PtCoNi ternary intermetallic compounds anchored on Co, Ni and N co-doped mesoporous carbon: Synergetic effect between PtCoNi nanoparticles and doped mesoporous carbon promotes the catalytic activity

Highly active and robust electrocatalysts are desired for proton exchange membrane fuel cells. Pt-based intermetallic compounds (IMCs) have been recognized as one of the most promising low-platinum catalysts for fuel cells (FCs). Herein, we report a high-performance IMCs by anchoring ordered PtCoNi ternary nanoparticles on the N, Co and Ni co-doped dodecahedral mesoporous carbon (DMC). While the introduced Co and Ni participate in the formation of PtCoNi IMCs, some of them are doped in the mesoporous carbon and coordinated by N to form Co-Ny/Ni-Nz dual active centers, which further enhances the electrocatalytic activity towards oxygen reduction reaction. Moreover, the addition of Ni results in a negative shift of the d-band center of Pt as compared to the Pt/DMC and Pt3Co/DMC, making it easier to adsorb oxygen on the surface. As expected, our optimal sample Pt3Co0.7Ni0.3/DMC exhibits excellent performance with mass activity and specific activity of 1.32 A mg−1Pt and 1.98 mA cm−2 at 0.9 V, which are 7.33 and 6.19 times that of commercial Pt/C, respectively. The Pt3Co0.7Ni0.3/DMC also reveals much better cathodic performance in an H2-air single fuel cell than commercial Pt/C catalyst with a power density of 0.802 W cm−2. This work provides critical sights into constructing efficient catalysts by ternary intermetallic strategy and synergetic effect between active components and support.