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Identification of Photoexcited Electron Relaxation in a Cobalt Phosphide Modified Carbon Nitride Photocatalyst
Author(s) -
Pei Guang Xian,
Dzade Nelson Y.,
Zhang Yue,
Hofmann Jan P.,
Leeuw Nora H.,
Weckhuysen Bert M.
Publication year - 2021
Publication title -
chemphotochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.13
H-Index - 18
ISSN - 2367-0932
DOI - 10.1002/cptc.202000259
Subject(s) - phosphide , electron transfer , carbon nitride , relaxation (psychology) , catalysis , nanosecond , transition metal , cobalt , chemistry , photocatalysis , materials science , density functional theory , analytical chemistry (journal) , photochemistry , inorganic chemistry , computational chemistry , laser , physics , psychology , social psychology , biochemistry , chromatography , optics
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‐C 3 N 4 ) 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‐C 3 N 4 , with their half‐life times (t 50% ) of 2.5 and 1.8 ns, respectively. The formation of a CoP co‐catalyst compound promoted the electron relaxation (t 50% =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‐C 3 N 4 to reactants.