The nickel hydroxide gold modified electrode

R. TUCCERI

Estocolmo

Congreso; European Advanced Materials Congress (EAMC 2016),; 2018

European Advanced Materials Congress (EAMC 2016),

Nickelhydroxide is an important electroactive material that, supported on differentelectrode materials, has been used for many applications of interest [1]. Simultaneouscyclic voltammetry (CV) and surface resistance (SR) measurements were employedto study the electrochemical behaviour of the nickel hydroxide-gold modifiedelectrode. SR data were interpreted in terms of the field effect and sizeeffect theories. Thefield effect theory allows one to conclude that within the potential region corresponding to hydroxide ion adsorption,77% of the electron density charge of gold is involved in the hydroxideion?gold interaction. A linearrelation between the surface resistance change (DR) and the degree of oxidation (θox)at fixed gold film thickness (fm), isobtained within the potential region corresponding to gold oxide formation. TheDR/θox slope exhibits a lineardependence on fm-2. It was observed that after the reduction of OHads and AuO layers, at potential values morenegative than -0.3 V (SCE), nickel hydroxide seems to directly interact withthe gold film surface causing an increase in the surface resistanceproportional to the nickel hydroxide surface coverage, GNi(OH)2. Compactstructures of nickel hydroxide are formed at a surface coverage value around GNi(OH)2=3 x 10-9 mol cm-2 , which is higher than the valuecorresponding to the monolayer (GNi(OH)2 = 1.06 x 10-9mol cm-2).