Optimising CNF-supported cobalt catalysts for enhanced oxygen evolution reaction activity through plasma modification

Transition metal–carbon composite materials constitute a very robust class of materials that can meet the alkaline OER demands. Cobalt spinel exhibits good OER activity and stability among the transition metal compounds. On the other hand, carbon nanofibers (CNF), characterised by high oxidation resistance, surface area and electrical conductivity, appear to be a natural choice for a metal oxide active phase support. In this study, we used a low-temperature plasma for a facile surface functionalisation with oxygen groups to boost the OER activity of the cobalt phase. The cobalt phase’s dispersion was the most critical factor in obtaining the best OER activity of the CNF-supported cobalt electrocatalysts. The deposition of the cobalt phase on the CNF improves the stability of the catalytic system compared to the unsupported cobalt spinel by protecting the electrode and polymer film from extensive oxidative degradation.