A synergistic effect of Co and CeO₂ in nitrogen-doped carbon nanostructure for the enhanced oxygen electrode activity and stability

The development of efficient and durable non-precious cathode catalyst have been received the great interest to replace the commercial noble catalysts, thereby minimizing the overall cost of polymer electrolyte membrane fuel cells. We describe the synthesis of self-redox CeO₂ supported Co in nitrogen-doped carbon nanorods (Co-CeO₂/N-CNR) by the electro-spun method, and introduced as an enhanced bifunctional catalyst for oxygen reduction (ORR) as well as evolution (OER) reactions by the synergistic effect of oxygen buffer CeO₂ with metallic Co. Systematic structural and optical studies confirm the formation and uniform distribution of CeO₂ and Co particles in N-CNR. The X-ray photoelectron spectroscopy analysis of Co-CeO₂/N-CNR reveals that the presence of Co²⁺ and multiple valence states of ceria (Ce⁴⁺ and Ce³⁺). The shift in binding energies of Co²⁺ and Ce³⁺ states confirm the possible interaction for the cooperative effect of ceria and cobalt during ORR and OER, and electrode stability improvement as well. The Co-CeO₂/N-CNR catalyst shows the enhanced oxygen electrode potential of 0.84 V (versus reversible hydrogen electrode), which is 100 and 196 mV lower than Co/N-CNR and Pt/C, respectively, including the improved stability.