α-Fe2O3/ZnO heterostructure for enhanced photocatalytic and antibacterial activity

Abstract

This paper reports the accomplishment of a noticeable enhancement in the photodegradation and antibacterial activity of α-Fe2O3 by a heterostructure formation between α-Fe2O3 and ZnO flakes. The heterostructure yields 97% photodegradation of methylene blue pollutant in water within 180 min, which is a fourfold increase compared to that observed with a pure α-Fe2O3 nanostructure. Further characterisations indicate that the improved results are attributable to the reduction in optical band gap, the increased electrical conductivity, the improved spatial separation of carriers and the enhanced amount of available hydroxyl radicals for the reaction. The stability and reusability of the photocatalysts are confirmed for four consecutive cycles of operations. The phase identification and structural studies are done using x-ray diffraction, transmission electron microscopy and x-ray photoelectron spectroscopy in conjunction with surface morphology from field emission scanning electron microscopy. The enhancement of room temperature electrical conductivity by five times and band gap reduction from 1.98 eV to 1.75 eV for the heterostructures, when compared with α-Fe2O3 nanostructures, are obtained from voltage–current measurements and optical reflectance spectra.