Electrocatalytic methanol oxidation using Ni–Co–graphene composite electrodes

Abstract

Exacerbation of climate change has highlighted the need for new environmentally-friendly energy sources. Fuel cells, which are devices capable of extracting electricity directly from internal chemical reactions, represent one promising concept that allows electricity generation without burning fossil fuels. Direct methanol fuel cells are one of the most popular types, and they use methanol as the fuel for electricity production. However, the current lack of suitable electrocatalytic materials limits the application of such devices on an industrial scale. This report presents a simple, one-step method for the preparation of electrocatalytic materials for methanol oxidation. The developed composite materials contain two metals (nickel and cobalt), which both exhibit catalytic properties relevant for methanol electrooxidation, and graphene, which is a carbon nanomaterial that promotes facile charge transfer and enhanced material dispersion. The tested electrodes were prepared using an electrochemical deposition process, which allowed easy control of the process conditions, such as current density, and thus easy manipulation of the final material's properties. Following this process, stable electroactive materials were prepared, and the optimal results were obtained with the electrode prepared with a current density of 3.5 A dm−2 for 15 min: this electrode had a peak current density of 15.82 mA cm−2 in 1 M KOH +1 M methanol solution.