Bimetallic NiCo metal-organic frameworks for efficient non-Pt methanol electrocatalytic oxidation

Abstract Bimetallic NiCo-MOF was synthesized via the one-pot synthesis method by using 2,2′-bipyridine-5,5′-dicarboxylic acid as the building block with nickel acetate and cobalt acetate as the mixed precursors. Co and Ni ions were concurrently coordinated with carboxyl groups and pyridyl nitrogen donors. Basic characterizations of the series of MOFs were investigated by diverse techniques. The developed NiCo-MOF consisted of mixed-valence Co(II)/Co(III) and Ni(II)/Ni(III) and rich functional groups. The MOF exhibited a large specific surface area, evenly distributed nanocubes, and high electrocatalytic activity. Compared with the Ni-MOF, Co-MOF, and commercial Pt/C(20 %), the NiCo-MOF catalyst had improved electrocatalytic activity toward methanol oxidation reaction (MOR). High current density of 225 mA cm−2 at the potential of 1.6 V versus RHE in alkaline medium was achieved. Moreover, remarkable cycling stability in the MOR conditions was observed and only showed a slight decline after 5000 s. The catalytic mechanism of NiCo-MOF toward MOR was provided.