Pt particles supported on conducting polymeric nanocones as electro-catalysts for methanol oxidation (original) (raw)
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DergiPark (Istanbul University), 2021
Facile synthesis of Pt@PTH catalyst on pencil graphite electrode for electrooxidation of methanol was described. Influence of experimental conditions on the performance of the catalyst system was studied by recording cyclic voltammograms of methanol solution containing H2SO4 as the supporting electrolyte. The catalyst prepared under optimum conditions was physically characterized using Scanning Electron Microscopy, Energy Dispersive X-Ray Dispersion and Elemental Mapping methods. Electrochemical characterization was performed by cyclic voltammetry in H2SO4 solution.
Solvation of energy crises is the need of the era which urges for alternate energy resources. Direct methanol fuel cells (DMFCs) are an integral part of alternate energy and fuel concerns. This study demonstrates the facile fabrication of polydiphenylamine/phosphotungstic acid/platinum (PDPA/PTA/Pt) nanocomposites modified electrode via electrodeposition method for efficient electro-oxidation of methanol in acidic medium. The physicochemical characterization of PDPA/PTA/Pt nanocomposite modified electrode morphology using SEM with EDX mapping, and crystallinity behavior was examined using powder XRD analysis. The morphology of the PDPA/PTA/Pt nanocomposites demonstrates that the size of Pt nanospheres is ~200 nm, and the size of PTA nanorods is ~300 nm in the PDPA matrix. The electrochemical properties were also evaluated using cyclic voltammetry, chronoamperometric and electrochemical impedance studies techniques. The PDPA/PTA/Pt nanocomposite modified electrode showed superior electrocatalytic activity, higher current density (14.807 mA cm − 2), longer stability and durability (30 min), and excellent catalytic poisoning tolerance to carbonaceous species accumulation towards methanol electro-oxidation reaction (MEOR), which is because of the synergistic existence of Pt nanospheres and PTA nanorods with PDPA matrix which enhances the electron transfer. The obtained results proved that the developed electro-catalyst is an excellent alternative for efficient MEOR in fuel cells applications.
Bulletin of Materials Science, 2018
A novel polymer-carbon (PTh-C) nanocomposites containing different percentages of polythiophene (10, 20 and 50% (w/w)) and carbon (Vulcan XC-72) was prepared by a facile solution dispersion method and used to support platinum nanoparticles. The effect of using different percentages of polythiophene in nanocomposites and subsequently prepared electrocatalysts was investigated. The resultant electrocatalysts were extensively characterized by physical (X-ray diffraction (XRD) and transmission electron microscopy (TEM)) and electrochemical (cyclic voltammetry (CV)) techniques. The TEM results showed that the fine Pt nanoparticles prepared by ethylene glycol (EG) method were distributed on the surface of the 50% PTh-C nanocomposites successfully. From the XRD patterns, the average size of dispersed Pt nanoparticles with the face-centered cubic (fcc) structure on 50% PTh-C, 20% PTh-C, 10% PTh-C and carbon were about 4.9, 5.2, 5.4 and 6.1 nm, respectively. The conductivity of PTh-C with different percentages of pure PTh was compared with the conductivity of the corresponding support of pure PTh. It is observed that the conductivity of 50% PTh-C nanocomposites is about 600 times higher than that of pure PTh. Finally, CV measurements of hydrogen and methanol oxidations indicated that Pt/50% PTh-C had a higher electrochemical surface area and higher catalytic activity for methanol oxidation reaction compared to other electrocatalysts. These measurements showed that the Pt/50% PTh-C electrocatalyst by the value of 3.85 had higher I f /I b ratio with respect to Pt/10% PTh-C and Pt/20% PTh-C by the values of 2.66 and 2.0, respectively.
Research on Chemical Intermediates
Poly (o-phenylenediamine) (PoPD) microrods were obtained by interfacial polymerization using ferric chloride as oxidant and without any template or functional dopant. Pt/PoPD nanocatalysts were prepared by the reduction of chloroplatinic acid with sodium borohydride, and the composite catalysts formed were characterized by X-ray diffraction and electrochemical methods. The nanocomposite of Pt/PoPD microrods has been explored for their electro-catalytic performance towards oxidation of methanol. The electro-catalytic activity of Pt/PoPD was found to be much higher (current density 1.96 mA/cm2 at 0.70 V) in comparison to Pt/Vulcan electrodes (the current density values of 1.56 mA/cm2 at 0.71 V) which may be attributed to the microrod morphology of PoPD that facilitate the effective dispersion of Pt particles and easier access of methanol towards the catalytic sites.
Preparation and characterization of Pt nanowire by electrospinning method for methanol oxidation
Electrochimica Acta, 2010
Pt nanowires are prepared by treating electrospun polyvinyl pyrrolidone (PVP)-Pt composite fibers at high temperatures in an air atmosphere and their activities toward a methanol oxidation reaction (MOR) are investigated. Thermogravimetric analysis (TGA) and inductively coupled plasma-atomic emission spectroscopy (ICP-AES) results indicate that the electrospun PVP-Pt composite fibers thermally decompose at 250 • C, which leads to the removal of 98 wt% of the PVP polymer and the simultaneous reduction of the Pt precursor to a Pt nanowire. The physical and electrochemical properties of Pt nanowires are found to be affected by the heat treatment conditions such as heating rate, time, temperature, and atmosphere. Furthermore, polymer fibers subjected to a pyrolization process in nitrogen followed by exposure to an air atmosphere enhance the surface area of the Pt nanowires, leading to high electrochemical activity toward a MOR. The detailed physical and electrochemical properties of the Pt nanowires are characterized by various spectroscopic and electrochemical techniques, and the possibilities of using them as electrocatalysts in a fuel cell are explored.
Energy, 2015
In this paper, a facile electrochemical approach is reported towards the fabrication of Pt needle-like NFs (nanoflowers) at the surface of GCE (glassy carbon electrode). The morphology and composition of the Pt NFs are characterized by SEM (scanning electron microscopy) and EDS (energy dispersive spectroscopy), respectively. Taking methanol oxidation as a model reaction in an acid medium, the electrocatalytic performance of as-prepared Pt NFs has been evaluated by CV (cyclic voltammetry), chronoamperometry and EIS (electrochemical impedance spectroscopy) techniques. These 3D (three dimensional) NFs exhibit the excellent electrocatalytic activity and high level of poisoning tolerance to the carbonaceous oxidative intermediates for the electro-oxidation reaction in acidic media. In addition, EIS information discloses different impedance behaviors for methanol electrooxidation at various potentials on the Pt NFs catalyst and also the change of rate-determining step with increasing potential. The comparison of Pt NFs and Pt NPs (nanoparticles), prepared by electrodeposition in the presence of hydrogen bubbles, shows that the NFs catalyst has higher activity, better long-term stability and lowers Pt loading. The simplicity of method and quality of prepared surfaces suggest applications in catalysis where a convenient method to prepare Pt catalysts with high surface area in one step is desirable.
Elsevier, 2018
Available online xxx Keywords: Liquid-liquid interface Thin film Supported catalyst Methanol oxidation a b s t r a c t Nano alloys contain noble metal nanostructures exhibit a wide theoretical and experimental interest in the field of fuel cells. Hard endeavors have been enhanced to improve the catalytic performance and minimize the usage of precious metals by alloying them with non-precious ones. Formation of bimetallic and trimetallic noble metal alloys with well-designed structures provide the opportunity to reach this goal. In this study, we first discuss the synthesis of noble metal alloy nanostructured thin films such as PtCu, PdCu, PtCu/reduced-graphene oxide (RGO), PdCu/RGO, PtCo, PtCo/RGO, PtPdCu and PtPdCu/RGO via a simple reduction of organometallic precursors including [PtCl 2 (cod)] and [PdCl 2 (cod)], (cod ¼ cis, cis-1,5-cyclooctadiene), in the presence of [Cu(acac) 2 ] and [Co(acac) 3 ] (acac ¼ acetylacetonate) at oil/water interface and room temperature, including nano-particles and nanosheets. Then the effects of the well-defined nanostructures on the improved electrochemical properties are outlined. Finally, we conclude that these non-precious bi and trimetallic alloy nanostructured thin films have better electrocatalytic performance than Pt monometallic thin films and other Pt nanostructures due to the geometric, electronic and stabilizer effect.