Electrochemical Determination of the Small Hydrogen Decomposition Pressures in HxMoO3

Abstract

AbstractIn analogy to the O2 solid electrolyte probe a proton conducting membrane (Nafion®) was used in an electrochemical cell for the determination of the small H2 decomposition pressures of the bronze phases of MoO3 (HxMoO3): 4.8 · 10−15 Pa for 0 < x < 0.23, 6.3 · 10−9 Pa for 0.40 < x < 0.85 and 1.1 · 10−2 Pa for 1.04 < x < 1.55. – Potential control at the gas electrode is even possible during small current flows, so that diffusion coefficients (D) could be obtained by analysing the potentiostatic oxidation of single phased samples: (2.5 ± 1.0) · 10−8 cm2 s−1 for x = 0.23, (2.4 ± 1.6) · 10−6 cm2 s−1 for x = 0.85 and (1.6 ± 0.9) · 10−8 cm2 s−1 for x = 1.55.