ELECTRODEPOSITED TL2O3-MATRIX COMPOSITES II - ELECTROCATALYSIS OF OXYGEN EVOLUTION REACTION ON TL2O3 CO3O4 COMPOSITES/

The dependence of composition and morphology of Tl2O3/Co3O4 composites on the experimental variables chosen for their anodic deposition (i.e ., concentration of Co3O4 particles in suspension, electrode potential , electrolysis charge, and angular speed of the electrode) has been in vestigated. The composite layers have been tested as electrode materia ls for oxygen evolution from basic media, and found to be rather effec tive electrocatalysts characterized by the following features: overpot ential (eta) at j = 100 mA cm(-2) ca. 475 mV, Tafel slope close to 60 mV decade(-1), linear dependence of j on [OH-]. Significant electrocat alytic activity could be achieved with a Co3O4 loading as low as 2.10( -5) g cm(-2). The electrode performance was maintained during a 14 day electrolysis carried out at room temperature with j = 100 mA cm(-2). Partial reduction of the composite layer was found to activate the com posite electrodes, by decreasing eta to ca. 415 mV (at j = 100 mA cm(- 2)). However this activation was not long lasting.