Electrochemical investigations of polycrystalline H{sub x}Nb{sub 2}O{sub 5}

Journal Article · Wed Feb 15 04:00:00 EST 1995 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1006/jssc.1995.1130· OSTI ID:508684

Schwitzgebel, G; Unruh, T ^[1]

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1. Unviersitaet des Saarlandes, Saarbruecken (Germany)

Polycrystalline samples of H{sub x}Nb{sub 2}O{sub 5} were prepared by electrochemical reduction of pressed and sintered powder samples of the H-Nb{sub 2}O{sub 5} modification. The hydrogen content of the bronze was determined by redox titration. The electrode potential showed that the bronze is thermodynamically unstable with respect to decomposition into Nb{sub 2}O{sub 5} and gaseous hydrogen. The hydrogen loss obeys a second-order rate law. The electrode potential fulfills Nernst`s law with a square dependence on the hydrogen content. The specific resistance of H{sub 0.18}Nb{sub 2}O{sub 5} determined by four-point dc measurements amounts to {rho}(30{degrees}C) = (0.0110 {+-} 0.0015) {Omega} cm. The protonic conductivity of the bronze was substantiated by polarization experiments and the diffusion coefficient of H{sup {circ}} (D {approx} 5 x 10{sup -9} cm{sup 2}/sec) was estimated from the rate law of the depolarization voltage.

• OSTI ID: 508684
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 1 Vol. 115; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
40 CHEMISTRY
CHEMICAL REACTION KINETICS
ELECTROCHEMISTRY
IONIC CONDUCTIVITY
NIOBIUM HYDRIDES
NIOBIUM OXIDES
REDUCTION
STOICHIOMETRY
TITRATION