Understanding the charge transfer dynamics of the Cu2WS4–CNT–FeOOH ternary composite for photo-electrochemical studies

Ternary transition metal chalcogenide (Cu2WS4) is a semiconductor with a band gap of 2.1 eV and could be a promising candidate for photoelectrochemical water splitting and solar energy conversion applications. Despite numerous reports on ternary transition metal chalcogenides, this semiconductor...

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Bibliographic Details
Published in:Physical chemistry chemical physics : PCCP 2023-11, Vol.25 (45), p.30867-30879
Main Authors: Dagar, Preeti, Ghorai, Nandan, Bungla, Manisha, Ghosh, Hirendra N, Ganguli, Ashok K
Format: Article
Language:English
Subjects:
Chalcogenides
Charge transfer
Current carriers
Electrochemical analysis
Multi wall carbon nanotubes
Oxidation
Photoelectric effect
Separation
Solar energy conversion
Transition metal compounds
Water splitting
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Summary:Ternary transition metal chalcogenide (Cu2WS4) is a semiconductor with a band gap of 2.1 eV and could be a promising candidate for photoelectrochemical water splitting and solar energy conversion applications. Despite numerous reports on ternary transition metal chalcogenides, this semiconductor's ultrafast charge transfer dynamics remain unknown. Here, we report on charge carrier dynamics in a pristine Cu2WS4 system with the aid of ultrafast transient (TA) pump–probe spectroscopy and a hot carrier transfer process from Cu2WS4 to multi-walled carbon nanotubes (CNTs) and FeOOH has been observed. Furthermore, we have explored Cu2WS4–FeOOH having a type-II composite for photo-electrochemical (PEC) water oxidation and modified this with the addition of multi-walled carbon nanotubes to expedite the charge-transfer processes and photo-anodic performance. The photo-electrochemical studies demonstrate that the Cu2WS4–CNT, Cu2WS4–FeOOH, and Cu2WS4–CNT–FeOOH provide nearly 3-, 8- and 12-fold enhancement in photocurrent density relative to the bare Cu2WS4 photo-anode at 1.23 V vs. RHE. These photo-electrochemical studies support the results obtained from the TA investigation and further prove the higher charge separation in the ternary composite system. These studies probe the excited states and provide evidence of longer charge separation in the binary and ternary composites, responsible for their remarkable photo-electrochemical performance.
ISSN:1463-9076
1463-9084
DOI:10.1039/d3cp03498d