Iron and Manganese Codoped Cobalt Tungstates Co1-(x+ y)Fe x Mn y WO4 as Efficient Photoelectrocatalysts for Oxygen Evolution Reaction

Muhammad Athar; Muhammad Fiaz; Muhammad Asim Farid; Muhammad Tahir; Muhammad Adnan Asghar; Sadaf Ul Hassan; Murtaza Hasan

doi:10.1021/acsomega.0c05412

Iron and Manganese Codoped Cobalt Tungstates Co_{1-(x+ y)}Fe _x Mn _y WO₄ as Efficient Photoelectrocatalysts for Oxygen Evolution Reaction

ACS Omega. 2021 Mar 10;6(11):7334-7341. doi: 10.1021/acsomega.0c05412. eCollection 2021 Mar 23.

Authors

Muhammad Athar¹, Muhammad Fiaz¹, Muhammad Asim Farid², Muhammad Tahir³, Muhammad Adnan Asghar^{1

2}, Sadaf Ul Hassan⁴, Murtaza Hasan⁵

Affiliations

¹ Institute of Chemical Sciences, Bahauddin Zakariya University, Multan 60800, Pakistan.
² Department of Chemistry, Division of Science and Technology, University of Education, Lahore, Pakistan.
³ Department of Applied Chemistry, School of Science, Xi'an Jiaotong University, Xi'an 710049, China.
⁴ Department of Chemistry, COMSATS University Islamabad, Lahore Campus, Lahore 54000, Pakistan.
⁵ Department of Biotechnology, The Institute of Biochemistry, Biotechnology and Bioinformatics, The Islamia University of Bahawalpur, Bahawalpur 63100, Pakistan.

Abstract

Photoelectrocatalysts are robust materials for the production of energy through different ways such as water splitting. Narrow optical band gaps and high overpotentials are limiting the development of photoelectrocatalysts. In this study, a series of Co_1-(x+y)Fe _x Mn _y WO₄ solid solutions of cobalt tungstate codoped with iron and manganese have been synthesized hydrothermally. The synthesized solid solutions have been characterized by powder XRD, UV-visible spectra, cyclic voltammetry (CV), and linear sweep voltammetry (LSV). They all crystallize in a wolframite-type monoclinic crystal system with space group P2/c. Doping of iron and manganese leads to narrowing of the optical band gap of Co_1-(x+y)Fe _x Mn _y WO₄ from 2.60 to 2.04 eV. The electrocatalytic activity toward oxygen evolution reaction of all of the samples has been evaluated through LSV measurements. It is found that the sample named C5, which is codoped with manganese and iron, has the lowest onset potential and needs the lowest overpotential to attain the targeted 5 mA cm^-2 and standard 10 mA cm^-2 current densities as compared with all other synthesized samples. This study shows that the synthesized tungstates can be good candidates for the photoelectrocatalytic oxygen evolution reaction.