Cobalt Hydroxide Modification of TiO2 Nanosheets for Visible-Light-Responsive Photocatalysts

Hidehisa Hagiwara; Katsuaki Hayakawa; Kazuki Ishitsuka; Keisuke Awaya; Kazuto Hatakeyama; Shintaro Ida

doi:10.1021/acsomega.4c10161

Cobalt Hydroxide Modification of TiO₂ Nanosheets for Visible-Light-Responsive Photocatalysts

Hidehisa Hagiwara^*, Katsuaki Hayakawa, Kazuki Ishitsuka, Keisuke Awaya, Kazuto Hatakeyama, Shintaro Ida

^*Corresponding author for this work

Hydrogen Isotope Research Center, Organization for Promotion of Research

Research output: Contribution to journal › Article › peer-review

Abstract

To make full use of sunlight for water splitting reactions for hydrogen production, a visible-light-driven photocatalyst was developed by modifying TiO₂ nanosheets with Co(OH)₂. By adding an aqueous Co(NO₃)₂·6H₂O solution to a TiO₂ nanosheet suspension, the TiO₂ nanosheets aggregated and Co(OH)₂ was formed. In the ultraviolet-visible (UV-vis) diffuse reflectance spectrum of the photocatalyst, new absorption bands attributable to Co(OH)₂ and the interfacial charge transfer between Co(OH)₂ and the TiO₂ nanosheets appeared at around 600 and 400 nm, respectively. The photocatalytic activity of Co(OH)₂/TiO₂ nanosheets was evaluated in terms of the O₂ evolution reaction in an aqueous AgNO₃ solution, finding that the reaction proceeds under visible light. Furthermore, the investigation of the wavelength dependence of the photocatalytic activity revealed that the photocatalytic reaction on Co(OH)₂/TiO₂ nanosheets proceeds via Co(OH)₂ photocatalysis and interfacial charge transfer between Co(OH)₂ and the TiO₂ nanosheets under visible light irradiation.

Original language	English
Pages (from-to)	3101-3107
Number of pages	7
Journal	ACS Omega
Volume	10
Issue number	3
DOIs	https://doi.org/10.1021/acsomega.4c10161
State	Published - 2025/01/28

ASJC Scopus subject areas

General Chemistry
General Chemical Engineering

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This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1021/acsomega.4c10161

Cite this

@article{cc2fc3895d9147b68720eba9590f74d8,

title = "Cobalt Hydroxide Modification of TiO2 Nanosheets for Visible-Light-Responsive Photocatalysts",

abstract = "To make full use of sunlight for water splitting reactions for hydrogen production, a visible-light-driven photocatalyst was developed by modifying TiO2 nanosheets with Co(OH)2. By adding an aqueous Co(NO3)2·6H2O solution to a TiO2 nanosheet suspension, the TiO2 nanosheets aggregated and Co(OH)2 was formed. In the ultraviolet-visible (UV-vis) diffuse reflectance spectrum of the photocatalyst, new absorption bands attributable to Co(OH)2 and the interfacial charge transfer between Co(OH)2 and the TiO2 nanosheets appeared at around 600 and 400 nm, respectively. The photocatalytic activity of Co(OH)2/TiO2 nanosheets was evaluated in terms of the O2 evolution reaction in an aqueous AgNO3 solution, finding that the reaction proceeds under visible light. Furthermore, the investigation of the wavelength dependence of the photocatalytic activity revealed that the photocatalytic reaction on Co(OH)2/TiO2 nanosheets proceeds via Co(OH)2 photocatalysis and interfacial charge transfer between Co(OH)2 and the TiO2 nanosheets under visible light irradiation.",

author = "Hidehisa Hagiwara and Katsuaki Hayakawa and Kazuki Ishitsuka and Keisuke Awaya and Kazuto Hatakeyama and Shintaro Ida",

note = "Publisher Copyright: {\textcopyright} 2025 The Authors. Published by American Chemical Society.",

year = "2025",

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doi = "10.1021/acsomega.4c10161",

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T1 - Cobalt Hydroxide Modification of TiO2 Nanosheets for Visible-Light-Responsive Photocatalysts

AU - Hagiwara, Hidehisa

AU - Hayakawa, Katsuaki

AU - Ishitsuka, Kazuki

AU - Awaya, Keisuke

AU - Hatakeyama, Kazuto

AU - Ida, Shintaro

PY - 2025/1/28

Y1 - 2025/1/28

N2 - To make full use of sunlight for water splitting reactions for hydrogen production, a visible-light-driven photocatalyst was developed by modifying TiO2 nanosheets with Co(OH)2. By adding an aqueous Co(NO3)2·6H2O solution to a TiO2 nanosheet suspension, the TiO2 nanosheets aggregated and Co(OH)2 was formed. In the ultraviolet-visible (UV-vis) diffuse reflectance spectrum of the photocatalyst, new absorption bands attributable to Co(OH)2 and the interfacial charge transfer between Co(OH)2 and the TiO2 nanosheets appeared at around 600 and 400 nm, respectively. The photocatalytic activity of Co(OH)2/TiO2 nanosheets was evaluated in terms of the O2 evolution reaction in an aqueous AgNO3 solution, finding that the reaction proceeds under visible light. Furthermore, the investigation of the wavelength dependence of the photocatalytic activity revealed that the photocatalytic reaction on Co(OH)2/TiO2 nanosheets proceeds via Co(OH)2 photocatalysis and interfacial charge transfer between Co(OH)2 and the TiO2 nanosheets under visible light irradiation.

AB - To make full use of sunlight for water splitting reactions for hydrogen production, a visible-light-driven photocatalyst was developed by modifying TiO2 nanosheets with Co(OH)2. By adding an aqueous Co(NO3)2·6H2O solution to a TiO2 nanosheet suspension, the TiO2 nanosheets aggregated and Co(OH)2 was formed. In the ultraviolet-visible (UV-vis) diffuse reflectance spectrum of the photocatalyst, new absorption bands attributable to Co(OH)2 and the interfacial charge transfer between Co(OH)2 and the TiO2 nanosheets appeared at around 600 and 400 nm, respectively. The photocatalytic activity of Co(OH)2/TiO2 nanosheets was evaluated in terms of the O2 evolution reaction in an aqueous AgNO3 solution, finding that the reaction proceeds under visible light. Furthermore, the investigation of the wavelength dependence of the photocatalytic activity revealed that the photocatalytic reaction on Co(OH)2/TiO2 nanosheets proceeds via Co(OH)2 photocatalysis and interfacial charge transfer between Co(OH)2 and the TiO2 nanosheets under visible light irradiation.

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