Pt/graphene with intercalated carbon nanotube spacers introduced by electrostatic self-assembly for fuel cells

Abstract

Abstract Although graphene exhibits an appealing array of properties that are ideally suited to their use as catalyst supports for fuel cells, they suffer from a serious issue of graphitic restacking due to van-der-Waals force and π-π interaction, making much of the catalyst surface inaccessible to reaction. In this work, highly active and stable platinum nanoparticles supported on graphene with intercalated carbon nanotubes (CNTs) are prepared by electrostatic self-assembly for fuel cell applications. CNTs, which functioned as spacers, are wedged between graphene sheets via electrostatic self-assembly resulting in interconnected 3-D sandwiched structure. The intercalated CNTs inhibit restacking and lead to increased Pt utilization efficiency through improved mass transport. An enhancement factor of 114% for Pt utilization efficiency and electrochemical surface area (ESA) is found for the optimized Pt/rGO-CNT relative to that of Pt/rGO. Compared with the state-of-the-art Pt/C, the hybrid catalyst show markedly enhanced stability, i.e., with an ESA retention of 62% after cycling the catalyst in 0.5 M H2SO4 from −0.2–1.0 V up to 2000 scans, whereas the ESA retention for commercial Pt/C is only 19%. These results indicate our unique approach is promising to employ graphene as Pt catalyst support aiming for high activity and stability.