Eur. Phys. J. Plus (2019) 134: 186
https://doi.org/10.1140/epjp/i2019-12629-7

Regular Article

Solvothermal synthesis of BiVO₄/WO₃ heterostructures and their applicability towards electrochemical water oxidation reactions

¹ Advanced Functional Materials Research Centre, Department of Physics, Koneru Lakshmaiah Education Foundation, Vaddeswaram, Guntur, 522502, Andhra Pradesh, India
² Department of Physics, GVP College of Engineering (A), Madhurawada, Visakhapatnam, 530048, Andhra Pradesh, India

^* e-mail: dasaradh4phy@gmail.com

Received: 3 December 2018
Accepted: 14 March 2019
Published online: 3 May 2019

Abstract

Bismuth vanadate (BiVO₄) and its heterostructures with tungstate (WO₃) were prepared by solvothermal technique. Phase purity of these compounds was analysed by collecting powder. X-ray diffraction data revealed the co-existence of both BiVO₄ and WO₃ phases. Transmission electron microscopic measurements on these samples revealed that the average particles sizes of these heterostructures are in the submicron range. Optical band gap is found in the range of 2.30 to 2.45 eV by using UV-visible spectrometer. Optical spectra reveal two distinct absorption edges corresponding to both existing phases. Electrochemical activity of BiVO₄ and BiVO₄/WO₃ heterostructures was studied using electrochemical workstation for applicability of oxygen evolution reaction (OER). These results indicate that the electrochemical activity was improved by forming heterostructures as compared with pristine compounds. From the Tafel slope analysis, it was found that the second electron transfer step is the rate determining step in OER mechanism in BiVO₄/WO₃ heterostructures.