Cu2O photocatalyst: Activity enhancement driven by concave surface

Xinxin Lu, Judy N. Hart, Yin Yao, Cui Ying Toe, Jason Scott, Yun Hau Ng*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

The study of the Cu2O concave surfaces has attracted significant attention, in which most work to date has focused primarily on investigating the formation mechanism and catalytic performance. However, the photoinduced charge behavior of concave surfaces and the origins of improved photocatalytic performance, that are important for understanding photogenerated charge separation and migration, have not been thoroughly explored. Here, we demonstrate that the presence of concave surfaces on the Cu2O {100} facet facilitates the capture of photogenerated electrons. Density functional theory (DFT) calculations of the surface energies and charge distribution revealed that the concave surfaces are catalytically active due to the presence of under-coordinated copper atoms with increased charge relative to copper atoms on flat surfaces. This was further supported by comparing the surface potentials of the concave and flat regions on the Cu2O {100} surface, which were measured by Kelvin probe force microscopy (KPFM). The obtained surface potentials confirmed that the {100} concave surfaces have a gradient decrease of surface work function, inducing an efficient built-in electric field. This was visually demonstrated by the selective photodeposition of Pt particles on the concavities of the {100} surfaces. The charge distribution effect was observed and verified by both the theoretical and experimental means, whereby Cu2O particles with the {100} concave surfaces exhibited better performance in both photoelectrochemical (PEC) measurement and photocatalytic H2 evolution.

Original languageEnglish (US)
Article number100422
JournalMaterials Today Energy
Volume16
DOIs
StatePublished - Jun 2020

Keywords

  • CuO concave surface
  • DFT calculations
  • KPFM measurement
  • Photocatalytic activity
  • Photoelectrochemistry

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Materials Science (miscellaneous)
  • Nuclear Energy and Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology

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