A Mechanistic Study of Oxygen Evolution on Li‐Doped Co3 O 4

Oxygen evolution studies were carried out on preanodized Teflon‐bonded and Li‐doped electrodes in medium. The oxygen evolution performance was found to increase with increase in Li doping. The results suggest the Co 3+ ions are the major active sites for oxygen evolution. Steady‐state current‐potential measurements gave a Tafel slope of ∼60 mV per decade on all the oxides. This Tafel parameter was confirmed by potentiostatic transient measurement. A mechanistic sequence for oxygen evolution has been put forward where T is trivalent cobalt and M is divalent or trivalent cobalt. The proton abstraction step is rate determining. This is supported by experimental reaction order parameters. These studies enabled the development of an efficient oxygen evolution electrocatalyst. Teflon bonded, preanodized, 10 a/o Li‐doped electrode was found to be 1.52V vs. the dynamic hydrogen electrode (DHE) at a current density of 1A cm −2 in in 70°C. Laboratory durability tests carried out on these electrodes under practical conditions showed good stability of structure and performance for 5800 h.