Simultaneous enhancements in stability and CO tolerance of Pt electrocatalyst by double poly(vinyl pyrrolidone) coatings

Abstract

CO poisoning and low durability of the anodic electrocatalyst is one of the obstacles restricting the practical application of direct methanol fuel cells (DMFCs). In this work, a highly CO-tolerant and durable platinum (Pt) electrocatalyst is fabricated by introducing double poly(vinyl pyrrolidone) (PVP) layers into the electrocatalyst, in which the first PVP layer is utilized to coat carbon black before Pt deposition and the second PVP layer is laid on the Pt nanoparticles. The first PVP layer on carbon black is favorable for higher Pt utilization efficiency attributed to the capping of micropores on carbon black. The second PVP layer on the Pt nanoparticles facilitates the removal of adsorbed CO species on the Pt nanoparticles and suppresses the Pt aggregation; meanwhile, the PVP layer on the Pt nanoparticles showed a negligible effect (7%) on the electrochemical surface area (ECSA) and methanol oxidation reaction (MOR). Thus, double PVP layers coated Pt electrocatalyst is potentially utilizable for real DMFC operation.