Abstract

Electrocatalytic systems utilizing carbon (Vulcan)-supported PtRh nanoparticles (PtRh/Vulcan) admixed with either molybdenum oxide or tungsten oxide were tested and compared during electrooxidation of ethanol. The systems' performance was diagnosed using electrochemical techniques such as voltammetry and chronoamperometry. The proposed electrocatalytic materials were also characterized with X-ray diffraction (XRD), transmission and scanning electron microscopies (TEM and SEM), as well as SEM-coupled energy dispersive X-ray spectroscopy (SEM-EDX). For both systems containing molybdenum and tungsten oxides, enhancements in catalytic activities (relative to the behavior observed at bare PtRh/Vulcan nanoparticles) were found during ethanol electrooxidation at room temperature (22 °C). Further, it was from chronoamperometric current (density)–time responses that anodic electrocatalytic currents measured at 0.3 V (vs. RHE) were more than 20% higher in the case of the MoO3-containing PtRh/Vulcan system relative to that utilizing WO3. The diagnostic “CO-stripping” experiments were consistent with the view that addition of molybdenum oxide or tungsten oxide to PtRh/Vulcan tended to shift potential for the oxidation of inhibiting CO-adsorbate ca. 80 or 40 mV towards less negative values in comparison to the analogous but oxide-free system. The fact that carbon (Vulcan)-supported PtRu nanoparticles exhibited higher electrocatalytic reactivity observed phenomena may be attributed to specific interactions between noble metal centers and the oxides in addition to chemical reactivity of metal oxo groups in the vicinity of PtRh/Vulcan at the electrocatalytic interface.

Highlights

  • Fuel cell technology has become increasingly significant during recent years because of growing industrialization and related energy consumption, problems with environmental protection as well as limited resources of fossil fuels

  • To get some insight into the structure and morphology of the PtRh/Vulcan nanoparticles modified with molybdenum and tungsten oxides, the samples were examined by X-ray diffraction (XRD) (Fig. 1)

  • We have demonstrated an improvement in carbon-supported PtRh nanoparticles for the electrocatalytic oxidation of ethanol by adsorption of metal oxides (MoO3 or WO3) thereon

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Summary

Introduction

Fuel cell technology has become increasingly significant during recent years because of growing industrialization and related energy consumption, problems with environmental protection as well as limited resources of fossil fuels. The electrocatalytic activity of carbonsupported PtRh nanoparticles (PtRh/C), that have been intentionally modified or admixed with metal oxide species such as MoO3 or WO3, is investigated for the electrooxidation of ethanol. To get some insight into the structure and morphology of the PtRh/Vulcan nanoparticles modified with molybdenum and tungsten oxides, the samples were examined by XRD (Fig. 1).

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