Ni3S4/NiS/rGO as a promising electrocatalyst for methanol and ethanol electro-oxidation

Abstract

We present a one-step hydrothermal synthesis of hybrids consisting of nickel sulfides in the form of Ni3S4–NiS (NN) and Ni3S4–NiS-rGO (NNR), i.e. with the addition of reduced graphene oxide (rGO), for application as catalysts. After accurate physical characterization and confirmation of successful synthesis, we evaluate the ability of these catalysts in the processes of methanol and ethanol oxidation. The precise electrochemical analyses show relatively good potential and excellent cyclic stability in methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR) processes. The comparison of the two catalysts shows the superiority of NNR over NN, confirming that rGO introduces a higher specific surface area and a higher electrical conductivity in the NNR structure. In the process of MOR, NNR has an oxidation peak at a current density of 55 mA cm−2 and a peak potential of 0.54 V. In EOR, this peak is located at a current density of 11 mA cm−2 and at a peak potential of 0.59 V. NNR has 97% and 94% stability in MOR and EOR after 1000 consecutive cycles, respectively, which are acceptable values.