The influence of annealing temperature on the electrocatalytic performance of NiCo2O4/rGONRs in the methanol oxidation reaction

Nickel oxide and cobalt oxide have been widely used as adsorbents, gas sensors, catalysts, and electrode materials. In this work, nickel cobaltite nanoparticles were anchored on graphene oxide nanoribbons (NiCo2O4/rGONRs) via a hydrothermal process. The influence of annealing temperature on the crystalline structure and the electrocatalytic performance of nanocomposites was investigated. The electrocatalytic activity of nanocomposites in the methanol oxidation reaction was obtained in the following order: NiCo2O4/rGONR(400)> NiCo2O4/rGONR(600)> NiCo2O4/rGONR(200)> NiCo2O4(400)> NiCo2O4/rGONR(0). The results approved that the increase of annealing temperature up to 400 °C promotes the catalytic performance and subsequently, enhances the methanol oxidation kinetics through changing crystalline structure. The comparison of NiCo2O4(400) nanoparticles with NiCo2O4/rGONR(400) nanocomposite showed that the presence of rGONRs as substrate improves the electrochemical activity and stability of NiCo2O4 nanoparticles. Based on this, NiCo2O4/rGONR(400) nanocomposite has good potential for use as a catalyst in the electrooxidation process of methanol due to its lower onset potential, and charge transfer resistance and greater electrochemical surface area.