AuCo3O4/C – Different Fabrication Methods and Application for Fuel Cell Reactions

Abstract

Nanoscale materials are very important in many industries. There are many various synthesis methods such as adsorption, electroless deposition, galvanic displacement or microwave irradiation methods which let to fabricate nanomaterials. Lately, microwave irradiation is used as a rapid convenient method which gives excellent yields and higher purity of the products than conventional methods. Nanoparticles-based catalysts are usually heterogeneous catalysts broken up into metal nanoparticles in order to speed up the catalytic process. Metal nanoparticles have a higher surface area so there is increased catalytic activity because more catalytic reactions can occur at the same time. Nanoparticles catalysts can also be easily separated and recycled with more retention of catalytic activity than their bulk counterparts. Nanoparticles of gold are attractive for their interaction with other compounds and property to attract catalytic active groups.In this work, we investigated the influence of synthesis method to the electrocatalytic activity of catalyst. Therefore, Au nanoparticles were deposited on the Co3O4/carbon (Co3O4/C) substrate using microwave irradiation AuCo3O4/C-1, AuCo3O4/C-2 and impregnation AuCo3O4/C-3 methods. The composition, morphology and structure of the prepared catalysts were characterized using Inductively Coupled Plasma Optical Emission Spectroscopy, Field Emission Scanning Electron Microscopy, Transmission Electron Microscopy, X-ray Photoelectron Spectroscopy and X-ray diffraction. The electrocatalytic properties of prepared catalysts were investigated towards ethylene glycol electro-oxidation and oxygen electro-reduction reactions in an alkaline medium. Electrochemical analysis was performed using a rotating disc electrode and the Autolab electrochemical workstation.It has been determined, that in all cases modification of Co3O4/C catalyst by gold improved the electrocatalytic properties of synthesized AuCo3O4/C catalysts. As-prepared AuCo3O4/C catalysts showed an enhanced electrocatalytic activity towards the electro-oxidation of ethylene glycol and electro-reduction of oxygen in an alkaline medium compared with that obtained for the Co3O4/C or Au/C catalysts. The AuCo3O4/C catalysts prepared by microwave irradiation heating demonstrated up to 3 times higher electrocatalytic activity towards the electro-oxidation of ethylene glycol and up to 2 fold higher electrocatalytic activity towards electro-reduction of oxygen compared with that of the AuCo3O4/C catalyst prepared using impregnation.