Facet-dependent active sites of a single Cu2O particle photocatalyst for CO2 reduction to methanol

Yimin A. Wu, Ian McNulty, Cong Liu, Kah Chun Lau, Qi Liu, Arvydas P. Paulikas, Cheng Jun Sun, Zhonghou Cai, Jeffrey R. Guest, Yang Ren, Vojislav Stamenkovic, Larry A. Curtiss, Yuzi Liu, Tijana Rajh

Research output: Contribution to journalArticlepeer-review

294 Scopus citations


Atomic-level understanding of the active sites and transformation mechanisms under realistic working conditions is a prerequisite for rational design of high-performance photocatalysts. Here, by using correlated scanning fluorescence X-ray microscopy and environmental transmission electron microscopy at atmospheric pressure, in operando, we directly observe that the (110) facet of a single Cu2O photocatalyst particle is photocatalytically active for CO2 reduction to methanol while the (100) facet is inert. The oxidation state of the active sites changes from Cu(i) towards Cu(ii) due to CO2 and H2O co-adsorption and changes back to Cu(i) after CO2 conversion under visible light illumination. The Cu2O photocatalyst oxidizes water as it reduces CO2. Concomitantly, the crystal lattice expands due to CO2 adsorption then reverts after CO2 conversion. The internal quantum yield for unassisted wireless photocatalytic reduction of CO2 to methanol using Cu2O crystals is ~72%.

Original languageEnglish (US)
Pages (from-to)957-968
Number of pages12
JournalNature Energy
Issue number11
StatePublished - Nov 1 2019
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Energy Engineering and Power Technology


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