Covalently Interconnected Polymer Dot-WS2Nanosheet Heterostructure for Visible Light-Driven Hydrogen Production

Yan Ming Lai, Anil A. Kashale, Ming Ho Liu, Wei Sheng Liao, Chih Yu Chang, Wan Yi Chen, Yang Hsiang Chan, I. Wen Peter Chen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Photocatalytic hydrogen evolution is a promising solution to energy and environmental crises. The aim is to design an effective and strong photocatalyst that makes perfect use of solar energy. This is possible when catalysts have a good visible absorption ability, wide band gap, slow electron-hole pair recombination rate, and a large amount of active surface area. Considering the important properties of an excellent photocatalyst, in this work, by mixing variable amounts of chlorophyll-assisted exfoliated WS2nanosheets with the COOH and SH functional group polymer dots named P-dots-COOH and P-dots-SH, respectively, we have developed P-dots-COOH/WS2and P-dots-SH/WS2heterostructure composites. The P-dots-COOH/WS280% heterostructure composite demonstrated a slightly higher current density (∼2.6 mA/cm2) than the individual P-dots (∼1.8 mA/cm2) and exfoliated WS2nanosheets (∼2.0 mA/cm2). However, the P-dots-SH/WS280% heterostructure composite demonstrated almost 200% (∼4.6 mA/cm2) enhanced photocurrent density and low charge transfer resistance compared to P-dots-SH (∼2.0 mA/cm2) and WS2nanosheet (∼2.0 mA/cm2) materials. This was due to the coordination of the thiol functional group of P-dots-SH with the defect interface site of the chlorophyll-assisted exfoliated WS2nanosheets that reduced the charge transfer resistance, increased the number of electron-hole pairs, and reduced the electron-hole pair recombination rate. We discussed the possible photocatalytic hydrogen evolution mechanism in which the P-dots-SH valence band position was lower than the WS2valence band position. These results indicate that photogenerated electrons can be transferred from the conduction band of WS2to the conduction band of P-dots-SH, which reduces the possibility of recombination of electrons and holes and is more conducive to the transfer of electrons resulting in the hydrogen reduction potential, that is, the hydrogen production.

Original languageEnglish
Pages (from-to)2163-2174
Number of pages12
JournalACS Applied Nano Materials
Volume5
Issue number2
DOIs
StatePublished - 25 Feb 2022

Keywords

  • heterostructure
  • hydrogen evolution
  • photocatalysts
  • polymer quantum dots
  • visible light
  • WSnanosheets

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