Enhanced electrocatalytic properties of Pt–chitosan nanocomposite for direct methanol fuel cell by LaFeO3 and carbon nanotube

Abstract

Incorporation of LaFeO3 nanoparticles (LaFeO3NPs) and carbon nanotubes (CNT) into Pt–chitosan for methanol electrooxidation has been studied. LaFeO3 nanoparticles are successfully prepared by a rapid microwave-assisted co-precipitation method. The formation of LaFeO3NPs is confirmed by X-ray powder diffraction (XRD), Fourier transformed infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray (EDX) techniques. Modified glassy carbon (GC) with Pt nanoparticles (PtNPs), LaFeO3NPs and chitosan (CH) as binder (GC/PtNPs–LaFeO3NPs–CH) and GC/PtNps–LaFeO3NPs–CNT–CH electrodes are prepared by layer by layer technique and their catalytic activity toward methanol oxidation is investigated. It is demonstrated that the catalytic activity of PtNPs can be significantly enhanced by mixing with LaFeO3NPs and CNT. The Pt–LaFeO3NPs–CNT catalyst has a better durability compared to the Pt–LaFeO3NPs catalyst due to the existence of CNT, which prevents dissolution of PtNPs. Moreover, PtNPs–LaFeO3NPs–CH shows improved methanol oxidation activity, but its direct methanol fuel cells (DMFC) performance is found to be inferior to that measured for PtNps–LaFeO3NPs–CNT–CH. The factor influencing PtNPs utilization in the methanol oxidation reaction is intrinsically related to PtNPs formation but using LaFeO3NPs helps in enhancing the DMFC performance with low Pt loading.