Catalytic ‘gelectrodes’ based on Co and Ni–Fe oxy/hydroxides for sustainable and enhanced oxygen evolution reaction

Abstract

Development of cost-effective catalysts providing low overpotentials and enhanced efficiency is a critical goal of contemporary research on electrochemical water splitting and other technologically significant processes. Translation to practical applications demands that they should also enable high current densities to be extracted. A simple strategy of encapsulating the active electrocatalyst in hydrogel polymer matrices is shown to provide a facile solution in several respects, especially regarding the last criterion. The concept is illustrated using two examples of ‘gelectrodes’ based on nanocomposites of cobalt oxyhydroxide and nickel–iron hydroxide with chitosan on nickel foam, and their efficient mediation of the oxygen evolution reaction (OER). Comparison with control systems show that significantly lower overpotentials and higher current densities with extended temporal stability can be achieved with the gelectrodes; the cobalt oxyhydroxide – chitosan and nickel-iron hydroxide – chitosan systems provide stable current densities up to 1.6–1.7 A cm⁻² for the OER with alkaline aqueous electrolyte. This simple design strategy opens up a general route to technologically useful electrocatalyst performance.