Space-confined catalyst design toward ultrafine Pt nanoparticles with enhanced oxygen reduction activity and durability

Abstract

Carbon supported platinum nanoparticles have been widely used to catalyze oxygen reduction reaction (ORR), however, their real-world applications in polymer electrolyte membrane fuel cells (PEMFCs) is mainly bottlenecked by insufficient catalytic activity and durability due to particles agglomeration and dissociation from support material. Herein, we have developed a facile catalyst design to embed ultrafine Pt nanoparticles inside the nanopores of carbon support towards increased Pt atom utilization and suppressed Ostwald ripening through space-confinement effect. Besides, the novel strategy endows the resultant Pt nanoparticles with an optimized electronic structure, which further accelerates ORR kinetics. Due to these attributes, the as-prepared Pt nanoparticle inside pore (Ptinside/KJ600) catalyst have shown remarkable initial mass activity of 0.558 A mg−1Pt (@0.9 V vs RHE), which is 3.30 times higher than commercial Pt/C and outperforms most of the reported Pt catalysts. Beyond that, the catalyst also exhibits significantly improved durability with 9 mV negative shift in half-wave potential after 20 K cycles, while commercial Pt/C benchmark displays a 52 mV negative shift. The structural characterizations after durability test confirmed that the pore-confinement design can effectively inhibit the particle agglomeration with negligible increase in particle size. This catalyst design can be easily applicable to other metal-based catalyst and heteroatoms doping.