Methanol Electrooxidation In Acidic Medium Research Articles

Three-Dimensional Graphene Aerogel Supported on Efficient Anode Electrocatalyst for Methanol Electrooxidation in Acid Media

This work attempted to improve the catalytic performance of an anodic catalyst for use in direct methanol fuel cells by coating graphene aerogel (GA) with platinum nanoparticles. A hydrothermal, freeze-drying, and microwave reduction method were used to load Pt–Ru bimetallic nanoparticles onto a graphene aerogel. The mesoporous structure of a graphene aerogel is expected to enhance the mass transfer in an electrode. XRD, Raman spectroscopy, SEM, and TEM described the as-synthesized PtRu/GA. Compared to commercial PtRu/C with the same loading (20%), the electrocatalytic performance of PtRu/GA presents superior stability in the methanol oxidation reaction. Furthermore, PtRu/GA offers an electrochemical surface area of 38.49 m2g−1, with a maximal mass activity/specific activity towards methanol oxidation of 219.78 mAmg−1/0.287 mAcm−2, which is higher than that of commercial PtRu/C, 73.11 mAmg−1/0.187 mAcm−2. Thus, the enhanced electrocatalytic performance of PtRu/GA for methanol oxidation proved that GA has excellent potential to improve the performance of Pt catalysts and tolerance towards CO poisoning.

Influence of different carbon and SnO2 ratios on the activity of PtIr/C (SnO2)1 catalysts toward methanol oxidation

• PtIr/C 0.40 (SnO 2 ) 0.60 nanowires showed enhanced catalytic activity toward methanol oxidation. • The synergy between C and SnO 2 as support results in a high catalytic performance. • The PtIr/C 0.40 (SnO 2 ) 0.60 catalyst displayed the lowest resistance to charge transfer. • The composition PtIr/C 0.40 (SnO 2 ) 0.60 is more stable than the other catalysts. • Different affinity between PtIr NWs and carbon or tin oxide results in different agglomeration of the NWs. PtIr nanowires (NWs) with a fixed ratio of 90% Pt and 10% Ir were supported in mixtures of Vulcan XC-72 R carbon and tin oxide (SnO 2 ) in the proportions of 50:50, 40:60, 30:70, 20:80, and 10:90 of carbon and SnO 2 . We successfully synthesized PtIr NWs by chemical reduction of the metallic precursors with formic acid and tested them toward methanol electro-oxidation in acidic media. Neither surfactants nor templates were used during the syntheses. The electrochemical study was conducted by CO-stripping, cyclic voltammetry, chronoamperometry, and steady-state polarization curves. The PtIr NWs have a higher affinity to be anchored onto the carbon support than on SnO 2 , resulting in different distribution and agglomeration of the NWs that thereby has substantial consequences on the catalytic activity of the composites. The PtIr/C 0.4 (SnO 2 ) 0.6 catalytic composite exhibited the highest activity toward methanol oxidation. The high catalytic performance displayed by the PtIr/C 0.4 (SnO 2 ) 0.6 composite results from the synergy between C and SnO 2 as supports (specifically in this proportion), Ir as the co-catalyst, and the morphology of the nanowires. Therefore, these combined effects result in greater mobility of OH ads and CO ads , facilitating the CO removal from the catalyst surface and allowing better methanol adsorption for further oxidation. The PtIr/C 0.4 (SnO 2 ) 0.6 catalyst also showed the lowest resistance to charge transfer compared with the other binary catalysts. Thus, the use of SnO 2 + C as supports and PtIr nanocatalysts with NW morphology results in highly active materials toward methanol oxidation, which are promising to compose anodes for direct methanol fuel cells.

One-step fabrication of a highly dispersed palladium nanoparticle-decorated reduced graphene oxide electrocatalyst for methanol electro-oxidation in acidic media

Reduced graphene oxide (RGO) was successfully decorated with homogeneous highly dispersed palladium nanoparticles (PdNPs) by a novel single-step hydrothermal-assisted formic acid reduction reaction without the use of any surfactants. The structure, surface morphology, and elemental composition of the as-prepared PdNP-RGO electrocatalyst were extensively characterized. The PdNP-RGO electrocatalyst demonstrated outstanding electrocatalytic activity (8.65 mA/cm2) toward the methanol oxidation reaction (MOR) in an acidic medium that is 1.4 times higher than PdNP-decorated Vulcan XC72 (6.2 mA/cm2) and also comparable with that of Pd-based electrocatalysts in alkaline media from the previous reports. Furthermore, the as-prepared PdNP-RGO electrocatalyst also shows remarkable stability performance for the MOR in an acidic medium and thus offer new insights into the processing method of an outstanding electrocatalyst at the anode electrode in the direct methanol fuel cell with reasonable cost, clean and facile synthesis approach.

Monodisperse Pt-Co/GO anodes with varying Pt: Co ratios as highly active and stable electrocatalysts for methanol electrooxidation reaction

The intense demand for alternative energy has led to efforts to find highly efficient and stable electrocatalysts for the methanol oxidation reaction. For this purpose, herein, graphene oxide-based platinum-cobalt nanoparticles (Pt100−xCox@GO NPs) were synthesized in different ratios and the synthesized nanoparticles were used directly as an efficient electrocatalyst for methanol oxidation reaction (MOR). The characterizations for the determination of particle size and surface composition of nanoparticles were performed by transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The structure of the catalysts was detected as face-centered cubic and the dispersion of them on graphene oxide was homogenous (distributed narrowly (4.01 ± 0.51 nm)). Cyclic voltammetry (CV) and chronoamperometry (CA) was utilized for testing electrocatalytic activities of all prepared NPs for the methanol oxidation reaction. It was detected that the newly produced NPs were more active and stable than commercially existing Pt(0)/Co nanomaterial in methanol electro-oxidation in acidic media.

A Novel Pt/WCx/C Electrocatalyst Synthesized by a One-Pot Method for Methanol Electrooxidation in Acid Media

A Novel Pt/WCx/C Electrocatalyst Synthesized by a One-Pot Method for Methanol Electrooxidation in Acid Media

High Methanol Electro-Oxidation Using PtCo/Reduced Graphene Oxide (rGO) Anode Nanocatalysts in Direct Methanol Fuel Cell.

The higher methanol utilization efficiency in direct methanol fuel cell (DMFC) is one of the key parameter to show the performance of an anode catalyst. Here in, we have synthesized a highly efficient and stable PtCo anode nanocatalysts (2-4 nm size) supported on reduced graphene oxide (rGO) for the electro-oxidation of methanol in a DMFC. Three different compositions of anode catalysts PtCo (1:7)/rGO, PtCo (1:9)/rGO and PtCo (1:11)/rGO comprising of 20% metal loading by weight of rGO are being investigated for methanol electro-oxidation in acidic medium with different methanol concentration using cyclic voltammetry. The electrochemical response from three different catalysts revealed that the PtCo (1:9)/rGO catalyst has efficiently oxidized 5 M methanol in a half cell configuration. A peak anodic current density of 46.8 mA/cm² and a power density of 136.8 mW/cm² are achieved using PtCo (1:9)/rGO anode catalyst at 100 °C for DMFC with 5 M methanol supply with negligible amount of methanol crossover. About 34% Faradaic efficiency and 22% energy efficiency is attained using PtCo (1:9)/rGO anode catalyst for a DMFC. Further, the 3% methanol oxidation reaction (MOR) efficiency is attained as revealed by evaluating the MOR by-products i.e., formic acid and formaldehyde formation. The results indicate excellent catalytic behavior of PtCo (1:9)/rGO towards MOR and its potential application as anode catalyst in DMFC.

Carbon-Supported Pt and Pt–Ir Nanowires for Methanol Electro-Oxidation in Acidic Media

Direct methanol fuel cells are promising electrochemical energy conversion devices. But, more efficient and stable and less expensive catalysts are still required. Here, we successfully synthesized Pt/C and Pt0.5–Ir0.5/C, Pt0.6–Ir0.4/C, Pt0.7–Ir0.3/C, and Pt0.8–Ir0.2/C nanowires by the chemical reduction of the metallic precursors by formic acid and tested them towards methanol electro-oxidation in acidic media. Neither surfactants nor templates were used during the syntheses. The nanowires catalysts were compared with a commercial state-of-art catalyst aiming the observation of the properties improvements derived from both alloying Pt with Ir and morphology change from nanoparticles to nanowires. Well-defined and slightly agglomerated over the carbon nanowires (diameters and lengths of approximately 5 and 20 nm, respectively) were obtained, the fact that is ascribed to the 40 wt% metal loading. In addition, accelerated degradation tests showed that Pt0.6–Ir0.4/C, Pt0.7–Ir0.3/C and Pt0.8–Ir0.2/C catalysts are more stable than commercial Pt/C. All synthesized nanowires catalysts were more active towards methanol electro-oxidation than the commercial Pt/C. The Pt0.5–Ir0.5/C sample shows Pt mass activities 7 times that of commercial Pt/C. However, the Pt0.8–Ir0.2/C catalyst presented the best specific activity (6 times that of commercial Pt/C), have the highest currents in the derivative voltammetry and the oxidation potential shifts negatively 100 mV in comparison with the commercial Pt/C catalyst. Hence, the nanowires developed in this study are indicated as potential promising catalysts and can be applied successfully as direct methanol fuel cell anodes.

Worm-like PtP nanocrystals supported on NiCo2Px/C composites for enhanced methanol electrooxidation performance

Worm-like PtP nanocrystals supported on NiCo2Px/carbon black (NiCo2Px/C) composites were prepared by a combined hydrothermal, low temperature phosphidation and NaBH4 reduction process. Noteworthily, the presence and content of phosphorus (P) play a critical role in constructing one-dimensional (1D) PtP nanostructures. Electrochemical tests demonstrate that the obtained PtP-NiCo2Px/C hybrid exhibits an extremely high mass activity of 1361 mA mg−1Pt for methanol electrooxidation in acidic medium, which is 3.5- and 7.6-fold greater than those of commercial Pt/C (393 mA mg−1Pt) and home-made Pt/C catalyst (180 mA mg−1Pt), respectively. Meanwhile, the catalytic performence of PtP-NiCo2Px/C is also better than those of the PtP-CoP/C and PtP-Ni2P/C catalysts due to the synergistic effect of Co and Ni. Furthermore, PtP-NiCo2Px/C catalyst exhibited better durability and CO tolerance compared with other catalysts in this study. The enhanced catalytic performence of PtP-NiCo2Px/C hybrid can be attributed to the special 1D morphology of PtP nanocrystals, the strong interaction between catalytic species and support, as well as the existence of metal center (Mδ+, M = Ni or Co) and Pδ− active sites for the dissociation of H2O molecules. The design of 1D PtP alloy nanostructures and co-catalytic effect of NiCo2Px provides a promising method to significantly improve methanol oxidation performence.

Comparative Study of PtCo/MNC and PtCo/Rgo As Anodic Electrocatalysts for Methanol Electro-Oxidation in Acid Medium

PtCo/MNC and PtCo/rGO as anodic electrocatalysts (20 wt% Pt loading) have been synthesized by non-sequential co-impregnation method and chemical reduction route using citric acid and Ar-H2 static atmosphere. Micro-/nano-structured carbon (MNC) sample was synthesized via nanocasting process with anhydrous pyrolysis at 800 °C using SBA-15 as hard template and refined sugar as carbon source. SBA-15 was prepared via sol gel using pluronic P-123 as surfactant. GO was prepared via Hummers modified method. The prepared materials were characterized by means of N2 physisorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and high resolution transmission electron microscopy (HRTEM). The performance of PtCo/MNC for methanol oxidation reaction (MOR) was measured by cyclic voltammetry (CV), chronoamperometry (CA). The electrochemical characterization techniques revealed that the mass activity of PtCo/MNC, PtCo/rGO and the commercial electrocatalyst PtRu/C at 20 cycles were 473, 322 and 300 mA/mgPt respectively as well as the carbon monoxide tolerance index ICO for these catalysts were 1.38, 1.56 and 0.93 respectively. PtCo/rGO exhibit better electrocatalytic performance, electrochemical stability and best resistance to carbonaceous intermediates species for the electro-oxidation of methanol.

Photo-electro synergistic catalysis: Can Pd be active for methanol electrooxidation in acidic medium?

Development of alternative Pt-free electrocatalyst for methanol oxidation reaction (MOR) in acidic medium remains a big challenge. As is reported, Pd is a good electrocatalyst for MOR in alkaline medium, but it is commonly recognized as inactive in acidic medium. Herein, we report an active Pd nanoparticles electrocatalyst for MOR in acidic medium although its catalytic activity is low. The photoexcitation of the plasmonic Pd nanoparticles leads to an MOR activity enhancement by a factor of 2 under visible light. Interestingly, the photogenerated electron-hole separation on nanosized TiO2 and the surface plasmon resonance effect of Pd nanoparticles on Pd/TiO2 heterostructure synergistically promote the photo-electrocatalytic activity of MOR under simulated solar light. The 17.9-fold activity enhancement of MOR in the presence of UV light indicates that the photogenerated electron-hole separation on TiO2 plays a crucial role in the photo-electro-synergistic methanol oxidation reaction. This remarkable light-driven activity enhancement of methanol oxidation reaction on Pd/TiO2 heterostructure suggests that the combination of plasmonic Pd nanoparticles and photogenerated electron-hole separation on TiO2 could provide a new strategy for the design and construction of energy conversion system.

Highly dispersed PtCo nanoparticles on micro/nano-structured pyrolytic carbon from refined sugar for methanol electro-oxidation in acid media

Abstract In this work, anodic electrocatalyst (20%wt of metal loading) as PtCo nanoparticles (atomic ratio of 48:52) on micro/nano-structured pyrolytic carbon (MNC) was synthesized by sequential impregnation method and chemical reduction route using citric acid and Ar-H2 static atmosphere. MNC sample was synthesized via nanocasting process with anhydrous pyrolysis at 800 °C using SBA-15 as hard template and refined sugar as carbon source. SBA-15 was prepared via sol gel using pluronic P-123 as surfactant and tetraethoxysilane as silica precursor. The prepared materials were characterized by means of N2 physisorption, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and high resolution transmission electron microscopy. The performance of PtCo/MNC for methanol oxidation reaction (MOR) was measured by cyclic voltammetry, chronoamperometry. The electrochemical characterization techniques revealed that the mass activity of PtCo/MNC and the commercial electrocatalyst Pt/C (20%wt of Pt loading) at 20 cycles were 481 and 372 mA/mgPt respectively as well as the resistance to the accumulation intermediate carbonaceous species (methoxy, aldehyde, formaldehyde and carbon monoxide) denoted by the ratio If/Ib for these catalysts were 1.30 and 0.76 respectively. PtCo/MNC exhibit better electrocatalytic performance, electrochemical stability and best resistance to carbonaceous intermediates species in the electro-oxidation of methanol.

Fabrication of bimetallic PtPd alloy nanospheres supported on rGO sheets for superior methanol electro-oxidation

Bimetallic PtPd nanospheres strongly fabricated on reduced graphene oxide (rGO) sheets (rGO-PtPd) by simple one pot wet reflux method for superior methanol electro-oxidation. There is no any other polymer or seed involved for preparation of nanocomposite. The as-synthesized materials structure and morphology was calibrated by Powdered X-ray diffraction (P-XRD), Raman, X-ray photo electron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The PtPd nanoparticles supported rGO sheets displays superior electro-catalytic activity and stability towards methanol electro-oxidation (MOR) because of their large electrochemical surface area (ECSA, which is 1.68 times greater than that of commercial Pt/C black) and synergistic effect of the bimetallic alloy. The rGO-PtPd showed enhanced electro-catalytic performances towards MOR in acidic media due to particle size and uniform distribution of particles, which rGO-Pt1Pd1 (Pt/Pd molar ratio 1/1) showed the more specific activity, mass activity and stability for MOR. Thus, as-synthesized rGO-PtPd catalyst could apply potential applications in direct methanol fuel cells (DMFCs) to lower their cost and advance their cycle ability, which make it promising for practical catalysis in energy conversion and storage.

Tailored Au and Pt Containing Multi-metallic Nanocomposites for a Promising Fuel Cell Reaction

The development of an efficient syntheses method to produce multimetallic nanocomposites with an appropriate structure is required to study the structure–composition–property relationship of the synthesized nanocomposites and to investigate, evaluate their possible technological applications. In this work, a fine hetero-structured Au and Pt containing multi-metallic nanocomposites (Au/Pt/Ag and Au/Pd/Pt colloidal nanocomposites) were synthesized through a microwave irradiation method with the use of trisodium citrate as a reducing agent and it has been coated on the glassy carbon electrode. It is characterized by high-resolution transmission electron microscopy, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopic techniques to elucidate structure, surface morphology, bulk-composition and metallic state of the resulting Au/Pt/Ag and Au/Pd/Pt colloidal nanocomposites respectively. The colloidal nanocomposites were also characterized by zeta potential and dynamic light scattering studies. The electrochemical techniques (cyclic voltammetry and chronoamperometry) have been employed to investigate the electrochemical parameters related to the electro-oxidation of methanol which in turn will be useful for conventional fuel cell applications. In addition to that, the density functional theoretical optimized minimum-energy structures of Pt n (n = 3–6) were studied as they are forming shell and thus involved in catalysis. Electronic density of state plots of the optimized Pt n and Pd n clusters using B3LYP/Lanl2DZ level of theory was made. The multi-metallic nanocomposites of these metals are proposed as a promising new class of catalyst for the electro-oxidation reaction of methanol particularly in fuel-cell applications. The formation of hetero-structure is discussed as the desirable condition to obtain a better electrocatalytic activity. It is also found that, the electrocatalytic activity and stability of the resultant Au/Pt/Ag colloidal nanocomposites modified glassy carbon electrode is much better catalyst towards methanol electrooxidation in acid medium.

CeO2-modified α-MoO3 nanorods as a synergistic support for Pt nanoparticles with enhanced COads tolerance during methanol oxidation.

A new type of Ce-doped α-MoO3 (Ce0.2Mo0.8O3-δ) nanorod support was synthesized using a two-step hydrothermal method. The mixed oxide solid solution was employed as a novel non-carbon support for Pt catalysts used for the methanol electrooxidation in acidic media. The ratio of Ce to Mo in the solid-solution was systematically optimized in terms of the performance as a support for methanol oxidation. Pt nanoparticles with an average diameter of 2 nm were evenly deposited on Ce0.2Mo0.8O3-δ nanorods. Compared to the Pt/MoO3 and commercial Pt/C catalysts, the optimal Pt/Ce0.2Mo0.8O3-δ catalyst exhibited significantly enhanced COads tolerance during the methanol oxidation, thereby yielding the highest electrocatalytic activity and stability. The improved electrochemical performance can be ascribed to strengthened metal-support interactions derived from the high number of oxygen vacancies on Ce0.2Mo0.8O3-δ along with its unique one-dimensional nanorod structure. In addition, these findings suggest that the doping-induced structural and size transition of MoO3 could provide a new pathway to develop doped oxides capable of providing sufficient electrical conductivity and possible synergistic effects with other active components for electrocatalysis applications.

Erratum to: Effect of wetted graphene on the performance of Pt/PPy-graphene electrocatalyst for methanol electrooxidation in acid medium

Polypyrrole (PPy)-modified graphene can be used as a support of electrocatalyst in methanol oxidation reaction. In this paper, the Pt/PPy-graphene electrocatalyst is prepared through in situ synthetic method. The structure and electrochemical property of the electrocatalyst were investigated. The results show that the ultrathin water film between graphene and PPy was favorable as the PPy was distributed uniformly on the upper surface of graphene. The PPy-modified graphene enables the formation of Pt nanoparticles having a very narrow size profile centered around 8 nm and a very even spatial distribution on the graphene surface. The Pt/PPy-graphene catalyst exhibits a noticeably higher electrochemical activity in methanol oxidation reaction and performance durability than the Pt/graphene catalyst, and thus, PPy-graphene is a promising alternative catalyst support in direct methanol fuel cells.

Facile Synthesis of Bimetallic Au@Pd Nanoparticles with Core-shell Structures on Graphene Nanosheets

In this paper, we report a simple one-step thermal reducing method for synthesis of bimetallic [email protected] nanoparticles with core-shell structures on the graphene surface. This new type of [email protected]–G composites is characterized by transmission electron microscopy, high resolution transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction. It is found that [email protected] nanoparticles with an average diameter of 11 nm are well dispersed on the graphene surface, and the Au core quantity as well as the Pd shell thickness can be quantitatively controlled by loading different amounts of metallic precursors, and the involved core-shell structure formation mechanism is also discussed. The ternary Pt/[email protected]–G composites can also be synthetized by the subsequent Pt doping. The catalytic performance of [email protected]–G composites toward methanol electro-oxidation in acidic media is investigated. The results show that [email protected]–G composites exhibit higher catalytic activity, better stability and stronger tolerance to CO poisoning than Pd–G and Au–G counterparts.

Ce0.8Sn0.2O2−δ–C composite as a co-catalytic support for Pt catalysts toward methanol electrooxidation

Ce0.8Sn0.2O2−δ solid solution is fabricated using a simple one-step solvothermal method. The synthesized solid solution mixed with Vulcan XC-72 carbon black (denoted by Ce0.8Sn0.2O2−δ–C) is employed as a co-catalytic support for Pt catalysts toward methanol electrooxidation. X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, N2 adsorption/desorption and temperature programmed reduction (TPR) are used to characterize the properties of Ce0.8Sn0.2O2−δ solid solution. The results show that Ce0.8Sn0.2O2−δ possesses a high specific surface area, an enhanced conductivity and a high oxygen storage capacity (OSC). Pt catalysts grown around Ce0.8Sn0.2O2−δ on carbon black form a special Pt–Ce0.8Sn0.2O2−δ–C triple junction structure, and their electrocatalytic properties are investigated in detail by a series of electrochemical methods. As compared with Pt/CeO2–C and commercial Pt/C catalysts, Pt/Ce0.8Sn0.2O2−δ–C catalyst exhibits superior electrocatalytic activity and long-term stability for methanol electrooxidation in acid media. The origin of the enhanced electroctatlytic properties for Pt/Ce0.8Sn0.2O2−δ–C is closely related to the OSC of Ce0.8Sn0.2O2−δ and the triple junction structure.

Electrochemical activity and stability of core–shell Fe2O3/Pt nanoparticles for methanol oxidation

Core–shell Fe2O3/Pt nanoparticles with amorphous iron oxide cores are successfully synthesized by a two-step chemical reduction strategy. The Pt loading can be adjusted using this preparation technique to obtain a series of chemical compositions with varying amounts of Pt precursors. The morphology, structure, and composition of the as-prepared nanoparticles are characterized by transmission electron microscopy, X-ray diffraction, energy dispersive spectroscopy, and X-ray photoelectron spectroscopy. Electrocatalytic characteristics are systematically investigated by electrochemical techniques, such as cyclic voltammetry, chronoamperometry, and in situ Fourier transform infrared spectroscopy. Compared with the E-TEK 40 wt% Pt/C catalyst, the as-made Fe2O3/Pt nanoparticles exhibit superior catalytic activity with lower peak potential and enhanced CO2 selectivity toward methanol electrooxidation in acidic medium. The highest activity is achieved by core–shell Fe2O3/Pt nanoparticles with a Fe/Pt atomic ratio of 2:1 (A g−1 of Pt) or 3:1 (mA cm−2). These nanomaterials also show much higher structural stability and tolerance to the intermediates of methanol oxidation. Methanol electrooxidation reactions with higher performance can be achieved using core–shell nanoparticles with an amorphous iron oxide core and minimum Pt loading.

Single-walled carbon nanotube buckypapers as electrocatalyst supports for methanol oxidation

This work studies the use of various single-walled carbon nanotube (SWCNT) buckypapers as catalyst supports for methanol electro-oxidation in acid media. Buckypapers were obtained by vacuum filtration from pristine and oxidized SWCNT suspensions in different liquid media. Pt–Ru catalysts supported on the buckypapers were prepared by multiple potentiostatic pulses using a diluted solution of Pt and Ru salts (2 mM H2PtCl6 + 2 mM RuCl3) in acid media. The resulting materials were characterized via SEM, TEM, EDX and ICP-OES analysis. Well dispersed rounded nanoparticles between 2 and 15 nm were successfully electrodeposited on the SWCNT buckypapers. The ruthenium content in the bimetallic deposits was between 32 and 48 at. %, while the specific surface areas of the catalysts were in the range of 72–113 m2 g−1. It was found that the solvent used to prepare the SWCNT buckypaper films has a strong influence on the catalyst dispersion, particle size and metal loading. Cyclic voltammetry and chronoamperometry experiments point out that the most active electrodes for methanol electro-oxidation were prepared with the buckypaper supports that were obtained from SWCNT dispersions in N-methyl-pyrrolidone.

Methanol electrooxidation on synthesized PtRu nanocatalyst supported on acetylene black in half cell and in direct methanol fuel cell

We reported the direct reduction of H2PtCl6 and RuCl3 solution containing acetylene black powder by Na2S2O4 to make Pt–Ru (20–10 wt%) supported on acetylene black (Pt–Ru/AB) as a nanocatalyst for methanol electrooxidation in acidic media. The electrochemical activity of catalyst was studied by electrochemical impedance spectroscopy, linear sweep voltammetry, cyclic voltammetry and chronoamperometry. Structural aspects of the Pt–Ru (20–10 wt%)/AB were studied by transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques. The analysis of electrochemical results indicated lower charge transfer resistance, higher peak current for Pt–Ru (20–10 wt%)/AB compared to the commercial catalyst, Pt–Ru (20–10 wt%)/carbon Vulcan. XRD spectra verified a face centered cubic structure for the synthesized Pt–Ru/AB and its particle size was mostly 10 nm according to TEM and XRD images. In DMFC, Pt–Ru/AB had superior performance compared to the commercial catalyst in all current densities, which could be attributed to enhancement of the methanol oxidation kinetics, higher conductivity, and more uniform distribution of the ionomer in anode catalyst layer.