Preparation of Stable Silver Nanoparticles Having Wide Red-To-Near-Infrared Extinction

Shiori Kawamura; Kazuki Matsubara; Sotaro Sakai; Kazuhisa Sasaki; Masataro Saito; Kenji Saito; Masayuki Yagi; Wataru Norimatsu; Ryo Sasai; Michiko Kusunoki; Miharu Eguchi; Shu Yin; Yusuke Asakura; Tatsuto Yui

doi:10.1002/gch2.201700105

Preparation of Stable Silver Nanoparticles Having Wide Red-To-Near-Infrared Extinction

Glob Chall. 2018 Feb 21;2(3):1700105. doi: 10.1002/gch2.201700105. eCollection 2018 Mar 9.

Authors

Affiliations

¹ Department of Materials Science and Technology Faculty of Engineering Niigata University 8050 Ikarashi-2 Niigata 950-2181 Japan.
² Department of Materials Chemistry Graduate School of Engineering Nagoya University Furo-cho, Chikusa-ku Nagoya-shi Aichi-ken 464-8603 Japan.
³ Department of Physics and Materials Science Interdisciplinary Graduate School of Science and Engineering Shimane University 1060, Nishi-kawatsu-cho Matsue 690-8504 Japan.
⁴ Institute of Materials and Systems for Sustainability Nagoya University Furo-cho, Chikusa-ku Nagoya-shi Aichi-ken 464-8603 Japan.
⁵ Electronic Functional Materials Group Polymer Materials Unit National Institute for Materials Science (NIMS) 1-1 Namiki Tsukuba Ibaraki 305-0044 Japan.
⁶ Institute of Multidisciplinary Research for Advanced Materials Tohoku University 2-1-1, Katahira Aoba-ku Sendai 980-8577 Japan.

Abstract

The synthesis of silver nanoparticles (AgNPs) within the interlayer space of transparent layered titania nanosheet (TNS) films is investigated. A considerable number of silver ions (≈70% against the cation exchange capacity of the TNS) are intercalated in the TNS films using methyl-viologen-containing TNSs as a precursor. The silver ion (Ag⁺)-containing TNS films are treated with aqueous sodium tetrahydroborate (NaBH₄), resulting in a gradual color change to bright blue. Various structural analyses clearly show that crystalline AgNPs are generated within the interlayer space of the TNSs. The NaBH₄-treated films show intense and characteristic near-infrared (NIR) extinction spectra up to 1800 nm. The stability of the AgNPs within the TNS against oxygen and moisture is also investigated, and 96% and 82% of the AgNPs remain after standing in air for 1 month and 1 year, respectively. The NIR extinctions of the AgNP-containing TNS films are further extended by employing different preparation procedures, for example, using sintered TNS films as starting materials and irradiating the Ag⁺-containing TNSs with ultraviolet (UV) light. The obtained AgNP-containing TNS films exhibit photochemical activities in the production of hydrogen from ammonia borane under visible-light irradiation and the decomposition of nitrogen monoxide under UV-light irradiation.

Keywords: catalysts; layered materials; layered semiconductors; metal nanoparticles; near‐infrared.