Tailoring the Performance of ZnO for Oxygen Evolution by Effective Transition Metal Doping

Qiuhua Liang, Geert Brocks*, Vivek Sinha, Anja Bieberle-Hütter*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

In the quest for active and inexpensive (photo)electrocatalysts, atomistic simulations of the oxygen evolution reaction (OER) are essential for understanding the catalytic process of water splitting at solid surfaces. In this paper, the enhancement of the OER by first-row transition-metal (TM) doping of the abundant semiconductor ZnO was studied using density functional theory (DFT) calculations on a substantial number of possible structures and bonding geometries. The calculated overpotential for undoped ZnO was 1.0 V. For TM dopants in the 3d series from Mn to Ni, the overpotentials decreased from 0.9 V for Mn and 0.6 V for Fe down to 0.4 V for Co, and rose again to 0.5 V for Ni and 0.8 V for Cu. The overpotentials were analyzed in terms of the binding to the surface of the species involved in the four reaction steps of the OER. The Gibbs free energies associated with the adsorption of these intermediate species increased in the series from Mn to Zn, but the difference between OH and OOH adsorption (the species involved in the first, respectively the third reaction step) was always in the range 3.0–3.3 eV, despite a considerable variation in possible bonding geometries. The bonding of the O intermediate species (involved in the second reaction step), which is optimal for Co, and to a somewhat lesser extend for Ni, then ultimately determined the overpotential. These results implied that both Co and Ni are promising dopants for increasing the activity of ZnO-based anodes for the OER.

Original languageEnglish
Pages (from-to)3064-3073
Number of pages10
JournalChemSusChem
Volume14
Issue number15
Early online date26 May 2021
DOIs
Publication statusPublished - 9 Aug 2021

Keywords

  • density functional theory
  • overpotential
  • oxygen evolution reaction
  • transition metal doping
  • ZnO
  • UT-Hybrid-D

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