Utilization of the superior properties of highly mesoporous PVP modified NiCo2O4 with accessible 3D nanostructure and flower-like morphology towards electrochemical methanol oxidation reaction

Up to this date, researchers are still facing difficulties to expand the technology of direct methanol fuel cells (DMFCs) because of the high overpotential required to oxidize the methanol and its relatively poor performance due to CO poisoning of the leading-high cost anode catalyst. In line with this, we have successfully modified the morphological structure and composition of low cost cobalt based-metal oxides, MCo2O4 (M=Zn and Ni), with the simple and noble use of polyvinyl pyrrolidone (PVP) as growth modifier and surface stabilizer during the synthesis of nanoparticles in our previous reports, which shown high electrocatalytic activity and strong stability. Due to the good performance of our PVP modified MCo2O4 towards pseudocapacitor and oxygen evolution reaction applications, we decided to extend our research study to methanol oxidation reaction. Remarkably, PVP modified NiCo2O4 electrode directly grown on nickel foam substrate via a simple hydrothermal process exhibited better performance compared with PVP modified ZnCo2O4 and NiCo2O4 without PVP. It had obtained a remarkably low onset potential of 0.285V and high current density of 280mA cm(-2), and shown great stability and high poison tolerance during a continuous CV cycling and Chronoamperometry test, which attained high efficiency of 86.86% and 98.52%, respectively. These positive results of PVP modified NiCo2O4 electrode towards MOR might be attributed to its hierarchical 3D nanostructures with highly mesoporous surface and large surface area which may have provided numerous electroactive sites, and the exceptional corrosion stability of NiCo2O4 electrode in alkaline solution. (C) 2018 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.