Enhanced photocatalytic hydrogen production on GaN–ZnO oxynitride by introduction of strain-induced nitrogen vacancy complexes

Kaveh Edalati, Ryoko Uehiro, Shuhei Takechi, Qing Wang, Makoto Arita, Motonori Watanabe, Tatsumi Ishihara, Zenji Horita

    Research output: Contribution to journalArticlepeer-review

    19 Citations (Scopus)

    Abstract

    Oxynitrides are considered as new potential candidates for photocatalysis due to their lower bandgap compared with traditional oxide photocatalysts. However, the formation of native nitrogen monovacancies during the synthesis of oxynitrides reduces their photocatalytic activity due to the vacancy-induced electron/hole recombination. This study shows that a transition from the native nitrogen monovacancies to the nitrogen-based vacancy complexes in a GaN–ZnO oxynitride not only diminishes the recombination but also enhances the photocatalytic hydrogen production. Here, the vacancy complexes are introduced by mechanical straining via the high-pressure torsion (HPT) method and it is shown that the vacancy complexes reduce the bandgap and increase the over-potential for hydrogen production on the conduction band. The current results introduce a simple but effective approach to turn the nitrogen vacancies to favorable defects for photocatalysis.

    Original languageEnglish
    Pages (from-to)149-156
    Number of pages8
    JournalActa Materialia
    Volume185
    DOIs
    Publication statusPublished - Feb 15 2020

    All Science Journal Classification (ASJC) codes

    • Electronic, Optical and Magnetic Materials
    • Ceramics and Composites
    • Polymers and Plastics
    • Metals and Alloys

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