Electrodeposited Tl2O3-Matrix Composites I. Effect of the Dispersed Phase on Nucleation and Growth of the Matrix

The electrodeposition of Formula composites has been performed by anodic oxidation of Formula ions in the presence of suspended Formula particles. This study, aimed at obtaining and characterizing new electrocatalytic materials for oxygen evolution reaction, has shown that Formula particles enhance the rate of nucleation and growth of the Formula matrix. At each potential, induction times are shorter and kinetic constants are higher in the presence of Formula than in its absence. The chronoamperometric transients measured during composite deposition are compatible with instantaneous nucleation and 3D growth. Scanning electron microscopy and energy dispersive X-ray analyses data show that particles become effectively embedded in the deposit from the early stages of its formation and act as centers of preferential growth for the matrix, so that the Formula content is higher near the electrode/composite interface than in the bulk. Formula composites are compared with other systems for which nucleation and growth of the matrix is unaffected by the dispersed phase.