Highly porous Ti-Ni anodes for electrochemical oxidations

Abstract

The hydrogen rising economy is demanding an active and durable electrocatalysts based on low-cost, earth abundant materials for water electrolysis. Oxygen electrochemistry plays a key role in renewable energy technologies, but the slow kinetics of oxygen evolution reaction limit the performance and commercialization such as devices. Nonetheless, most of the previous work has been focus on precious metals and there are no guidelines for the choice of oxides as evolving oxygen electrodes. Up to now, iridium dioxide and ruthenium dioxide are the state-of-theart oxygen evolution reaction electrocatalysts with low overpotential and Tafel slope. This work describes a general method to obtain highly porous electrodes and their use as dimensionally stable anodes for the O2 evolution reaction (OER). By using a powder metallurgy based process, where metallic titanium and nickel powders are pressed and thermally treated, we obtain electrodes that benefit from a 1000-fold increase in the electrochemical surface area (ECSA). In addition, active catalytic species for water oxidation (i.e. NiOOH) are generated during the processing converting these electrodes as ideal candidates for evaluation in oxidation reactions. Excellent OER performance is obtained with overpotentials below 270 mV at 10 mA cm−2, exceeding those of commercially available alternatives. The current work paves the way for a generic method that will be extended to other electrochemical reactions.