Abundant nanotube coated ordered macroporous carbon matrix with enhanced electrocatalytic activity

Abstract Exploiting non-noble metal bifunctional electrocatalysts for efficient oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is a feasible approach for developing clean energy. Herein, we synthesize a transition metal coordinating nitrogen (Fe/Ni-N) doped carbon material (FeNi-MNC) with unique morphology combining external diverging carbon nanotubes and internal carbon matrix with ordered macropore alignments. With the co-catalysis of Fe and Ni species and the space limiting of SiO2 template in carbonation, the obtained FeNi-MNC shows high Fe/Ni-N contents. Profiting from the hierarchical morphology and abundant active sites, the catalyst exhibits excellent activity for ORR in 0.1 M KOH with a half-wave potential of 0.834 V and a Tafel slope of 53.1 mv dec−1 being superior to Pt/C. Moreover, it only needs an overpotential of 298 mV reaching 10 mA cm−2 for OER in 1.0 M KOH. Our work constructs a 3-dimensional porous carbon matrix integrated with 1-dimensional carbon nanotubes and 2-dimensional carbon nanosheets to enhance the catalytic performance.