Cobalt nanorods decorated titanium oxide arrays as efficient and stable electrocatalyst for oxygen evolution reaction

Oxygen evolution reaction (OER) is a key process in many electrochemical energy conversion technologies, such as water electrolysis and zinc-air batteries. However, the efficiency of these electrocatalysis processes is usually hindered by the slow OER kinetics. Meanwhile, the oxidative reaction condition of OER also poses a great challenge for the long-term stability of OER catalysts. In this work, through anodic oxidation, hydrothermal reaction and calcination, a self-supported, efficient and stable OER catalyst (Co@TiO 2 /Ti) was developed by loading Co nanoparticles on TiO 2 nanotube array rooted on Ti foil. The TiO 2 array substrate not only offers good corrosion resistance under the strong oxidative reaction condition of OER, but also provides an increased surface area for depositing the catalytic active Co-based catalysts. As a result, the Co@TiO 2 /Ti catalyst shows excellent OER activity exhibiting an overpotential of 382 mV (j=50 mA cm −2 ) and onset potential of 1.46 V vs. RHE in 1M KOH solution. Importantly, it also achieves a high stability at high current density operating condition. In addition, post-OER reaction characterizations show that the Co nanoparticles were oxidized into Co 3 O 4 crystals, suggesting that the latter was the real component in catalyzing OER reaction. The self-supported efficient and stable catalyst and the insights revealed in the real OER catalysis phase advanced the development of OER catalysts.