Co-N as a Promoter towards Modulation Surface Chemistry of PtCo Alloy on 2D Thin Layer Hierarchical Porous Nitrogen-Carbon for the Efficient Oxygen Reduction Reaction

摘要

To clarify the mechanism of active site conversion and utilization of the PtM alloy complexed with nitrogen-doped carbon (NC) catalysts (PtM/NC) for oxygen reduction reaction (ORR), we synthesized the two-dimensions thin-layer hierarchical porous nitrogen-carbon for supporting PtCo nanoparticles (2D PtCo/TNC) and applied to alkaline ORR. The self-assembled thin layer of carbon nitride (TL-C3N4) was thermally fused with commercial carbon black (C) to form a 2D-TNC, which can conduct the optimal mass transfer. Therewith, PtCo nano- particles were anchored on this carrier through a thermal injection strategy, promoting the formation of CoN and achieving low Pt loading (2wt%). As a promoter, the CoN favours the lattice distortion of PtCo alloys and facilitates the in-situ adsorption-diffusion process of oxygen-containing species. Thus, the obtained catalyst demonstrates an excellent ORR activity in alkaline electrolytes, with a half-wave potential (E_(1/2)) of 0.885 V and electrochemical active surface area (ECSA) of 111 m~2/g, lower Tafel slope of 66 mV/dec.