Electrodeposited composite electrode materials: effect of the concentration of the electrocatalytic dispersed phase on the electrode activity

PbO2 + Co3O4, Tl2O3 + Co3O4 and Ni + Co3O4 composite layers have been obtai ned by either anodic (oxide matrices) or cathodic (Ni-matrix) electrodeposi tion. Their electrocatalytic activity in the oxygen evolution reaction has been investigated with the aim of assessing the effect of concentration of Co3O4 and surface roughness. Different composites showed a different depend ence of oxygen evolution current density on Co3O4 content. Only in the case of PbO2 + Co3O4, the electrode effective area appeared to increase with th e dispersed phase concentration, resulting in a non-linear relationship bet ween oxygen evolution rate and Co3O4 content. (C) 1999 Elsevier Science Ltd . All rights reserved.