Preparation of a Pt/NiFe layered double hydroxide/reduced graphene oxide composite as an electrocatalyst for methanol oxidation

Abstract

Reduced graphene oxide (RGO) has been shown to be an excellent support for Pt-based nanoparticles due to its large surface area and abundant chemical functional groups/defects available for anchoring. However, the restacking that occurs during the reduction of graphene oxide precludes its independent application. A variety of methods have been utilized to solve this problem, including surface modification, element doping, and insertion of separator. A novel NiFe layered double hydroxide/reduced graphene oxide (NiFe-LDH/RGO) composite was prepared by a facile one-pot solvothermal process using LDH as an effective separator, with subsequent Pt nanoparticles deposition via electrodeposition. The activity of this Pt/NiFe-LDH/RGO catalyst towards the methanol oxidation reaction (MOR) in alkaline media was studied by cyclic voltammetry (CV), and its stability was investigated by chronoamperometry (CA). The morphology was characterized by transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and scanning electron microscopy (SEM). The structure was determined by examining X-ray diffraction (XRD) patterns. The resulting Pt/Ni-Fe LDH/RGO electrocatalyst exhibits higher peak current density (949.3 mA mg−1), larger electrochemically active surface area (24.6 m2 g−1Pt) and better stability for methanol oxidation than its RGO-free counterpart (512.3 mA mg−1, 17.7 m2 g−1Pt). Moreover, the Pt nanoparticles mean diameter of Pt/NiFe-LDH/RGO electrocatalyst is 6.27 nm, which is much smaller than other contrast.