posted on 2024-01-16, 17:33authored byLihua Lin, Mamiko Nakabayashi, Daling Lu, Takashi Hisatomi, Tsuyoshi Takata, Kazunari Domen
Y2Ti2O5S2 (YTOS) is
a stable oxysulfide photocatalyst applicable to water splitting under
visible light with wavelengths of up to 650 nm. However, the activity
of YTOS in the overall water-splitting reaction is still low, possibly
because YTOS particles prepared by a solid-state reaction (SSR) method
have large sizes and high defect density. Therefore, understanding
the formation mechanism is indispensable for synthesizing YTOS with
the desired physical properties to improve its performance. In this
study, we investigated the formation mechanism for YTOS produced by
an SSR method. The results indicated that Y2Ti2O7, Y2O2S, and TiS2 are
key intermediate phases in the formation of YTOS. Detailed formation
steps are proposed for YTOS particles as they pass through these intermediate
phases. By controlling the formation process for these intermediates,
it was possible to prepare YTOS with a reduced particle size and enhanced
activity for photocatalytic H2 evolution.