Gasochromic effect of palladium doped peroxopolytungstic acid films prepared by the sol-gel route

B. Orel*, N. Groselj, U. O. Krasovec, M. Gabrscek, P. Bukovec, R. R. Reisfeld

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

68 Scopus citations

Abstract

Gasochromic palladium doped peroxopolytungstic acid (Pd:P-PTA) films have been prepared using dip-coating deposition from peroxopolytungstic acid (P-PTA) sols into which PdCl2 was added in molar ratios Pd:W = 1:125, 1:100, 1:53, and 1:40. These films exhibit reversible colouring/bleaching changes when exposed to hydrogen or hydrogen/argon mixture (4%) and air, alternatively. Gasochromically coloured and bleached films were characterised using in-situ Fourier transform infrared (FT-IR) spectroscopy. The vibrational modes of as-deposited, coloured and bleached films were assigned and the polaron absorption, which characterises the IR spectra of coloured films, was detected. Colouring/bleaching kinetics of films exposed to H2 and H2/Ar mixture as a function of the concentration of the catalyst and temperature of heat-treatment is reported. Proton (σpr) and electronic (σel) conductivities determined from impedance spectra revealed an increase in σel from 10-5 S cm-1 in bleached state, to 10-3 S cm-1 in coloured state, while σpr remained constant (10-2 S cm-1).

Original languageEnglish
Pages (from-to)234-245
Number of pages12
JournalSensors and Actuators, B: Chemical
Volume50 B50
Issue number3
DOIs
StatePublished - 1998
Externally publishedYes

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