Oxygen vacancy engineering with flame heating approach towards enhanced photoelectrochemical water oxidation on WO3 photoanode

Chenyi Shao, Anum Shahid Malik, Jingfeng Han, Deng Li, Michel Dupuis, Xu Zong, Can Li

Research output: Contribution to journalArticle

Abstract

Oxygen vacancies are a double-edged sword for photoelectrochemical (PEC) devices and a comprehensive understanding on their role in PEC processes is important. Although there is existing work that illustrates their effect on PEC processes, clarifying the influence of surface and bulk oxygen vacancies, respectively, on the PEC performance is challenging. Herein, we present the fabrication of WO3 photoanodes with tunable bulk and surface oxygen vacancy with a novel two-step flame heating approach that is proving to be a powerful platform for this purpose. We found that both the conductivity and trapping state density of the WO3 photoanode increase with bulk oxygen vacancy density, leading to a volcano-like relationship between the kinetics of charge separation/transport and bulk oxygen vacancy density. Moreover, both the interfacial charge transfer rate constant and the charge recombination rate constant on the surface of the WO3 photoanode increase with surface oxygen vacancy density, which also leads to a volcano-like relationship between the charge injection efficiency and surface oxygen vacancy density. By tuning the surface and bulk oxygen vacancy density simultaneously, the PEC performance of the WO3 photoanode was increased by ca. 10 times, which illustrates the strength of delicate oxygen vacancy engineering in optimizing PEC devices.

Original languageEnglish
Article number105190
JournalNano Energy
Volume77
DOIs
Publication statusPublished - Nov 2020

Keywords

  • Charge transfer
  • Charge transport
  • Oxygen vacancy
  • Photoelectrocatalysis
  • WO

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)
  • Electrical and Electronic Engineering

Fingerprint Dive into the research topics of 'Oxygen vacancy engineering with flame heating approach towards enhanced photoelectrochemical water oxidation on WO<sub>3</sub> photoanode'. Together they form a unique fingerprint.

  • Cite this