Constructing ultrafine Pt nanoparticles anchored on N-doped porous carbon nanofibers for efficient and stable oxygen reduction reaction

Synthesis of ultrafine Pt nanoparticles with high metal utilization is essential to achieve efficient oxygen reduction reaction (ORR) with a low mass loading of Pt; however, it remains challenging. Here, we propose a facile yet robust strategy to construct ultrafine Pt nanoparticles (similar to 3 nm) anchored on porous carbon nanofibers (PCNFs) via electro-spinning. It is found that the porous architecture facilitates mass transport and active sites exposure, thereby providing highly accessible Pt sites. As a result, the synthesized Pt@PCNFs with low Pt loading (4.2 wt%) display excellent ORR activity with a mass activity of 41 and 51 A g(Pt)(-1) at 0.9 V in alkaline and acidic electrolytes, 8 times and 10 times that of the corresponding value for commercial Pt/C catalyst, respectively. More importantly, the strong metal-support interaction between Pt nanoparticles and N-doped carbon nanofibers, as well as carbon shell protection, significantly enhances the stability by suppressing the aggregation of Pt nanoparticles during ORR, and consequently the stability of Pt@PCNFs is much superior to that of the Pt/C benchmark in both alkaline and acid media at different temperatures. This work provides a facile approach to developing efficient and stable low-Pt-based electrocatalysts toward ORR.