Bottom-up design of a stable CO-tolerant platinum electrocatalyst with enhanced fuel cell performance in direct methanol fuel cells

Abstract

Sluggish methanol oxidation reaction (MOR) and CO poisoning of platinum electrocatalysts are critical problems in direct methanol fuel cells (DMFCs). Here, we design a stable CO tolerant platinum electrocatalyst via a bottom-up method, in which the platinum nanoparticles are deposited on carbon black after coating with polybenzimidazole (PBI) and poly(vinyl pyrrolidone) (PVP). By comparison with the PVP post-coated electrocatalyst (CB/PBI/Pt/PVP), the PVP pre-coated electrocatalyst (CB/PBI/PVP/Pt) exhibits comparable durability and CO tolerance due to the similar amount of PVP in the electrocatalyst, suggesting the PVP pre-coating method shows negligible effect on CO tolerance and durability, while the Pt utilization efficiency, methanol oxidation activity and power density of CB/PBI/PVP/Pt are 1.6 times higher than those of CB/PBI/Pt/PVP. Thus, the PVP pre-coated electrocatalyst has better activity due to the non-coated Pt nanoparticles. Meanwhile, CB/PBI/PVP/Pt exhibits highly stable CO tolerance during the durability test, while the CO tolerance of the commercial CB/PtRu seriously deteriorates during the durability test due to the dissolution of Ru nanoparticles. To the best of our knowledge, the maximum power density of CB/PBI/PVP/Pt (104 mW cm⁻²) is one of the highest values in recent publications.