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

Abstract

To clarify the mechanism of active site conversion and utilization of the Pt−M alloy complexed with nitrogen‐doped carbon (NC) catalysts (Pt−M/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 nanoparticles were anchored on this carrier through a thermal injection strategy, promoting the formation of Co−N and achieving low Pt loading (2 wt%). As a promoter, the Co−N 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 (E1/2) of 0.885 V and electrochemical active surface area (ECSA) of 111 m2/g, lower Tafel slope of 66 mV/dec.

Highly dispersed ultrafine PtCo alloy nanoparticles on unique composite carbon supports for proton exchange membrane fuel cells

“…As demonstrated in Fig. 1e, the characteristic diffraction peaks of the samples in the XRD pattern matched well with those of CoPt 3 (standard PDF: 00-029-0049), translating to the Pt : Co atomic ratio of 3 : 1 con- 22 Meanwhile, the graphitization degree of the carbon support can also impact the lifetime of the fuel cell. Thus, the composite supports facilitate the loading and stabilization of Pt nanoparticles, forming smaller and more uniform PtCo nanoparticles than PtCoKB (Fig.…”

“…Moreover, compared to commercial Pt/C, an obvious diffraction peak shift was observed at 40.4°, which verifies the generation of shrinkage strain in the PtCo alloy, known for decreasing the Pt usage and enhancing the ORR intrinsic activity. 22 Meanwhile, the graphitization degree of the carbon support can also impact the lifetime of the fuel cell. Thus, the composite supports facilitate the loading and stabilization of Pt nanoparticles, forming smaller and more uniform PtCo nanoparticles than PtCoKB (Fig.…”