Facile preparation of a methanol catalyst with ultra-high voltage efficiency and super-durability: Pt pollution introduction by composite electrodeposition

Abstract

Noble metal catalysts are still the best methanol oxidation reaction (MOR) catalysts for direct methanol fuel cells nowadays, because the MOR onset potential of non-noble metal-based catalysts is much higher than that of Pt (usually greater than 1.35 V vs. RHE), so that the potential of the MOR is even higher than that of the oxygen reduction reaction and cannot form a cell. Here, we develop a high-performance non-noble-metal based (CoSn) MOR catalyst with a small amount (3.2 wt%) of Pt, which exhibits overpotential even lower than that of Pt/C (260 mV lower), unparalleled stability (retains 610 mA mg_Pt⁻¹ after chronoamperometry testing for 28 h, the best value for methanol oxidation reported to date) and high methanol oxidation activity (3680 mA mg_Pt⁻¹). We synthesize this CoSn–Pt catalyst by innovatively utilizing a Pt plate as a counter electrode (which is always avoided to prevent potential pollution of Pt in the past) to realize composite electrodeposition in a deep eutectic solvent.