Ni and Co-based bifunctional electrocatalysts supported on TiO2@C for oxygen evolution and reduction reactions

Abstract

In the search for affordable, ecofriendly, and sustainable catalysts for energy-related processes, series of Ni and Co-based bifunctional hybrid electrocatalysts supported on TiO2@C were prepared and studied in the oxygen evolution (OER) and oxygen reduction reactions (ORR). The hybrid TiO2@C supports were prepared using three biomass precursors: furfural, chitosan and saccharose. The nature and dispersion of the metallic phases on those supports was evaluated as a function of the biomass-derived precursors. The prepared materials showed electrocatalytic activity towards ORR and OER reaction, being more active for the latter. Despite a lower performance than Pt/C benchmark, these materials are clearly at much lower costs. The long-term stability and performance of the catalysts were also performed. The number of electrons involved in both processes was determined and a mechanism is proposed for the understanding of the mechanism of reactions using the present materials. It can be concluded that the Ni and mainly Co-based electrocatalysts show a remarkable potential for use as alternative catalysts in fuel cells-related reactions.