Identification of Photoexcited Electron Relaxation in a Cobalt Phosphide Modified Carbon Nitride Photocatalyst

Guang X. Pei, Nelson Y. Dzade, Yue Zhang, Jan P. Hofmann, Nora H. de Leeuw, Bert M. Weckhuysen (Corresponding author)

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Transition metal phosphides have been recognized as efficient co-catalysts to boost the activity of semiconductor photocatalysts. However, a rigorous and quantitative understanding is still to be developed about how transition metal phosphides influence photoexcited electron dynamics. Here, we present a nanosecond time-resolved transient absorption spectroscopy (TAS) study of the photoexcited electron dynamics in carbon nitrides (g-C3N4) before and after Co and/or P modifications. Our spectroscopic study showed that Co or P lowered the initial electron density, whereas they promoted the photoexcited electron relaxation of g-C3N4, with their half-life times (t50%) of 2.5 and 1.8 ns, respectively. The formation of a CoP co-catalyst compound promoted the electron relaxation (t50%=2.8 ns) without significantly lowering the charge separation efficiency. Density functional theory (DFT) calculations were undertaken to explore the underlying fundamental reasons and they further predicted that CoP, compared to Co or P modification, better facilitates photoexcited electron transfer from g-C3N4 to reactants.

Original languageEnglish
Number of pages6
JournalChemPhotoChem
VolumeXX
Issue numberXX
DOIs
Publication statusAccepted/In press - 7 Jan 2021

Keywords

  • carbon nitride
  • cobalt phosphide
  • electron relaxation
  • photocatalysis
  • transient absorption spectroscopy

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