Pt supported on Nanostructured NCNTs/RGO Composite Electrodes for Methanol Electrooxidation (original) (raw)
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International Journal of …, 2011
Nanostructured PtRu and Pt dispersed functionalized grapheneefunctionalized multi walled carbon nanotubes (PtRu/(f-Gef-MWNT)), (Pt/(f-Gef-MWNT)) nanocomposites have been prepared. Electrochemical studies have been performed for the methanol oxidation using cyclic voltammetry (CV) and chronoamperometry technique. Full cell measurements have been performed using PtRu nanoparticles dispersed on the mixture of functionalized graphene (f-G) and functionalized multi walled carbon nanotubes (f-MWNT) in different ratios as anode electrocatalyst for methanol oxidation and Pt/f-MWNT as cathode catalyst for oxygen reduction reaction in direct methanol fuel cell (DMFC). In addition, full cell measurements have been performed with PtRu/(50 wt% f-MWNT þ 50 wt% f-G) and Pt/(50 wt% f-MWNT þ 50 wt% f-G) as anode and cathode electrocatalyst respectively. With PtRu/(50 wt% f-MWNT þ 50 wt% f-G) as anode electrocatalyst, a high power density of about 40 mW/cm 2 has been obtained, in accordance with cyclic voltammetry studies. Further enhancement in the power density of about 68 mW/cm 2 has been observed with PtRu/(50 wt% f-MWNT þ 50 wt% f-G) and Pt/(50 wt% f-MWNT þ 50 wt% f-G) as electrocatalyst at anode and cathode respectively. These results have been discussed based on the change in the morphology of the f-G sheets due to the addition of f-MWNT.
Synthesis of PtRu/C-CNTs electrocatalysts for DMFCs with treated-CNTs and composition regulation
Advances in Natural Sciences: Nanoscience and Nanotechnology, 2014
In the present work, PtRu/C-CNTs catalyst samples were studied for potential applications in direct methanol fuel cells (DMFCs). Carbon nanotubes (CNTs) were treated by H 2 SO 4 98% and HNO 3 65% at different temperatures and with different stirring periods. As a result, the PtRu/C-CNTs catalyst was successfully synthesized by using H 2 PtCl 6 and RuCl 3 precursors with the efficient reduction of NaBH 4 agent in ethylene glycol (e.g.). In addition, we controlled the ratios of treated-CNTs on carbon vulcan XC-72 treated-CNTs substrate (C-CNTs) with the different values: 50 wt%, 25 wt%, and 12.5 wt%, respectively. The PtRu/C-CNTs electrocatalyst samples were investigated by experimental methods including x-ray diffraction (XRD), transmission electron microscopy (TEM), and cyclic voltammetry (CV). Importantly, the CV results show the best treated-CNTs and the most suitable ratio of CNTs composition on C-CNTs substrate to be controlled in order to produce various efficient PtRu/C-CNTs catalysts with high catalytic activity for DMFCs.
Pt-based catalysts are promising anodic catalysts for direct methanol fuel cells (DMFCs). However, the slow reaction kinetics, CO poisoning and high cost of Pt, reduce the performance of DMFCs. In this study, polyol synthesis as one-step simple and economic method was applied to prepare graphene supported Pt-Ni catalysts (G/Pt-Ni). The reduction of graphene oxide to graphene and the deposition of well-dispersed Pt-Ni alloy nanoparticles on graphene were achieved simultaneously in ethylene glycol which acts as reducing agent and solvent as well. Four catalysts containing different Ni content were synthesized, i.e. G/Pt, G/Pt1-Ni1, G/Pt2-Ni1 and G/Pt3-Ni1. The total metals loading in all batches were 30 wt.-%. The prepared catalysts were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and energy-dispersive X-ray spectroscopy (EDX). The electrocatalytic activities towards methanol oxidation reaction (MOR) have been investigated using cyclic voltammetry (CV) and chronoamperometry (CA) in 0.5 M H2SO4 containing 1 M CH3OH. The G/Pt-Ni showed superior mass and specific activities, good poison tolerance and enhanced stability toward MOR compared to that of G/Pt. The G/Pt1-Ni1 catalyst showed the highest electrocatalytic activity and stability toward MOR, better tolerance to the intermediate species, and favors long-term application as an anode material for DMFCs.
Journal of Applied Electrochemistry, 2009
This work tries to study the problem of methanol crossover through the polymer electrolyte in direct methanol fuel cells (DMFCs) by developing new cathode electrocatalysts. For this purpose, a series of gas diffusion electrodes (GDEs) were prepared by using single-walled carbon nanotubes (SWCNTs) supported Pt-Pd (Pt-Pd/ SWCNT) with different Pd contents at the fixed metal loading of 50 wt%, as bimetallic electrocatalysts, in the catalyst layer. Pt-Pd/SWCNT was prepared by depositing the Pt and Pd nanoparticles on a SWCNTs support. The elemental compositions of bimetallic catalysts were characterized by inductively coupled plasma atomic emission spectroscopy (ICP-AES) system. The performances of the GDEs in the methanol oxidation reaction (MOR) and in the oxygen reduction reaction with/without the effect of methanol oxidation reaction were investigated by means of electrochemical techniques: cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS). The results indicated that GDEs with Pt-Pd/SWCNT possess excellent electrocatalytic properties for oxygen reduction reaction in the presence of methanol, which can originate from the presence of Pd atoms and from the composition effect.
Electrochimica Acta, 2013
Different carbon materials with high electrical conductivity have been studied as electrocatalyst support for direct alcohol fuel cells (DAFCs). The aim of the work was to establish the influence of the support on the catalyst properties and to improve their efficiency in the fuel cell. Carbon nanofibers (CNFs), carbon nanocoils (CNCs) and ordered mesoporous carbons (gCMK-3) have been used for synthesizing platinum catalysts by the polyol method. Results have been compared with those obtained for a platinum catalyst supported on Vulcan XC-72R, prepared by the same method, and for the commercial Pt/C catalyst from E-TEK. It has been demonstrated that novel carbon supports could help to oxidize CO adsorbed on platinum particles more easily than the commercial carbon support and improve the alcohol oxidation reaction, both in terms of onset potential and current density. The catalyst supported on gCMK-3 carbon resulted to be the most effective in both the methanol and ethanol oxidation, which can be attributed to its ordered structure and high electrical conductivity.