The electrodeposition of Au particles on the surface of glass carbon (GC) electrode modified with polyaniline (PAni) and the electrocatalytic activity for the oxidation of formaldehyde were investigated by cyclic voltammetry and potentiostatic step. The results show that at initial stages the electrocrystallization of Au on PAni/GC followed the mechanism of instantaneous three dimensional nucleation and diffusion-controlled growth. The electrode prepared by constant current electrodeposition has higher catalytic current than that prepared by cyclic voltammetric electrodeposition for formaldehyde oxidation in alkaline media while the latter has more negative electrocatalytic potential in the oxidation of formaldehyde.

Key words: ELECTRO-DEPOSITION, GOLD, FORMALDEHYDE, ELECTRO-CATALYSIS, CYCLOVOLTAMGRAPH, ANILINE, CHEMICAL MODIFIED ELECTRODE