High stability and performance of PtRu electrocatalyst derived from double polymer coatings

Abstract

In this work, we focus on the durability, CO tolerance and sluggish methanol oxidation reaction (MOR) of PtRu electrocatalyst. Here, we fabricate a new PtRu electrocatalyst supported on carbon black (CB), in which the PtRu nanoparticles are structurally sandwiched by poly(vinyl pyrrolidone) (PVP) and poly(2,5-benzimidazole) (ABPBI). Due to the first coating (PVP) on CB, the micropores on CB are capped resulting in high Pt utilization efficiency (94%) and catalytic activity toward methanol oxidation. Meanwhile, the second coating (ABPBI) on PtRu nanoparticles fabricated via in-situ polymerization improves the PtRu stability and decelerates the Ru dissolution leading to stable electrochemical surface area (ECSA), MOR activity and CO tolerance during the durability test. Without ABPBI coating, ECSA and catalytic activity remain only 50% after potential cycling. Additionally, the fuel cell performance of double polymer coated electrocatalyst reaches 103 mW cm−2, which is among the highest values reported in the recent literatures.