Identification of Photoexcited Electron Relaxation in a Cobalt Phosphide Modified Carbon Nitride Photocatalyst. Issue 4 (26th January 2021)

• Record Type: Journal Article
• Authors: Pei, Guang Xian; Dzade, Nelson Y.; Zhang, Yue; Hofmann, Jan P.; de Leeuw, Nora H.; Weckhuysen, Bert M.
• Is Part Of: ChemPhotoChem. Volume 5:Issue 4(2021)
• Page Start: 330
• Page End: 334
• Publication Date: 2021-01-26
• Subjects: carbon nitride -- cobalt phosphide -- electron relaxation -- photocatalysis -- transient absorption spectroscopy; Photochemistry -- Periodicals; Periodicals; Electronic journals; 541.35
• DOI: 10.1002/cptc.202000259
• Languages: English
• ISSNs: 2367-0932

Abstract

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‐C3 N4 ) 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‐C3 N4, 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‐C3 N4 to reactants. Abstract : Rest and relaxation : A combined nanosecond time‐resolved transient absorption spectroscopy and theoretical study was employed to investigate the photoexcited electron dynamics in a cobalt phosphide modified carbon nitride photocatalyst, which provided a mechanistic understanding of cobalt phosphide effects on the electron relaxation process.