Defect Engineering of WO3 by Rapid Flame Reduction for Efficient Photoelectrochemical Conversion of Methane into Liquid Oxygenates

Ho Kun Woo, Ankit Kumar Gautam, Jaxiry S. Barroso-Martínez, Arthur P. Baddorf, Kai Zhou, Yoon Young Choi, Jiajun He, Alexander V. Mironenko, Joaquín Rodríguez-López, Lili Cai

Research output: Contribution to journalArticlepeer-review

Abstract

Photoelectrochemical (PEC) conversion is a promising way to use methane (CH4) as a chemical building block without harsh conditions. However, the PEC conversion of CH4 to value-added chemicals remains challenging due to the thermodynamically favorable overoxidation of CH4. Here, we report WO3 nanotube (NT) photoelectrocatalysts for PEC CH4 conversion with high liquid product selectivity through defect engineering. By tuning the flame reduction treatment, we carefully controlled the oxygen vacancies of WO3 NTs. The optimally reduced WO3 NTs suppressed overoxidation of CH4 showing a high total C1 liquid selectivity of 69.4% and a production rate of 0.174 μmol cm-2 h-1. Scanning electrochemical microscopy revealed that oxygen vacancies can restrain the production of hydroxyl radicals, which, in excess, could further oxidize C1 intermediates to CO2. Additionally, band diagram analysis and computational studies elucidated that oxygen vacancies thermodynamically suppress overoxidation. This work introduces a strategy for understanding and controlling the selectivity of photoelectrocatalysts for direct conversion of CH4 to liquids.

Original languageEnglish (US)
Pages (from-to)11493-11500
Number of pages8
JournalNano letters
Volume23
Issue number24
DOIs
StatePublished - Dec 27 2023

Keywords

  • defect engineering
  • methane oxidation
  • photoelectrochemical conversion
  • rapid flame reduction
  • tungsten trioxide

ASJC Scopus subject areas

  • General Chemistry
  • Condensed Matter Physics
  • Mechanical Engineering
  • Bioengineering
  • General Materials Science

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