Charge transfer at oxygen/zirconia interface at elevated temperatures: Part 5: Reactivity models

Abstract

Measurements of work function using the Kelvin method are based on determination of the contact potential difference (CPD) between the studied specimen and a reference electrode, typically Pt. The present work considers the physical meaning of the CPD, which is formed between the surfaces of a metal oxide and Pt in the presence of oxygen at elevated temperatures. The focus is on the reactivity of both metal oxide and Pt with oxygen and the associated electrical effects. The reactivity at the oxygen/zirconia interface is considered in terms of oxygen chemisorption, resulting in the formation of singly ionised molecular and atomic species, and oxygen incorporation into the zirconia lattice. The reactivity at the O₂/Pt interface is considered in terms of oxygen incorporation into PtO₂, which forms a thin layer covering the Pt. The derived reactivity models are used for quantitative assessment of CPD changes in terms of work function changes of yttria-stabilised zirconia (YSZ) during oxidation and reduction.

Keywords

CONTACT POTENTIAL DIFFERENCE KELVIN PROBE OXYGEN CHEMISORPTION PLATINUM WORK FUNCTION YTTRIA-STABILISED ZIRCONIA

References

Nowotny

: in ‘CRC handbook of solid state electrochemistry’, (ed. Gellings

P. J.

and Bouwmeester

H. J. M.

), 121–159; 1997, Boca Raton, FL, CRC Press.

Bak

, Nowotny

and Sorrell

C. C.

: in ‘Electrical properties of oxide materials’, (ed. Nowotny

), 1–80; 1997, Zurich, TransTech Publications.

Nowotny

, Bak

and Sorrell

C. C.

: Adv. AppL Ceram., 2005, 104, 174–180 (Part 4).

Kleitz

, Fabry

, Foultier

and Schouler

: in ‘Transport in nonstoichiometric compounds’, (ed. Nowotny

), 481–502; 1982, Amsterdam, Elsevier.

Lord Kelvin:

Rev. Set Instrum., 1932, 3, 367–372.

Wagner

: personal communication to J. Nowotny, 2 June 1977.

Kofstad

: Nonstoichiometry, electrical conductivity and diffu-sion in binary metal oxides‘, 1972, New York, NY, Wiley.

Nowotny

, Bak

, Nowotny

M. K.

and Sorrell

C. C.

: Adv. Appl. Ceram., 2005, 104, 165–173 (Part 3).

Nowotny

, Bak

, Nowotny

M. K.

and Sorrell

C. C.

: Adv. Appl. Ceram., 2005, 104, 154–164 (Part 2).

10.

Bak

, Nowotny

, Rekas

and Sorrell

C. C.

: in ‘Ceramic interfaces’, (ed. Uematsu

and Yokokawa

), 151–178; 2003, Zurich, TransTech Publications.

11.

Nowotny

and Sloma

: in ‘Surface and near-surface chemistry of oxide materials’, (ed. Nowotny

and Dufour

L.-C.

), 281–343; 1988, Amsterdam, Elsevier.

12.

Bielanski

and Haber

: CataL Rev. Set Eng., 1979, 19, 1–41.

13.

Vohrer

, Wiemhofer

H.-D.

, Gopel

, Van Hassel

B. A.

and Burggraaf

A. J.

: Solid State Ionics, 1993, 59, 141–149.

14.

Smith

: J. Electrochem. Soc., 1964, 111, 1020–1034.

15.

Chrusciel

, Deren

and Nowotny

: Exp. Tech. Phys., 1966, 14, 127–133.

16.

De Bruin

H. J.

: Nature, 1978, 272, 712–713.

17.

De Bruin

H. J.

: Silic. Ind, 1977, 11, 439–444.

18.

Besocke

and Berger

: Rev. Set Instrum., 1976, 47, 840–842.

19.

Nowotny

: J. Chim. Phys. Fr., 1978, 75, 689–697.

20.

Drevet

, Henault

and Foultier

: Solid State Ionics, 2000, 136/7, 807–812.

21.

Kuzin

and Bronin

: Solid State Ionics, 2000, 136/7, 45–50.

22.

Bonzel

H. P.

, Franken

A. M.

and Pirug

: Surf Set, 1981, 104, 625–631.

23.

Niehus

and Comsa

: Surf Set, 1981, 102, 114–121.

24.

Akheter

, Greenlief

C. M.

, Chen

H. W.

and White

J. M.

: Appl. Surf Set, 1986, 25, 154–160.

25.

Derry

G. N.

and Ross

P. N.

: J. Chem. Phys., 1985, 82, 2772–2779.

26.

Zhang

and Henrich

V. E.

: Surf Set, 1992, 277, 263–272.

27.

Bak

, Rekas

, Nowotny

, Sorrell

C. C.

, Adamski

, Dyrek

and Sojka

: Int. J. Ionics, 2001, 7, 332–338.

28.

Ikuma

, Komatsu

and Komatsu

: Adv. Ceram., 1988, 24, 749–758.

29.

Bak

, Nowotny

, Rekas

and Sorrell

C. C.

: Solid State Ionics, 1999, 117, 157–160.

30.

Nowotny

, Bak

and Sorrell

C. C.

: Adv. Appl. Ceram., 2005, 104, 195–199 (Part 7).