In situ growth of Ni/Ni3S2–MoO2 nanocrystals on carbon cloth for the enhanced electrocatalytic oxidation of methanol

Abstract

The rational design and construction of high-performance Ni-based methanol oxidation catalyst is the key technology for direct methanol fuel cell (DMFC). In this work, Ni/Ni3S2–MoO2@CC composite is constructed by in-situ growth of Ni/Ni3S2–MoO2 nanoparticles on carbon cloth (CC) by a two-step method, which has excellent activity and stability for methanol oxidation reaction (MOR), that is, the current density (j) can reach 240.08 mA cm−2 at the potential of 1.67 V. The potentials at different j are 10 mA cm−2@1.37 V and 100 mA cm−2@1.50 V, respectively. Meanwhile, the retention rate of j is 90.36 % after 12 h CA stability test. Based on density functional theory (DFT) calculation, the excellent properties of Ni/Ni3S2–MoO2@CC composite are mainly attributed to its higher conductivity and higher carrier density accelerate the charge transfer in the MOR process, its Ni and Mo sites facilitate the adsorption of methanol as a reactant and desorption of carbon dioxide as a product, thus promoting the kinetics of MOR. In addition, the reaction mechanism of MOR on the Ni/Ni3S2–MoO2@CC is more likely to follow the formation path of CO* intermediates. This work provides a feasible route for the synthesis of high performance electrocatalysts for the MOR.