Unveiling a synthetic strategy for a cerium-based hetero-phase hybrid electrocatalyst for near-zero peroxide yield in the ORR

Abstract

The urgent need to replace precious metal electrocatalysts with platinum-group-metal-free (PGM-free) alternatives without sacrificing activity and stability for fuel cell applications drives the current research. This study presents the development of a highly efficient hybrid catalyst, CeCNC_F, utilising a simple one-pot synthetic approach comprising polyaniline, cerium, and carbon nanofibers to optimise energy-efficient technologies. The CeCNC_F catalyst demonstrates an onset potential of 0.86 V vs. RHE, closely matching that of the commercial Pt/C catalyst, and exhibits an equivalent limiting current density of 5.21 mA cm⁻², which is comparable to that of Pt/C. This indicates superior oxygen diffusion and a higher density of catalytic active sites. The reaction proceeds via a four-electron direct pathway with a minimal peroxide yield of 0.06%, highlighting its highly efficient reaction kinetics. Additionally, the catalyst shows significant resistance to methanol crossover and maintains stability up to 3000 cycles. Its notable performance is attributed to the nitrogen-dispersed carbon framework, oxygen-vacancy-fortified Ce species, and increased surface area, which collectively intensify the exposure of the active sites to reactant species. This research offers a cost-effective approach for synthesising PGM-free electrocatalysts, providing a promising high-performance cathode material for practical applications.