Light-Driven Catalytic Activity of Green-Synthesized SnO2/WO3- x Hetero-nanostructures

Faroha Liaqat; Urwa Tul Vosqa; Fatima Khan; Abdul Haleem; Mohammed Rafi Shaik; Mohammed Rafiq H Siddiqui; Mujeeb Khan

doi:10.1021/acsomega.3c02330

Light-Driven Catalytic Activity of Green-Synthesized SnO₂/WO_{3- x} Hetero-nanostructures

ACS Omega. 2023 May 24;8(22):20042-20055. doi: 10.1021/acsomega.3c02330. eCollection 2023 Jun 6.

Authors

Faroha Liaqat¹, Urwa Tul Vosqa¹, Fatima Khan¹, Abdul Haleem², Mohammed Rafi Shaik³, Mohammed Rafiq H Siddiqui⁴, Mujeeb Khan³

Affiliations

¹ Department of Chemistry, Quaid-i-Azam University, 45320 Islamabad, Pakistan.
² CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China.
³ Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia.
⁴ Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, United Kingdom.

Abstract

This work reports an environmentally friendly and economically feasible green synthesis of monometallic oxides (SnO₂ and WO₃) and their corresponding mixed metal oxide (SnO₂/WO_3-x) nanostructures from the aqueous Psidium guajava leaf extract for light-driven catalytic degradation of a major industrial contaminant, methylene blue (MB). P. guajava is a rich source of polyphenols that acts as a bio-reductant as well as a capping agent in the synthesis of nanostructures. The chemical composition and redox behavior of the green extract were investigated by liquid chromatography-mass spectrometry and cyclic voltammetry, respectively. Results acquired by X-ray diffraction and Fourier transform infrared spectroscopy confirm the successful formation of crystalline monometallic oxides (SnO₂ and WO₃) and bimetallic SnO₂/WO_3-x hetero-nanostructures capped with polyphenols. The structural and morphological aspects of the synthesized nanostructures were analyzed by transmission electron microscopy and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. Photocatalytic activity of the synthesized monometallic and hetero-nanostructures was investigated for the degradation of MB dye under UV light irradiation. Results indicate a higher photocatalytic degradation efficiency for mixed metal oxide nanostructures (93.5%) as compared to pristine monometallic oxides SnO₂ (35.7%) and WO₃ (74.5%). The hetero-metal oxide nanostructures prove to be better photocatalysts with reusability up to 3 cycles without any loss in degradation efficiency or stability. The enhanced photocatalytic efficiency is attributed to a synergistic effect in the hetero-nanostructures, efficient charge transportation, extended light absorption, and increased adsorption of dye due to the enlarged specific surface area.