Tandem Structures Semiconductors Based on TiO2_SnO2 and ZnO_SnO2 for Photocatalytic Organic Pollutant Removal.

Alexandru Enesca,Luminita Isac

doi:10.3390/nano11010200

Alexandru Enesca, Luminita Isac

Open Access

https://doi.org/10.3390/nano11010200

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Abstract

The photocatalyst materials correlation with the radiation scenario and pollutant molecules can have a significant influence on the overall photocatalytic efficiency. This work aims to outline the significance of optimizing the components mass ratio into a tandem structure in order to increase the photocatalytic activity toward pollutant removal. ZnO_SnO2 and TiO2_SnO2 tandem structures were obtained by the doctor blade technique using different mass ratios between the components. The samples contain metal oxides with crystalline structures and the morphology is influenced by the main component. The photocatalytic activity was tested using three radiation scenarios (UV, UV-Vis, and Vis) and two pollutant molecules (tartrazine and acetamiprid). The results indicate that the photocatalytic activity of the tandem structures is influenced by the radiation wavelength and pollutant molecule. The TiO2_SnO2 exhibit 90% photocatalytic efficiency under UV radiation in the presence of tartrazine, while ZnO_SnO2 exhibit 73% photocatalytic efficiency in the same experimental conditions. The kinetic evaluation indicate that ZnO_SnO2 (2:1) have a higher reaction rate comparing with TiO2_SnO2 (1:2) under UV radiation in the presence of acetamiprid.

Highlights

The semiconductor-mediated photocatalysis is considered as a promising pathway of removing various pollutants from aqueous and gaseous phase by directly harvesting and utilizing the solar energy [1,2,3]
This paper presents the correlation between the components mass ratio in a tandem structure and the photocatalytic activity using different radiation scenarios and pollutant molecules
The photocatalytic activity evaluation shows that the highest efficiency (90%) for Tr dye removal was obtained for sample TiO2 _SnO2 (2:1) under UV radiation

Summary

Introduction

The semiconductor-mediated photocatalysis is considered as a promising pathway of removing various pollutants from aqueous and gaseous phase by directly harvesting and utilizing the solar energy [1,2,3]. Advanced oxidation processes (AOPs) are considered as future alternative to traditional methods of removing organic pollutants: pharmaceutical active compounds [28,29], pesticides [30,31], dyes [32,33], volatile organic compounds [34,35], etc. The sustainability represents an important advantage of AOPs due to the use of light radiation as the main energy source to provide oxidative species responsible for pollutant mineralization [36,37,38]

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