Ethanol In Alkaline Media Research Articles

Synthesis of Pt-Au nanoparticles supported on reduced graphene oxide as a highly active and durability catalyst for electro-oxidation of ethanol

Design of advanced electrocatalyst, with high active and stability in electro-oxidation reactions for Direct Alcohol Fuel Cells system is urgent scientific need in the context of electrochemical energy application. Herein, Pt-Au nanoparticles supported on reduced graphene oxide, with low content of metals (With the theoretical content of 1.87% (Au) and 4.67% (Pt)), as a highly active and durability catalyst for electro-oxidation of ethanol is successfully synthesized. The current density (mass specific activity) of the PtAu/rGO catalyst for electro-oxidation ethanol, in alkaline media, was 13195 mAmgPt-1, which is 1.26 times higher than that of the Pt/rGO catalyst. After 4000s, the current density of PtAu/rGO catalyst reached 317 mAmgPt-1, is higher than that of Pt/rGO catalyst, reaching 172 mAmgPt-1. The high catalytic activity and stability of the bimetallic PtAu/rGO catalyst in the electrochemical oxidation of ethanol in alkaline medium are attributed to the synergistic effect of Au, Pt and rGO, among which, Au not only plays the role of enhancing the dispersion of Pt, but also has the effect of preventing the agglomeration of Pt nanoparticles during the reaction. This research could open up the potential to develop advanced bimetallic PtAu materials that can be used as electrochemical catalysts for various reactions.

Design and Synthesis of Palladium/Black Phosphorus–Graphene Hybrids as High-Performance Catalysts for Ethanol Electrooxidation in Alkaline Media

In this study, a series of Pd-supported black phosphorus–graphene (Pd/BP-G) catalysts are prepared to explore their electrocatalytic performances in the electrooxidation of ethanol in alkaline media. The characterization results show that BP is combined with activated graphene to form a P–C bond and a P–O–C bond heterojunction. Pd nanoparticles equally anchor on the BP-G hybrid, and Pd/BP-G exhibited enhanced electrocatalytic activity for the ethanol oxidation reaction in alkaline media. The electrochemically active surface area and mass activity for the Pd/BP-G catalyst reached 210.4 m2·gPd–1 and 3960.0 mA·mgPd–1, which are 9.54 and 5.86 times higher than those of commercial Pd/C, respectively. Further studies show that Pd/BP-G catalysts have reliable stabilities and faster reaction kinetics. These results indicate that the prepared Pd/BP-G catalysts have great application potentials in direct ethanol fuel cells.

Pd-Ni-B/C Nanocatalysts for Electrochemical Oxidation of Ethanol in Alkaline Media

This paper describes the synthesis of Pd<sub>0.70</sub>-Ni<sub>x</sub>-B<sub>y</sub> nanoparticles (x:y = 0.30:0, 0:0.30, 0.25:0.05, 0.20:0.10, 0.15:0.15, and 0.10:0.20) supported on carbon Vulcan XC-72 R by the chemical reduction method using ethylene glycol as a reducing agent for the study of the electrochemical oxidation of ethanol in alkaline media. Neither surfactants nor templates were used during the syntheses. The catalysts were physically characterized by transmission electron microscopy that showed the formation of nanoparticles with diameters of approximately 3 nm. Analyses of X-ray dispersive energy spectroscopy coupled with scanning electron microscopy identified the presence of the synthesized metals in concentrations close to the nominal ones. The electrochemical study was performed by CO-stripping, cyclic voltammetry, chronoamperometry, and steady-state polarization curves. The catalytic efficiency was also evaluated against the oxidation of CO, which is the principal intermediate adsorbed on the surface of catalysts during ethanol oxidation. The Pd<sub>0.70</sub>Ni<sub>0.15</sub>B<sub>0.15</sub>/C catalyst showed the lowest oxidation onset potentials for both CO (0.37 V) and ethanol oxidation (0.51 V) compared with the Pd/C catalyst (0.63 V and 0.64 V). Chronoamperometric tests also revealed that the Pd<sub>0.70</sub>Ni<sub>0.15</sub>B<sub>0.15</sub>/C catalyst displayed current densities four times higher than those of the Pd/C catalyst, probably because of the electronic and geometric effect that favors the removal of intermediate species from the catalyst surface. The synthesized ternary catalysts were more efficient toward the electrochemical oxidation of ethanol in alkaline media than Pd<sub>0.7</sub>Ni<sub>0.3</sub>/C and Pd/C catalysts. Thus, the synergistic effect of boron on the structure of binary nanoparticle catalysts supported on carbon for use in direct alcohol fuel cells was demonstrated for the first time.

Insights into the origin of the enhanced electrical conductivity of Pd-Sb2O3 nanoparticles: A combined experimental and theoretical study

Supported metal nanocrystallites play a paramount role in catalysis, electrocatalysis, and gas sensing, among other fields. Although the majority of studies are focused on the modification of the composition, size and morphology of the active metallic phase to meet specific needs, the influence of the properties of the support on the overall behavior of such materials is often neglected. In a previous publication, we described for the first time the use of antimony trioxide (Sb2O3) as a new support material for Pd nanoparticles for the electrochemical oxidation of ethanol in alkaline media. Despite its high catalytic activity, information for the intrinsic fundamental properties of Pd-Sb2O3, such as the electrical conductivity and presence of defects, is still lacking. In this work, we combined both experimental techniques and theoretical simulations to gain further knowledge into some relevant physicochemical properties of the Pd-Sb2O3 system. An increase in electrical conductivity of 1000x is found in the Sb2O3 phase after the deposition of a small amount (4.9% weight) of Pd, which cannot be explained by the metallic phase; rather, oxygen vacancies in the Sb2O3 (as indicated by photoluminescence experiments) are likely the origin of such behavior. Theoretical calculations performed by density functional theory show that oxygen vacancies not only lead to distortion in chemical bonds but also change the overall reactivity of the system, corroborating X-ray photoelectron spectroscopy and electrochemical experiments.

Ag-MnxOy on Graphene Oxide Derivatives as Oxygen Reduction Reaction Catalyst in Alkaline Direct Ethanol Fuel Cells

In this study, Ag-MnxOy/C composite catalysts deposited on reduced graphene oxide (rGO) and, for the first time on N-doped graphene oxide (NGO), were prepared via a facile synthesis method. The influence of the carbon support material on the activity and stability of the oxygen reduction reaction (ORR) and on the tolerance to ethanol in alkaline medium was focused and investigated. The physicochemical properties of the Ag-MnxOy/C catalysts were analyzed by X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), Brunauer–Emmett–Teller (BET) method, atomic absorption spectroscopy (AAS), inductively coupled plasma-mass spectrometry (ICP-MS), and thermogravimetric gas analysis (TGA). Electrochemical characterization was performed by rotating disk electrode (RDE) experiments. The results show that the active manganese species MnO2 was assembled as nanorods and nanospheres on rGO and NGO, respectively. Ag was assumed to be present as very small or amorphous particles. Similar redox processes for Ag-MnxOy/rGO and Ag-MnxOy/NGO were examined via cyclic voltammetry. The Ag-MnxOy/rGO resulted in a more negative diffusion limiting current density of −3.01 mA cm−2 compared to Ag-MnxOy/NGO. The onset potential of approximately 0.9 V vs. RHE and the favored 4-electron transfer pathway were independent of the support material. Ag-MnxOy/NGO exhibited a higher ORR stability, whereas Ag-MnxOy/rGO showed a better ethanol tolerance.

Electro-Catalytic Properties of Palladium and Palladium Alloy Electro-Catalysts Supported on Carbon Nanofibers for Electro-Oxidation of Methanol and Ethanol in Alkaline Medium

Carbon nanofibers (CNFs) supported by Pd and Pd-Sn electro-catalysts were prepared by the chemical reduction method using ethylene glycol as the reducing agent. Their physicochemical characteristics were studied using high resolution-transmission electron microscopy (HR-TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and Bruanaer-Emmett-Teller (BET) analysis. FTIR revealed that oxygen, hydroxyl, carboxylic and carbonyl functional groups facilitated the dispersion of Pd and Sn nanoparticles. The doping of Pd with Sn to generate PdSn alloy was also confirmed by XPS data. The amorphous nature of CNFs was confirmed by XRD patterns which exhibited the Pd diffraction peaks. When Sn was added to Pd/CNFs, the diffraction peaks moved to lower angles. HRTEM images revealed that the CNFs with cylindrical shape-like morphology and also Pd-Sn nanoparticles dispersed on carbon support. The catalytic activity and stability towards alcohol electro-oxidation in alkaline medium at room temperature was evaluated using cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). The obtained Pd-Sn/CNFs electro-catalyst exhibited a better electro-catalytic activity than Pd/CNFs and Pd/C electro-catalysts for both methanol and ethanol oxidation. The improvement of the electrochemical performance was associated with the synergistic effect via the addition of Sn which modified the Pd atom arrangement, thereby promoting oxidation through a dehydrogenation pathway. Furthermore, SnO2 generates abundant OH species which helps with increasing the rate of the oxidative removal of carbon monoxide (CO) intermediates from Pd sites.

Electrochemical reforming of ethanol with acetate Co-Production on nickel cobalt selenide nanoparticles

The energy efficiency of water electrolysis is limited by the sluggish reaction kinetics of the anodic oxygen evolution reaction (OER). To overcome this limitation, OER can be replaced by a less demanding oxidation reaction, which in the ideal scenario could be even used to generate additional valuable chemicals. Herein, we focus on the electrochemical reforming of ethanol in alkaline media to generate hydrogen at a Pt cathode and acetate as a co-product at a Ni1-xCoxSe2 anode. We first detail the solution synthesis of a series of Ni1-xCoxSe2 electrocatalysts. By adjusting the Ni/Co ratio, the electrocatalytic activity and selectivity for the production of acetate from ethanol are optimized. Best performances are obtained at low substitutions of Ni by Co in the cubic NiSe2 phase. Density function theory reveals that the Co substitution can effectively enhance the ethanol adsorption and decrease the energy barrier for its first step dehydrogenation during its conversion to acetate. However, we experimentally observe that too large amounts of Co decrease the ethanol-to-acetate Faradaic efficiency from values above 90% to just 50 %. At the optimized composition, the Ni0.75Co0.25Se2 electrode delivers a stable chronoamperometry current density of up to 45 mA cm−2, corresponding to 1.2 Ag−1, in a 1 M KOH + 1 M ethanol solution, with a high ethanol-to-acetate Faradaic efficiency of 82.2% at a relatively low potential, 1.50 V vs. RHE, and with an acetate production rate of 0.34 mmol cm−2h−1.

Synthesis of Branched Au‐PdAg Hybrid Nanosheets by Controlled Reduction in a Galvanic Replacement Reaction

AbstractWe report a niche strategy to fabricate planar trimetallic nanocrystals with in‐plane branches and a unique hybrid structure. The success of current work relies on the use of seeded growth to produce Au@Ag core‐shell nanocubes, followed by the reaction with an excessive third metal precursor (i. e., Pd) via galvanic replacement reaction (GRR) in the presence of controlled reduction. The morphology of resulting products varied in the order of cube, concave cube, hollow cage, yolk‐shell frame, and finally branched nanoplates with Au‐PdAg hybrid structure. The controlled reduction involved in the GRR process, together with the use of Au seed at appropriate amounts and docosyltrimethylammonium chloride as the capping agent, is demonstrated to be crucial for the formation of such unique structure. When loaded on carbon black and working as electrocatalysts for electroxidation of ethanol in alkaline media, the current products exhibit satisfying electrocatalytic activity (e. g., 591 mA mgPd−1 in mass activity and 10.01 A m−2 in specific activity), improved kinetics, and long‐term durability, as compared to commercial Pt/C. The present study offers a feasible route to applying precise spatial control over elemental metals for two‐dimensional dendritic noble metal nanocrystals and could be potentially extended to other metals or alloy.

Effect of palladium on gold in core-shell catalyst for electrooxidation of ethanol in alkaline medium

In this paper the effect of small amounts of palladium deposited on gold nanoparticles supported on Vulcan XC-72 carbon (core-shell structure denoted Au@Pd/C) is studied. Different nominal atomic compositional ratios of Au@Pdx maintaining fixed gold nuclei and varying the amount of palladium (x = 0.10; 0.80 and 1.60) were synthesized via seed growth method for the ethanol oxidation reaction in alkaline medium. UV–Vis spectrometric, X-ray powder diffraction, X-ray energy dispersive spectroscopy, transmission electron microscopy and electrochemical measurements were performed for the characterization of these catalysts. Electrocatalytic activity toward ethanol oxidation on Au@Pd/C catalysts were investigated by cyclic voltammetry and chronoamperometry showed that Au@Pd0.10/C electrocatalyst has the highest current density and low onset potential for ethanol oxidation reaction in alkaline medium. In-situ Fourier transform infrared spectroscopy measurements demonstrated that acetate is the main product of ethanol oxidation and CO2 can be slightest observed, the latter could be visualized in greater quantity on catalyst Au@Pd0.80/C catalyst.

The dual role of the surface oxophilicity in the electro-oxidation of ethanol on nanostructured Pd/C in alkaline media

• Pd/C electrocatalysts are used for amperometric sensors and also for Fuel Cells. • Size-induced effects on Pd/C resulted in distinct tendency to interact with oxygen. • Electrocatalytic activity towards ethanol oxidation depends on the surface oxophilicity. • PdO acts both as a promoter and/or inhibitor towards ethanol oxidation. • The catalytic activity can be enhanced by 57% only by varying surface oxophilicity. The ability of a surface to interact with oxygen (oxophilicity) plays a very important role in several catalytic, electroanalytic and electrocatalytic reactions. To date, however, the role of the oxophilicity in the electrochemical oxidation of ethanol was never shown for pure nanostructured Pd electrocatalysts supported on carbon, a promising material to be used as a non-enzymatic amperometric sensors for ethanol and also as an electrocatalyst for the Direct Ethanol Fuel Cells. In this work, Pd nanoparticles were prepared by chemical reduction at room temperature in the presence of varying amounts of sodium citrate in order to produce particles with distinct sizes. Then, we used cyclic voltammetry in 0.1 mol L -1 KOH to obtain an oxophilicity trend among various nanostructured Pd/C samples. The oxidation of ethanol in alkaline media demonstrated that the surface oxophilicity has a dual role in the kinetics of the reaction: a promoter at low and medium oxygen coverages, and a spectator (inhibitor) species at high surface coverages. Thus, by a proper control of the surface oxophilicity the current density at a constant potential can be enhanced by 57%, highlighting the importance of that parameter in the electro-oxidation on ethanol on Pd-based materials. Our results have a great impact for the design of more active non-enzymatic ethanol sensors and also for the development of more active electrocatalysts for Direct Ethanol Fuel Cells.

Facile synthesis of branched Au nanocrystals with sub-10-nm arms and their applications for ethanol oxidation reaction

Branched Au nanocrystals with sub-10-nm arms are synthesized via a one-pot reduction in aqueous phase. The success of current work relies on the use of octadecyltrimethylammonium chloride as the shape-directing capping agent to facilitate the formation of branched products in high purity. Their overall size could be controlled in the range of 16–60 nm by varying the Au precursor amount or concentration of capping agent, and the diameter of arms is limited to sub-10-nm size range. Interestingly, Au nanocrystals with a unique morphology, sheet-wrapped dendrites, could be obtained when the concentration of a reductant was varied. The current strategy is also validated effective in the fabrication of dendritic products composed of other noble metals or alloys in addition to Au by simply using the alternative metal precursor. As compared to spherical counterparts, the current branched Au nanocrystals exhibited noticeable red-shift in UV-Vis extinction spectrum and enhanced catalytic activities for electrooxidation of ethanol in alkaline media.

Superior ethanol electrooxidation activity of Pd supported on Ni(OH)2/C. The effect of Ni(OH)2 nanosheets content

This paper describes the synthesis of Pd nanoparticles supported on Ni(OH) 2 /C with different proportions of Pd:Ni(OH) 2 (30:70, 50:50, 70:30) and their catalytic activity towards the oxidation of ethanol in alkaline media. The catalysts are synthesised by a simple chemical reduction method. Electrochemical measurements show that Pd/Ni(OH) 2 /C catalysts with 30% of Ni(OH) 2 nanosheets content yield the highest catalytic activity towards ethanol oxidation, exhibiting the highest mass activity of 8452.8 mA mg −1 , which is 5-fold higher than at pure Pd catalyst. Additionally, electrochemical impedance spectra reveal lower values of charge transfer resistance for Pd 70 /Ni(OH) 2(30) /C. The Pd 70 /Ni(OH) 2(30) /C catalyst also displays excellent durability and stability during ethanol oxidation studied by chronoamperometric and cycling tests, reaching current densities almost six times higher than the Pd/C catalyst. The superior catalytic performance of the bimetallic Pd 70 /Ni(OH) 2(30) /C catalyst can result from the synergy between the metals. • Ni(OH) 2 nanosheets promoted the electrocatalytic performance of Pd nanoparticles. • Pd x /Ni(OH) 2( y ) catalysts were synthesised by a simple chemical reduction method. • Catalytic activity towards ethanol oxidation depends on the proportion of Pd:Ni(OH) 2. • Pd 70 /Ni(OH) 2(30) /C exhibited the highest catalytic activity towards ethanol oxidation.

Improved ethanol electro-oxidation at Ni@Pd/C and Ni@PdRh/C core–shell catalysts

This paper describes the synthesis and catalytic activity of carbon-supported Pd/C, PdNi/C, and PdNiRh/C catalysts with core–shell morphologies towards the oxidation of ethanol in alkaline media. The catalysts are synthesised by a chemical reduction method using sodium borohydride as the reducing agent. Electrochemical characterisations show that the addition of Ni and Rh enhances remarkably the electrocatalytic activity of the materials due to the bifunctional and electronic effects in PdNi/C and PdNiRh/C catalysts, and the synergetic effect of the bifunctional and core–shell morphology on the Ni@Pd/C and Ni@PdRh/C catalysts. Electrochemical impedance spectra reveal lower values of charge transfer resistance for Pd60Ni20Rh20/C and Ni20@Pd60Rh20/C. Chronoamperometric tests also reveal the Ni20@Pd60Rh20/C catalyst displays current densities 9.3 times higher than the Pd/C catalyst. The superior catalytic performance of the trimetallic core–shell Ni20@Pd60Rh20/C catalyst can result from the synergy between the metals and the presence of core–shell morphology.

Excellent electro-oxidation of methanol and ethanol in alkaline media: Electrodeposition of the NiMoP metallic nano-particles on/in the ERGO layers/CE

Here, the Ni-based metallic nano-particles (Ni, NiMo and NiMoP) were electrodeposited on/in the surface of ERGO/CE substrate from a citrate-based electrolyte and their catalytic activities investigated towards methanol and ethanol electro-oxidation. The physicochemical characterizations of all prepared electrocatalysts were investigated by different electrochemical and non-electrochemical techniques. The electrocatalytic activities of the modified electrodes towards the electro-oxidation of methanol and ethanol were studied in 0.1 M NaOH solution by conventional electrochemical methods such as cyclic voltammetry and chronoamperometry. In the optimized electrodeposition conditions, the obtained electrochemical results indicate that the NiMoP/ERGO/CE displays dramatically improved electrocatalytic activity [Jpf (mA.cm−2) = 263.14 for methanol and Jpf (mA.cm−2) = 253.35 for ethanol], stability and poisoning tolerance towards the electro-oxidation of these fuels in alkaline solution. Finally, for comparison, the Ni (alone) and NiMo (binary) electrodeposited on/in the ERGO/CE (without P) and also studying the influence of the ERGO layers on the surface of CE, the NiMoP/CE (without ERGO) were prepared and applied as electrocatalysts.

Nanoporous gold-palladium: A binary alloy with high catalytic activity for the electro-oxidation of ethanol

Abstract Nanoporous gold (NP–Au) is a promising versatile material that can be used in many fields due to its high conductivity, large surface area, and excellent stability. NP-Au is commonly functionalized by adding or doping other materials. However, difficult functionalizing procedures are oftentimes obstacles towards catalyst development. Herein, a simple method for alloying nanoporous gold with palladium (NP–AuPd) with a tunable Au/Pd ratio is developed. Ternary alloy films of Au–Pd–Mg are prepared by sputter deposition and Mg is dissolved from the alloy to make nanoporous alloy structures. The Au and Pd in NP-AuPd are evenly distributed over the entire structure. The catalytic activity of the developed NP-AuPd is evaluated by oxidizing ethanol in alkaline media. The optimized NP-AuPd shows remarkable catalytic activity and excellent stability. The nanoporous structure not only increases the number of reaction sites and mass transfer, but it also enhances the durability of the catalyst. The developed method can be extended to the preparation of binary nanoporous thin films with controlled compositions and desired catalytic activities.

Facile one-step room temperature synthesis of PdAg nanocatalysts supported on multi-walled carbon nanotubes towards electro-oxidation of methanol and ethanol

Pd nanocatalysts still suffer from poor activity and rapid stability degradation due to incomplete oxidation reaction of methanol and ethanol. Herein, we report the facile synthesis of bimetallic PdAg supported on multi-walled carbon nanotube (MWCNT) nanocatalysts prepared via one-step room temperature chemical reduction strategy without additional of any capping agents towards the electrooxidation of methanol and ethanol in alkaline medium. During the synthesis process, reduction reaction between PdCl2, AgNO3 and NaBH4 led to bimetallic PdAg/MWCNT electrocatalysts. The results revealed that the PdAg NPs are uniformly-dispersed on the surface of MWCNT with a well-defined structure, small particle size (5.5 nm) and high surface active area (117.49 m2gPd−1). XPS results showed a strong charge transfer interaction between Pd and Ag atoms on catalytic surface. Cyclic voltammetry (CVs) results demonstrate that as-obtained PdAg/MWCNT electrocatalysts exhibit higher electrochemical activity and long-term durability for methanol and ethanol oxidation than the Pd/C (JM) electrocatalysts. Moreover, Pd3·5Ag/MWCNT electrocatalyst exhibit higher electrochemical performance in ethanol (3722mA mgPd−1) than methanol (1619.52 mA mgPd−1). This method has shown promising effect as advance strategy for the synthesis of low cost and high-performance Pd-based nanocatalysts, and for large-scale application as well.

Insights on the electrooxidation of ethanol with Pd-based catalysts in alkaline electrolyte

In this work, we report a facile method of synthesis of carbon supported Pd, PdRu, and PdNi nanoparticles, and a comparative study of their catalytic behavior for the electrooxidation of ethanol in alkaline media. The addition of metals such as Ru or Ni increases the oxophilicity of the Pd surface, as observed from the shifting of the Pd oxide reduction peaks. As a consequence, the onset potential for the electrooxidation of ethanol shifts to less positive values on the bimetallic catalysts. The nature and evolution of the species formed during the electrooxidation of ethanol over the catalysts under study has been monitored using in situ infrared spectroscopy. In order to assess properly the evolution of the species formed during the electrooxidation of ethanol, infrared spectra have been recorded in both H2O and D2O electrolytes. The results presented in this work demonstrate that the scission of the C–C bond of ethanol takes place at the surface of Pd/C and PdM/C (M = Ni and Ru) at potentials as low as 30 mV. However, at potentials above E ≥ 400 mV, acetates are the main species formed during the electrooxidation of ethanol.

Optimization of the catalytic support and membrane for the electrochemical reforming of ethanol in alkaline media

AbstractBACKGROUNDIn this work, the influence of the anodic catalyst carbonaceous support and the membrane on the electrochemical reforming of ethanol for hydrogen production in alkaline media has been studied. Physicochemical characterization and electrochemical activity measurements were performed for different palladium‐based anodic catalysts. The best anodic catalyst was scaled up to two different membrane electrode assemblies (MEAs) based on anion exchange membranes (AEMs): Tokuyama and KOH‐doped polybenzimidazole (PBI) membranes. In both systems, the influence of the temperature and the stability were evaluated for the electrochemical reforming of ethanol.RESULTSAmong the different investigated catalysts, palladium supported on non‐functionalized low‐surface nanofibers was the best anodic catalyst for the electrochemical reforming of ethanol in alkaline media, which was attributed to the specific physicochemical and textural properties of this material. In addition, the use of a Tokuyama membrane allowed to obtain the highest electrocatalytic activity in hydrogen production together with a suitable stability behavior. Under the optimized conditions, current density values up to 120 mA cm−2 at 1.4 V were obtained, leading to lower energy values for hydrogen production compared with those of water electrolysis in commercial alkaline electrolyzers.CONCLUSIONThe choice of palladium supported on non‐functionalized nanofibers as anodic catalyst and a Tokuyama membrane allows to obtain the best MEA configuration for the electrochemical reforming of ethanol for hydrogen production. © 2019 Society of Chemical Industry

Facile synthesis of AuPd nanowires anchored on the hybrid of layered double hydroxide and carbon black for enhancing catalytic performance towards ethanol electro-oxidation

Improving the catalytic performance of ethanol electro-oxidation reaction (EOR) is crucial for accelerating the commercialization of direct ethanol fuel cells (DEFCs). In this work, AuPd nanowires (NWs) anchored on the hybrid of layered double hydroxides and carbon black (CB) was prepared by a facile procedure for anode electrocatalyst of ethanol electro-oxidation reaction (EOR). For comparison, unloaded AuPd NWs and AuPd nanopaticles (NPs) supported on LDH-CB were also prepared. These catalysts were characterized via X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The performance of these catalysts was evaluated by the reactions of ethanol in alkaline media by cyclic voltammetry, chronoamperometric measurements and electrochemical impedance spectroscopy. It was found that the as-prepared AuPd NWs/LDH-CB demonstrated higher activity and stability than those of unloaded AuPd NWs, commercial Pd/C and AuPd NPs/LDH-CB attributed to the AuPd nanowires with more active sites, electronic structure of Pd modified by alloyed with Au and interacted with LDH-CB as well as the electron transfer ability facilitated by CB.

Facile synthesis of ZnTe/Quinhydrone nanocomposite as a promising catalyst for electro-oxidation of ethanol in alkaline medium

In this work, we introduce a novel ZnTe/quinhydrone (ZnTe/QH) nanocomposite as an excellent catalyst for electro-oxidation of ethanol in alkaline medium. The ZnTe semiconductor nanorods were synthesized by a novel chemical route. The synthesized product was characterized by field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), FT-IR spectroscopy, and cyclic voltammetry techniques. Then, this product along with quinhydrone were used for the electrocatalytic oxidation of ethanol in alkaline medium. The ZnTe/QH/GCE showed a higher electrocatalytic activity toward ethanol oxidation. The performance of catalyst was evaluated by electrochemical measurements such as cyclic voltammetry and electrochemical impedance spectroscopy using the three-electrode system. Furthermore, the ZnTe/QH/GCE displayed a higher stability with 93% retention of the initial current density after 6000 s in long term current-time curve. This newly prepared ZnTe/QH nanohybrid could be a promising anodic catalyst for the direct ethanol fuel cells (DEFCs) application.