ORR and OER of Co–N codoped carbon-based electrocatalysts enhanced by boundary layer oxygen molecules transfer

Two-step carbonization method was reported to synthesize Co–N doped coal tar pitch (CTP) carbon-based electrocatalysts with hierarchical pore structure , high local order degree and efficient Co-N x active structure simultaneously. The synergistic effect of the carbon substrate with highly ordered structure and the Co-N x active sites realized the “Point discharge effect”. The π-π interactions from the CTP aromatic ring sheets and Co-N x promoted the adsorption and dissociation of oxygen molecules, respectively. The increased diffusion coefficient ( D 0 ) indicated the mass transfer of oxygen molecules in the boundary layer was enhanced during the ORR process. Thanks to excellent structural characteristics, ACTP 5 @Co,N-800 exhibited better ORR performance than commercial Pt/C catalyst under alkaline conditions, and the OER activity was improved simultaneously. This work demonstrated a simple and practical strategy for the development of advanced carbon-based electrocatalysts, and also provided novel insights from kinetics perspectives for improving electrocatalytic efficiency.