Modification of Carbon Black with Hydrogen Peroxide for High Performance Anode Catalyst of Direct Methanol Fuel Cells (original) (raw)
Related papers
C, 2021
A series of PtRu/carbon black catalysts were prepared by means of deposition-precipitation and reduced by various reducing agents. NaBH4, HCHO and NaH2PO2, respectively, were used as the reduction agents. Some of the samples were reduced by various amounts of NaH2PO2 to investigate the effects of P/Pt ratios on the characteristics and activity of the catalyst. These catalysts were characterized by X-ray diffraction and transmission electron microscopy. The components of these catalysts were detected by X-ray fluorescence, X-ray photoelectron microscopy, and extended X-ray absorption of fine structures (EXAFS). The methanol oxidation ability of the catalysts was tested by cyclic voltammetry measurement. The results show that NaH2PO2 could effectively reduce the particle size of PtRu metal. It can suppress the growth of metal particles. In addition, the P/Pt ratio is crucial. The catalyst reduced by NaH2PO2 with a P/Pt ratio of 1.2 had the highest activity among all catalysts. It had ...
Enhanced methanol electro-oxidation activity of PtRu catalysts supported on heteroatom-doped carbon
Electrochimica Acta, 2008
PtRu nanoparticles deposited on a carbon black substrate are catalysts commonly employed for the electrooxidation of methanol and carbon monoxide-containing hydrogen feeds [1,. However, improvement of effective electrocatalysts is an essential goal in the development of a practical DMFC. The use of carbon black as a support for noble metals is frequent in the electrodes of polymer membrane electrolyte fuel cells, but the impact of the chemical and physical properties of the carbon on electrocatalytic performance are not yet sufficiently understood. The presence of oxygen surface groups influences the surface behaviour of carbons to a considerable extent . As examples, the wettability and adsorptive behaviour of a carbon, as well as its catalytic and electrical properties, are influenced by the nature and extent of such surface groups. The varying role of oxygenated functionalities on the formation of the dispersed platinum has been established [5-8], but not with an additional metal such as ruthenium. In the present investigation we report how the performance in methanol electrooxidation of PtRu nanoparticles deposited on a carbon black substrate, previously functionalized with oxygen surface groups, is improved.
Carbon, 2005
PtRu nanoparticles deposited on a carbon black substrate are catalysts commonly employed for the electrooxidation of methanol and carbon monoxide-containing hydrogen feeds [1,. However, improvement of effective electrocatalysts is an essential goal in the development of a practical DMFC. The use of carbon black as a support for noble metals is frequent in the electrodes of polymer membrane electrolyte fuel cells, but the impact of the chemical and physical properties of the carbon on electrocatalytic performance are not yet sufficiently understood. The presence of oxygen surface groups influences the surface behaviour of carbons to a considerable extent . As examples, the wettability and adsorptive behaviour of a carbon, as well as its catalytic and electrical properties, are influenced by the nature and extent of such surface groups. The varying role of oxygenated functionalities on the formation of the dispersed platinum has been established [5-8], but not with an additional metal such as ruthenium. In the present investigation we report how the performance in methanol electrooxidation of PtRu nanoparticles deposited on a carbon black substrate, previously functionalized with oxygen surface groups, is improved.
Methanol electrooxidation on PtRu nanoparticles supported on functionalised carbon black
Catalysis Today, 2006
The effect of the preparation method of PtRu electrocatalysts and the chemical treatment of support on the performance for methanol electrooxidation has been studied. Carbon supported PtRu catalysts were synthesized from aqueous solution of H2PtCl6 and RuCl3 precursors by two different methods: colloidal (using NaHSO3) and impregnation. The carbon black Vulcan XC-72R was functionalised with H2O2 and HNO3. A commercial PtRu/C catalyst purchased from Johnson and Matthey was used as reference. The obtained electrocatalysts were characterized by XPS, XRD, TEM, EGA-MS, TGA and TXRF. Chronoamperometry in methanol and COads stripping experiments were conducted to check their electrocatalytic activity. Electrocatalysts obtained by the colloidal method and supported on functionalised carbon black with HNO3 and especially with H2O2, showed better performances (CO tolerance and superior methanol oxidation ability) than those obtained by the impregnation method and the commercial one.
Pt–NiO/C anode electrocatalysts for direct methanol fuel cells
Pt catalyst was supported on Vulcan XC-72R containing 5 wt.% NiO using NaBH4 as a reducing agent. The prepared catalyst was heat-treated at 400 ◦C. XRD, TEM and EDX analyses were applied to characterize Pt–NiO/C electrocatalyst. The introduction of NiO reduces the particle size of Pt crystallites. The electrocatalytic activity of Pt–NiO/C electrocatalysts was examined towards methanol oxidation reaction in 0.5 M H2SO4 solution using cyclic voltammetry and chronoamperometry techniques. A three fold increment in the oxidation current density was gained at Pt–NiO/C electrocatalyst compared to Pt/C one. The corresponding chronoamperograms showed high steady state current density values suggesting better stability of Pt–NiO/C electrocatalyst towards the carbonaceous poisoning species. The enhanced electrocatalytic performance and the long-term cycle durability of Pt–NiO/C electrocatalyst are attributed to the strong interaction between Pt and NiO and the formation of small Pt crystals.
The Journal of Physical Chemistry C, 2009
Ordered mesoporous thin-film carbon (TFC) material, of short channels vertical to the film, was synthesized by hard templating and deposited with PtRu nanocatalyst as an anodic material in a direct methanol fuel cell (DMFC). A series of PtRu bimetallic nanoparticles supported on ozone-pretreated carbon were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and extended X-ray absorption fine structure (EXAFS) analysis. For 20 wt % PtRu catalyst supported on a 30 min ozone-pretreated TFC gave an unprecedented current density of 410 mA/mg PtRu at 0.5 V relative to reference hydrogen electrode (RHE) at 60°C. The ozone treatment method introduces an easily controllable way for surface modification of mesoporous carbon which was found to modulate the surface composition and structure of the deposited PtRu nanoparticles. The greatly enhanced methanol electrochemical oxidation activity, at an optimum ozone treatment, was ascribed to facile transport in the TFC structure, high dispersion of bimetallic nanoparticles, and an optimized surface Pt and Ru ensembles of 70:30 ratios for a bifunctional efficiency.
Journal of Power Sources, 2008
An electrochemical method for the Pt nanoparticles deposition on porous and high surface carbon substrates (carbon black and carbon nanotubes), as an alternative way to prepare gas diffusion electrodes for polymer electrolyte fuel cells (PEFCs), is herein described. Pt nanoparticles well distributed and localized on the electrode surface were obtained by using an electric field. The electro-catalysts were prepared by single and multiple pulse galvanostatic polarizations in 1 M sulphuric acid + 5 mM exachloroplatinic acid solution. Chemical analysis, cyclic voltammetry and field emission gun scanning electron microscopy were used to determine the electrochemical features of Pt deposits and the influence of electro-deposition method on their nano-morphology. Electro-catalytic performances were studied by investigating the methanol oxidation reaction and the results are presented in form of surface specific activity and mass specific activity to take into account the electrochemical real surface and Pt loading. A comparison with commercial E-TEK Pt/C catalysts, prepared by traditional chemical reduction and heat treatment in hydrogen, shows that the electrodeposited catalyst presents higher activity at lower Pt loading.
Electrochimica Acta, 2012
Nitrogen-doped metal free carbon catalysts were prepared via pyrolysis of polyaniline-coated carbon in different ratios with varying nitrogen content. The surface states and surface composition were investigated using XPS (X-ray photoelectron spectroscopy). XPS analysis confirms the presence of pyridinic and pyrollic nitrogen in the carbon network that is responsible for the oxygen reduction activity. The shift in onset potential of oxygen reduction on C:N (1:1) is ∼0.3 V more positive compared to Vulcan carbon, shows improved activity toward oxygen reduction reaction in acidic electrolyte. Hydrodynamic voltammetric studies confirm that the reduction of oxygen follows the 4e − pathway which leads to the formation of water.
International Journal of Hydrogen Energy, 2010
Direct methanol fuel cell Cathode catalyst layer Pt black Carbon black additive a b s t r a c t Vulcan XC-72R, Ketjen Black EC 300J and Black Pearls 2000 carbon blacks were used as the additive in Pt black cathode catalyst layer to investigate the effect on direct methanol fuel cell (DMFC) performance. The carbon blacks, Pt black catalyst and catalyst inks were characterized by N 2 adsorption and scanning transmission electron microscopy (STEM) with Energy dispersive X-ray (EDX) spectroscopy. The cathode catalyst layers without and with carbon black additive were characterized by scanning electron microscopy, EDX, cyclic voltammetry and current-voltage curve measurements. Compared with Vulcan XC-72R and Black Pearls 2000, Ketjen Black EC 300J was more beneficial to increase the electrochemical surface area and DMFC performance of the cathode catalyst layer. The cathode catalyst layer with Ketjen Black EC 300J additive was kept intimately binding with the Nafion membrane after 360 h stability test of air-breathing DMFC.