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Optical readout of hydrogen storage in films of Au and Pd

2017; Optica Publishing Group; Volume: 25; Issue: 20 Linguagem: Inglês

10.1364/oe.25.024081

1094-4087

Yoshiaki Nishijima, Shogo Shimizu, Keisuke Kurihara, Yoshikazu Hashimoto, Hajime Takahashi, Armandas Balčytis, Gediminas Seniutinas, Shinji Okazaki, Jurga Juodkazytė, Takeshi Iwasa, Tetsuya Taketsugu, Yoriko Tominaga, Saulius Juodkazis,

Electrocatalysts for Energy Conversion

For hydrogen sensor and storage applications, films of Au and Pd were (i) co-sputtered at different rates or (ii) deposited in a sequentially alternating fashion to create a layered structure on a cover glass. Peculiarities of hydrogen uptake and release were optically monitored using 1.3 μm wavelength light. Increase of optical transmission was observed for hydrogenated Pd-rich films of 10-30 nm thickness. Up to a three times slower hydrogen release took place as compared with the hydrogen uptake. Compositional ratio of Au:Pd and thermal treatment of films provided control over the optical extinction changes and hydrogen uptake/release time constants. Higher uptake and release rates were observed in the annealed Au:Pd films as compared to those deposited at room temperature and were faster for the Auricher films. Three main parameters relevant for sensors: sensitivity, selectivity, stability (reproducibility) are discussed together with the hydrogenation mechanism in Au:Pd alloys.