(544gf) Tuning Cobalt and Nitrogen Co-Doped Carbon Nano Composites for Efficient Oxygen Reduction Reaction

The electrocatalytic performance and cost of ORR catalysts is crucial to many renewable energy conversion and storage systems/devices. Recently, transition metal−nitrogen doping carbon catalysts (M-N-C) have attracted tremendous attention, which is effective to reduce costs and exhibit excellent catalytic activity, but is restricted large-scale commercial applications by complex preparation processing. Rational design of fabricating highly efficient M-N-C catalysts for ORR is of great importance. Here, a novel and facile strategy to prepared Co-N-C catalyst is developed. Nano carbon composites are used to associated transition metal cobalt salt and followed pyrolysis strategy at 700-900 °C under argon atmosphere. The composites play a multiple role simultaneously, including structural support, dispersing cobalt ions by coordinate bonds, providing carbon & nitrogen source and so on. Attributed to the conductive carbon frameworks and abundant catalytic sites, the Co-N-C catalyst exhibits excellent electrocatalytic performance. A high onset potential (0.96 V vs. reversible hydrogen potential, RHE) and half-wave potential (0.80 V vs. RHE) and a large diffusion-limited current density (4.65 mA cm^−2) are achieved for ORR, comparable to or exceeding the commercial 20% Pt/C and reported M-N-C ORR electrocatalysts. This work provides a universal dispersion technology for Co-N-C catalyst that makes it a very promising candidate toward ORR.