Mixed Copper/Copper-Oxide Anchored Mesoporous Fullerene Nanohybrids as Superior Electrocatalysts toward Oxygen Reduction Reaction

Developing a highly active, stable, and efficient non-noble metal-free functional electrocatalyst to supplant the benchmark Pt/C-based catalysts in practical fuel cell applications remains a stupendous challenge. A rational strategy is developed to directly anchor highly active and dispersed copper (Cu) nanospecies on mesoporous fullerenes (referred to as Cu-MFC₆₀) toward enhancing oxygen reduction reaction (ORR) electrocatalysis. The preparation of Cu-MFC₆₀ involves i) the synthesis of ordered MFC₆₀ via the prevalent nanohard templating technique and ii) the postfunctionalization of MFC₆₀ with finely distributed Cu nanospecies through incipient wet impregnation. The concurrence of Cu and cuprous oxide nanoparticles in the as-developed Cu-MFC₆₀ samples through relevant material characterizations is affirmed. The optimized ORR catalyst, Cu(15%)-MFC₆₀, exhibits superior electrocatalytic ORR characteristics with an onset potential of 0.860 vs reversible hydrogen electrode, diffusion-limiting current density (−5.183 mA cm⁻²), improved stability, and tolerance to methanol crossover along with a high selectivity (four-electron transfer). This enhanced ORR performance can be attributed to the rapid mass transfer and abundant active sites owing to the synergistic coupling effects arising from the mixed copper nanospecies and the fullerene framework.