Abstract

Metal-organic frameworks (MOFs) are a significant class of porous, crystalline materials composed of metal ions (clusters) and organic ligands. The potential use of copper MOF (Cu-BTC) for the sonophotocatalytic degradation of Tetracycline (TC) antibiotic was investigated in this study. To enhance its catalytic efficiency, S-scheme heterojunction was created by combining Cu-BTC with Zinc tungstate (ZnWO₄), employing an ultrasound-assisted hydrothermal method. The results demonstrated that the Cu-BTC/ZnWO₄ heterojunction exhibited complete removal of TC within 60 min under simultaneous irradiation of visible light and ultrasound. Interestingly, the sonophotocatalytic degradation of TC using the Cu-BTC/ZnWO₄ heterojunction showed superior efficiency (with a synergy index of ∼0.70) compared to individual sonocatalytic and photocatalytic degradation processes using the same heterojunction. This enhancement in sonophotocatalytic activity can be attributed to the formation of an S-scheme heterojunction between Cu-BTC and ZnWO₄. Within this heterojunction, electrons migrated from Cu-BTC to ZnWO₄, facilitated by the interface between the two materials. Under visible light irradiation, the built-in electric field, band edge bending, and coulomb interaction synergistically inhibited the recombination of electron-hole pairs. Consequently, the accumulated electrons in Cu-BTC and holes in ZnWO₄ actively participated in the redox reactions, generating free radicals that effectively attacked the TC molecules. This study offers valuable perspectives on the application of a newly developed S-scheme heterojunction photocatalyst, demonstrating its effectiveness in efficiently eliminating diverse recalcitrant pollutants via sonophotocatalytic degradation.

Keywords: Copper-BTC; S-scheme heterojunction; Sonophotocatalytic degradation; Tetracycline antibiotic; Zinc tungstate.