Electronic structure manipulation of graphene dots for effective hydrogen evolution from photocatalytic water decomposition

Ba Son Nguyen, Yuan Kai Xiao, Chun Yan Shih, Van Can Nguyen, Wei Yang Chou, Hsisheng Teng

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

This paper presents a heteroatom doping strategy to manipulate the structure of graphene-based photocatalysts for effective hydrogen production from aqueous solution. Oxygenation of graphene creates a bandgap to produce semiconducting graphene oxide, nitrogen doping extends the resonant π-conjugation to prolong the charge lifetime, and sulfur doping breaks the electron neutrality to facilitate charge transfer. Accordingly, ammonia-treated sulfur-nitrogen-co-doped graphene oxide dots (A-SNGODs) are synthesized by annealing graphene oxide sheets in sulfur-ammonia, oxidizing the sheets into dots, and then hydrothermally treating the dots in ammonia. The A-SNGODs exhibit a high nitrogen content in terms of quaternary and amide groups that are formed through sulfur-mediated reactions. The peripheral amide facilitates orbital conjugations to enhance the photocatalytic activity, whereas the quaternary nitrogen patches vacancy defects to improve stability. The simultaneous presence of electron-withdrawing S and electron-donating N atoms in the A-SNGODs facilitates charge separation and results in reactive electrons. When suspended in an aqueous triethanolamine solution, Pt-deposited A-SNGODs demonstrate a hydrogen-evolution quantum yield of 29% under monochromatic 420 nm irradiation. The A-SNGODs exhibit little activity decay under 6-day visible-light irradiation. This study demonstrates the excellence of the heteroatom-doping strategy in producing stable and active graphene-based materials for photoenergy conversion.

Original languageEnglish
Pages (from-to)10721-10730
Number of pages10
JournalNanoscale
Volume10
Issue number22
DOIs
Publication statusPublished - 2018 Jun 14

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All Science Journal Classification (ASJC) codes

  • Materials Science(all)

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