Photocatalytic overall water splitting on Pt nanocluster-intercalated, restacked KCa2Nb3O10 nanosheets: the promotional effect of co-existing ions

Takayoshi Oshima; Yunan Wang; Daling Lu; Toshiyuki Yokoi; Kazuhiko Maeda

doi:10.1039/c8na00240a

Photocatalytic overall water splitting on Pt nanocluster-intercalated, restacked KCa₂Nb₃O₁₀ nanosheets: the promotional effect of co-existing ions

Nanoscale Adv. 2018 Dec 3;1(1):189-194. doi: 10.1039/c8na00240a. eCollection 2019 Jan 15.

Authors

Takayoshi Oshima^{1

2}, Yunan Wang³, Daling Lu⁴, Toshiyuki Yokoi³, Kazuhiko Maeda¹

Affiliations

¹ Department of Chemistry, School of Science, Tokyo Institute of Technology 2-12-1-NE-2, Ookayama Meguro-ku Tokyo 152-8550 Japan maedak@chem.titech.ac.jp.
² Japan Society for the Promotion of Science Kojimachi Business Center Building, 5-3-1, Kojimachi Chiyoda-ku Tokyo 102-0083 Japan.
³ Nanospace Catalysis Unit, Institute of Innovative Research, Tokyo Institute of Technology 4259-S2-5, Nagatsuta, Midori-ku Yokohama 226-8503 Japan.
⁴ Center for Advanced Materials Analysis, Tokyo Institute of Technology 4259-R1-34, Nagatsuta-cho, Midori-ku Yokohama 226-850 Japan.

Abstract

Promotional effects of co-existing ions on overall water splitting into H₂ and O₂ have been studied in bulk-type semiconductor photocatalysts (e.g., TiO₂), but such an effect remains unexplored in two-dimensional nanosheet photocatalysts. Here we examined the effect of co-existing ions on the photocatalytic water splitting activity of Pt nanocluster-intercalated KCa₂Nb₃O₁₀ nanosheets. Interestingly, not only anions, as usually observed in bulk-type photocatalysts, but also cations had a significant influence on the photocatalytic performance. The rates of H₂ and O₂ evolution over Pt/KCa₂Nb₃O₁₀ as well as the product stoichiometry were improved in the presence of NaI. I^- ions were found to effectively suppress undesirable backward reactions, consistent with the previous work by Abe et al. (Chem. Phys. Lett., 2003, 371, 360-364). On the other hand, Na⁺ ions in the reaction solution were exchanged for K⁺ in the interlayer space of KCa₂Nb₃O₁₀ during the water splitting reaction, which promoted interlayer hydration and consequently improved photocatalytic performance.