Pt nanoparticles deposited on dihydroxy-polybenzimidazole wrapped carbon nanotubes shows a remarkable durability in methanol electro-oxidation

Abstract

The fabrication of a highly CO-tolerant and durable anodic electrocatalyst is extremely important for the widespread application and commercialization of the direct methanol fuel cells (DMFCs). Here, we deposited the platinum nanoparticles (ca. ∼4 nm) on the multi-walled carbon nanotubes (MWNTs) after wrapping by the dihydroxy-polybenzimidazole (2OH-PBI). The Pt utilization efficiency of the as-synthesized electrocatalyst reached ∼70%. Meanwhile, the CO-tolerance was ∼1.5 times higher than that of the commercial CB/Pt due to the OH groups on the 2OH-PBI, facilitating the formation of PtOH as well as the consumption of PtCO. The electrochemical surface area (ECSA) and mass activity measured in the methanol oxidation reaction (MOR) decreased by ∼10% and 50% after 100,000 potential cycles from 1.0 to 1.5 V vs. RHE, respectively, while, the commercial CB/Pt lost ∼46% and 50% after 10,000 potential cycles, indicating that the as-synthesized electrocatalyst showed 10 times higher durability compared to the commercial CB/Pt. Such durable electrocatalyst with high CO-tolerance is applicable in the DMFC.