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[Display omitted] • ·Mo 2 C-FeCu catalyst was designed by thermal reduction and carburization of precursor. • ·cinnamaldehyde/benzalacetone were synthesized at high yields and selectivities. • · α , β -unsaturated aldehyde/ketone were electrosynthesized in gentle and green manner. • ·C C coulping reaction was fulfilled by combined electrochemical-chemical pathway. Oxygen evolution reaction (OER) is the efficiency limiting half-reaction in water electrolysis for green hydrogen production due to the 4-electron multistep process with sluggish kinetics. The electrooxidation of thermodynamically more favorable organics accompanied by C C coupling is a promising way to synthesize value-added chemicals instead of OER. Efficient catalyst is of paramount importance to fulfill such a goal. Herein, a molybdenum iron carbide-copper hybrid (Mo 2 C-FeCu) was designed as anodic catalyst, which demonstrated decent OER catalytic capability with low overpotential of 238 mV at response current density of 10 mA cm−2 and fine stability. More importantly, the Mo 2 C-FeCu enabled electrooxidation assisted aldol condensation of phenylcarbinol with α -H containing alcohol/ketone in weak alkali electrolyte to selective synthesize cinnamaldehyde/benzalacetone at reduced potential. The hydroxyl and superoxide intermediate radicals generated at high potential are deemed to be responsible for the electrooxidation of phenylcarbinol and aldol condensation reactions to afford cinnamaldehyde/benzalacetone. The current work showcases an electrochemical-chemical combined C C coupling reaction to prepare organic chemicals, we believe more widespread organics can be synthesized by tailored electrochemical reactions. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: An efficient electrochemical approach has been developed for the construction of 3‐sulfanylquinoline derivatives by treating phenylethynylbenzoxazinanones with disulfides in an undivided cell. The protocol provided a convenient route to functionalized quinolines with good functional group tolerance. Moreover, it does not require any metal catalysts or additives, furnishing a series of biological quinolines in moderate to good yields. [ABSTRACT FROM AUTHOR]

The electrocatalytic selective oxidation of 5‐hydroxymethylfurfural (HMF) presents a highly efficient and eco‐friendly method for biomass utilization. Herein, we synthesized pure β‐Ni(OH)2 and amorphous Ni(OH)2 on nickel foam (NF) using a facile stepwise electrodeposition technique and evaluated their catalytic performances for the oxidation of HMF to 2,5‐furan dicarboxylic acid (FDCA). The β‐Ni(OH)2 nanosheets‐decorated electrode (β‐NiNS/NF) exhibited excellent interfacial lattice matching with the substrate nickel, resulting in enhanced electron transfer at the catalyst‐substrate interface, as confirmed by electrochemical analysis. Consequently, the β‐NiNS/NF electrode displayed improved intrinsic electrocatalytic activity and interfacial stability. Additionally, it demonstrated effective HMF adsorption capability. These advantageous properties led to enhanced HMF conversion, selectivity, and structural stability. Notably, the β‐NiNS/NF electrode achieved an unprecedented FDCA yield of 80.6 % under relatively large current density galvanostatic electrolysis commonly used in industry. Moreover, our investigation identified a novel possible oxidation pathway during HMF electrocatalysis. This study not only showcases an efficient and scalable synthetic approach but also highlights the potential of the β‐NiNS/NF electrode for industrial HMF electrocatalytic oxidation under conditions involving relatively large applied currents. [ABSTRACT FROM AUTHOR]

Re-evaluation of conventional wastewater treatment processes is of paramount importance to improve the overall quality of our aquatic environment. Electrochemical Advanced Oxidation Processes (EAOPs) are the most promising alternative methods with application in wastewater treatment facilities since in situ electrogenerated oxidant agents degrade and mineralize a wide range of water pollutants. Boron-doped diamond (BDD) technology has proven its excellency in the anodic oxidation (AO) of different pollutants. In this work, we describe the use of a systematic literature review (SLR) methodology and a bibliometric analysis tool for the assessment of a representative sample of work (hundreds of publications) concerning the synergism between AO using BDD technology and other oxidation methods. One section of the discussion relates to different techniques used to enhance the AO performance of BDD technology, namely persulfate radicals or ozone and photoelectrocatalysis, whereas the second one considers Fenton-based reactions. A standard synergism effect occurs between AO using BDD technology and the add-ons or the Fenton-based methods, resulting in the enhancement of the degradation and mineralization efficiencies. The future of EAOPs using BDD technology must include renewable energy sources to self-sustain the overall process, and further research on the subject is mandatory to enable the effective acceptance and application of such processes in wastewater remediation facilities. [ABSTRACT FROM AUTHOR]

Electrocatalytic oxidation of ammonia is an appealing, low‐temperature process for the sustainable production of nitrites and nitrates that avoids the formation of pernicious N2O and can be fully powered by renewable electricity. Currently, however, the number of known efficient catalysts for such a reaction is limited. The present work demonstrates that copper‐based electrodes exhibit high electrocatalytic activity and selectivity for the NH3 oxidation to NO2− and NO3− in alkaline solutions. Systematic investigation of the effects of pH and potential on the kinetics of the reaction using voltammetric analysis andin situ Raman spectroscopy suggest that ammonia electrooxidation on copper occurrs via two primary catalytic mechanisms. In the first pathway, NH3 is converted to NO2− via a homogeneous electrocatalytic process mediated by redox transformations of aqueous [Cu(OH)4]−/2− species, which dissolve from the electrode. The second pathway is the heterogeneous catalytic oxidation of NH3 on the electrode surface favoring the formation of NO3−. By virtue of its nature, the homogeneous‐mediated pathway enables higher selectivity and was less affected by electrode poisoning with the strongly adsorbed "N" intermediates that have plagued the electrocatalytic ammonia oxidation field. Thus, the selectivity of the Cu‐catalyzed NH3 oxidation towards either nitrite or nitrate can be achieved through balancing the kinetics of the two mechanisms by adjusting the pH of the electrolyte medium and potential. [ABSTRACT FROM AUTHOR]

2,4,6-trichlorophenol (TCP) is a persistent pollutant introduced in water by industrial processes and pesticides. We have studied the electrooxidation of TCP on glassy carbon (GC) electrodes drop-coated with a suspension containing Mo- and/or Co-modified zeolite, graphite, and Nafion® perfluorinated ion-exchange resin in distilled water. Three zeolites, Linde type A (ZA), Faujasite (ZY) and MFI (ZSM-5), of different hydrophilic/hydrophobic character, were modified with molybdenum and/or cobalt by the wet impregnation method and characterized by Fourier-transform infrared spectroscopy with attenuated total reflection and temperature programmed reduction. The electrochemical study included cyclic voltammetry, electrochemical impedance spectroscopy, and electrolysis at controlled potential. High performance liquid chromatography and mass spectrometry allowed detecting the following reaction products: 2,6-dichloro-1,4-benzoquinone, 2,6-dichloro-1,4-hydroquinone, 3,5-dichloro-2-hydroxy-1,4-benzoquinone, and malic, maleic, picric, and acetic acids. A maximum degradation of about 90% was reached after 4 h of electrolysis at 0.83 V vs Ag/AgCl/KCl 3 M, using a GC/graphite-ZSM5Mo electrode. The electrodes modified with Mo, and especially that with ZSM5, the most hydrophobic zeolite, were active for the degradation of TCP. We conclude that the main role of the Mo species is to catalyze the hydrogen peroxide decomposition yielding reactive singlet oxygen, as evidenced by the pink color of 3,5-dichloro-2-hydroxy-1,4-benzoquinoneand confirmed by mass spectrometry. [ABSTRACT FROM AUTHOR]

Lignin valorization is essential for biorefineries to produce fuels and chemicals for a sustainable future. Today's biorefineries pursue profitable value propositions for cellulose and hemicellulose; however, lignin is typically used mainly for its thermal energy value. To enhance the profit potential for biorefineries, lignin valorization would be a necessary practice. Lignin valorization is greatly advantaged when biomass carbon is retained in the fuel and chemical products and when energy quality is enhanced by electrochemical upgrading. Though lignin upgrading and valorization are very desirable in principle, many barriers involved in lignin pretreatment, extraction, and depolymerization must be overcome to unlock its full potential. This Review addresses the electrochemical transformation of various lignins with the aim of gaining a better understanding of many of the barriers that currently exist in such technologies. These studies give insight into electrochemical lignin depolymerization and upgrading to value‐added commodities with the end goal of achieving a global low‐carbon circular economy. [ABSTRACT FROM AUTHOR]

Various organic functions can undergo oxidation reactions, and the chemical industry increasingly seeks to develop processes based on the Green Chemistry approach in the search for more sustainable practices. Electrochemical electron transfer processes using metal complexes thus appear as an important alternative in these oxidative processes since they exploit numerous reactions in aqueous media and use catalytic amounts of the complex. The purpose of this work was to test the electrocatalytic ability of a new ruthenium (II) diarsenic aqua complex, [Ru(L)(totpy)(OH2)](ClO4)2 (L=Ph2AsCH2CH2AsPh2); (totpy=4'-(4-tolyl)-2,2':6',2"-terpyridine), in electrooxidation experiments of organic substances with different functions. The experiments were conducted at a constant potential of +1.00 V (vs ECS) in a solution of 7:3 phosphate buffer: t-butanol, pH 8.1, with a ratio of 1.00 mmol.L-1 of the aqua complex [Ru(L)(totpy)(OH2)](ClO4)2 to 50.00 mmol.L-1 of each organic substrate. The oxidized organic starting materials and the respective products obtained therefrom were benzyl alcohol (benzaldehyde), benzaldehyde (benzoic acid), benzyl butyl ether (benzaldehyde and benzoic acid) and 1-phenylethanol (acetophenone). Selective reactions with good yields for the products were observed. The electrochemical process used here revealed some benefits over other classic oxidative methods, such as biological advantages and inorganic oxidants, emphasizing the speed, the possibility of using aqueous media in the reactions, selectivity in the formation of products, and the possibility of using small amounts of catalyst. [ABSTRACT FROM AUTHOR]

A single‐molecule method has been developed based on the scanning tunneling microscope (STM) to selectively couple a series of aniline derivatives and create azobenzenes. The Au‐catalyzed oxidative coupling is driven by the local electrochemical potential at the nanostructured Au STM tip. The products are detected in situ by measuring the conductance and molecular junction elongation and compared with analogous measurements of the expected azobenzene derivatives prepared ex situ. This single‐molecule approach is robust, and it can quickly and reproducibly create reactions for a variety of anilines. We further demonstrate the selective synthesis of geometric isomers and the assembly of complex molecular architectures by sequential coupling of complementary anilines, demonstrating unprecedented control over bond formation at the nanoscale. [ABSTRACT FROM AUTHOR]

• DFT is used to examine the electrooxidation mechanism of furfural on Pt(1 1 1). • Furoic acid is a stable oxidation product that is difficult to decarboxylate. • Paths to further oxidation products including maleic acid are detailed. • Experimental results presented show product distribution at 0.9 V-RHE. Electro-oxidation of furfural may allow for tunability of product selectivity by varying the electrode potential. We have applied density functional theory (DFT) to investigate the electrocatalytic oxidation mechanism on the Pt (1 1 1) surface. The potential-dependent reaction free energy profiles for furfural electrocatalytic oxidation to furoic acid, succinic acid, maleic acid, and maleic anhydride are reported. After comparing several possible furfural oxidation paths, we conclude that the electro-oxidation of furfural preferentially proceeds to furoic acid, with further oxidation slowed by difficult C C bond dissociation. Oxidation beyond furoic acid can proceed to succinic acid via 2 (3H)-furanone as an intermediate and to maleic acid and maleic anhydride via 2 (5H)-furanone as an intermediate. The rate of these processes is likely limited by the decarboxylation of furoic acid. DFT analysis of elementary step thermodynamics and kinetics suggests that the selectivity between furoic acid, succinic acid, maleic acid, or other oxidized products is tunable by varying the electrode potential. Initial experimental results show furoic acid as the most significant product (>80% selectivity) at 0.9 V-RHE on a Pt electrode, in agreement with DFT results. These results broaden our fundamental understanding into electrocatalytic oxidation of furfural, which is applicable in upgrading renewable biomass derivatives. [ABSTRACT FROM AUTHOR]

In this work, we prepared reduced graphene oxide-supported PtCo nanospheres (PtCo/rGO) by a facile one-step hydrothermal method with the assistance of L-proline as the shape-directing agent. We systematically investigated the effects of various experimental conditions on the morphology and structure of the as-prepared PtCo/rGO hybrids. Compared with commercial Pt/C (10 wt%) and Pt/rGO catalysts, the as-prepared PtCo/rGO has better catalytic activity and poisoning resistance toward methanol electrooxidation and can be used as a promising catalyst for direct methanol fuel cells.Graphical abstract: The rGO-supported PtCo nanosphere hybrids are successfully synthesized by a facile one-pot hydrothermal method with the assistance of L-proline. L-proline acts as shape-controlled agent for synthesizing PtCo/rGO. The as-prepared PtCo/rGO hybrids exhibit a higher electrocatalytic activity and poisoning-resistant ability for methanol oxidation in acidic media. [ABSTRACT FROM AUTHOR]

Highlights • A highly sensitive and selective electrochemical sensor for determination of morin. • Electrodeposition of Ir nanograins on PEDOT modified CFP electrode. • High electrocatalytic activity of Ir-PEDOT/CFP towards morin oxidation. • Successful detection of picomolar levels of morin in mulberry leaves. Abstract Nanoclusters of Ir were electrochemically deposited on carbon fiber paper (CFP) substrate modified with poly(3,4-ethylenedioxythiophene) (PEDOT), a conducting polymer between the potential range 0.0 V and 0.6 V at 0.05 V/s scan rate. The electrocatalytic activity of Ir–PEDOT/CFP electrode towards oxidation of morin, a flavonoid was significantly greater than that of PEDOT/CFP and bare CFP electrodes. Factors affecting the anodic peak of morin namely, effect of pH, scan rate and number of cycles were optimized. The electrochemical route involved adsorption controlled and irreversible processes. Under optimal conditions, the linear dynamic range for the determination of morin was found to be 0.12 nM–2.80 nM. The significantly low detection limit (42.18 pM) demonstrates the ultrasensitivity of the proposed method. The reliability of the method was evaluated for the quantification of morin present in mulberry leaves, guava leaves and grape wine. [ABSTRACT FROM AUTHOR]

Abstract Shape-controlled synthesis of well-defined nanostructures offers a great opportunity to promote electrocatalytic performances while reducing the mass loading of noble metals. Herein, we show how morphology can effectively affect the electrocatalytic properties of nanocrystals for alcohol electrooxidation reaction, a key barrier to the application of fuel cells. We report the synthesis of a new generation of alloyed PtSn concave nanocubes (CNCs) through a facile one-pot wet-chemical method. Owing to strong synergistic effect between Pt and Sn, modified electronic structure, as well as high surface areas, the as-obtained alloyed PtSn CNCs can display outstanding electrocatalytic performances for liquid fuel electrooxidation. Impressively, the optimized Pt 4 Sn 1 concave nanocubes (CNCs) can achieve a factor of 5.1 enhancements in mass activity and a factor of 5.9 enhancements in specific activity towards ethylene glycol oxidation (EGOR) in comparison with commercial Pt/C catalysts. Moreover, 4.6 and 5.3-fold enhancements in mass and specific activity were also acquired for glycerol oxidation reaction (GOR) compared to those of the commercial Pt/C, holding great promise for future application in fuel cells. Graphical abstract Image 1 Highlights • A unique class of concave PtSn nanocubes has been designed. • Such concave PtSn nanocubes can expose more surface active areas. • The synergistic effect contributes to the enhancement of catalytic performances. • Such concave PtSn nanocubes show high performance for EGOR and GOR. [ABSTRACT FROM AUTHOR]

Ni–metal oxide (Fe 2 O 3 , ZnO, Co 3 O 4 and MnO 2 ) nanocomposites were synthesized on carbon substrates by electrodeposition technique. These catalysts were tested as anodes for electrooxidation of both methanol and ethanol. To study the chemical composition of the deposits, energy dispersive X-ray spectroscopy (EDX) was used and the maximum wt% of metal oxides in the prepared composites was found to be 11.4, 11.7, 9.3 and 3.8 for Fe 2 O 3 , ZnO, MnO 2 and Co 3 O 4 , respectively. The morphology of the catalysts surface is significantly affected by the existence of metal oxides as confirmed by scanning electron microscope (SEM) images. The phase structure and the particle size of the catalysts were recognized from X-ray diffraction (XRD). A reduction in the Ni grains was seen in the matrix of the composites compared with that of Ni/C. Cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) were employed to study the electrocatalytic activity of the prepared nanocomposites. All the results displayed a satisfactory electrocatalytic activity, better stability, lower charge transfer resistance, and stronger resistance to the poisoning of the nanocomposites compared with that of Ni/C. A synergistic effect among multiple active sites due to the presence of mixed oxides for the nanocomposites could enhance their electrocatalytic activity. The performance of the different prepared catalysts towards the electrooxidation process was established in the order of: Ni–Fe 2 O 3 /C > Ni–ZnO/C > Ni–Co 3 O 4 /C > Ni–MnO 2 /C > Ni/C. Ni–metal oxide nanocomposites appeared to be promising and less expensive anode catalysts for fuel cell applications. [ABSTRACT FROM AUTHOR]

Abstract: Rhodium(III) catalysis has enabled a plethora of oxidative C−H functionalizations, which predominantly employ stoichiometric amounts of toxic and/or expensive metal oxidants. In contrast, we herein describe the first electrochemical rhodium‐catalyzed C−H activation that avoids hazardous chemical oxidants. Environmentally benign twofold C−H/C−H functionalizations were accomplished with weakly coordinating benzoic acids and benzamides, employing electricity as the terminal oxidant and generating H2 as the sole byproduct. [ABSTRACT FROM AUTHOR]

This paper reported our extensive efforts in the design of concave PdRu nanocubes via a facile wet-chemical strategy. Different from the previously reported PdRu nanostructures, the as-prepared concave PdRu nanocubes combined the advantages of fascinating nanocube structure, synergistic and electronic effect as well as high surface area. All of these beneficial terms endow them to exhibit superior electrocatalytic activity and long-term stability towards ethylene glycol oxidation as compared with commercial Pd/C. Our work highlights the significance of shape-controlled of PdRu nanostructures over the electrocatalytic performances towards the electrooxidation of ethylene glycol (EG), which will pave up a new strategy for boosting the development of renewable and clean energy technology. [ABSTRACT FROM AUTHOR]

The design of cost-efficient catalysts for the electrooxidation of liquid fuel is now highly desirable for the commercial application of direct fuel cells. In spired by this, we herein reported our tremendous efforts in the fabrication of core-shell PdAu convex nanospheres via a green method. Different from the previously reported PdAu core-shell nanostructures, the present PdAu convex nanospheres integrated the benefits of core/shell, many granular protuberances, alloy and electronic effect as well as high surface area. All of these favorable properties embody them to exhibit greatly enhanced electrocatalytic activity and long-term stability towards ethylene glycol oxidation as compared with commercial Pd/C. This work emphasizes the significance of shape-controlled of PdAu nanostructures over the electrocatalytic performances for the ethylene glycol oxidation. [ABSTRACT FROM AUTHOR]

Ir nanoparticles have been synthesized by using a sample hydrothermal method while well dispersed Ir@SiO 2 composite microspheres could be obtained hydrothermally after adding SiO 2 microspheres into the synthesis system. Particles of Ir formed on the surface of SiO 2 microspheres were well crystalline similar to the pure Ir nanoparticles. Both the glassy carbon electrodes modified by Ir nanoparticles and Ir@SiO 2 composite microspheres showed weak electrochemical activities toward oxidation of dopamine and ascorbic acid. However, the Ir nanoparticles modified gold electrode displayed an obvious catalytic activity toward electrooxidation of either dopamine or ascorbic acid. For the gold electrode modified with Ir@SiO 2 composite microspheres, the electrochemical behavior could be affected obviously by the quantity of the electrocatalyst on the surface of bare gold electrode. The relationship between structure and property of both samples have been studied and analyzed based on the experimental data. [ABSTRACT FROM AUTHOR]

In this study, we have successfully synthesized the M@Pt (M = FeO, Co and Ni) nanoparticles catalysts through the sodium borohydride reduction method for a comparative studies of their electrocatalytic performance towards ethanol oxidation in acidic media. After the structure, surface morphology and chemical composition characterization of the synthesized core-shell nanoparticles, their electrocatalytic activities towards oxidation of ethanol in acidic media were studied in detail. We investigated the effect of the core element (FeO, Co and Ni) on the electrochemical behaviour as well as the enhancement of the electrocatalytic activity for ethanol oxidation reaction. Overall, the obtained results show that the all of these electrocatalysts exhibited an enhanced activity than Pt-alone nanoparticles towards ethanol oxidation reaction. On the other hand, the comparative studies of their electrocatalytic performance show that the Ni@Pt nanoparticles present the best performance with the maximum electrocatalytic activity and stability. [ABSTRACT FROM AUTHOR]

A nanocomposite containing Au, polyaniline (PANI) and reduced graphene oxide (RGO) has been synthesized by a two-step method. The PANI can intermix with graphene to build a three-dimensional (3D) structure, which is beneficial for uniform dispersion of Au networks with a mean diameter of 5.6 nm. In addition to its role as the support of Au, the presence of PANI is also favorable for avoiding the heavy agglomeration of graphene when the reduction occurs. Additionally, the introduction of graphene can not only boost the connections with PANI, but also accelerate the electron transfer between the electrolyte solution and catalysts. Electrochemical tests indicate that the Au/PANI/RGO hybrid exhibits high catalytic activity and stability for ethanol electrooxidation in alkaline conditions. The superior performance can be ascribed to the uniform dispersion of the Au nanocatalyst on the PANI/RGO support with a particular 3D structure, resulting in an increase of the electrochemically active surface area together with a synergic effect between the PANI, graphene and Au. [ABSTRACT FROM AUTHOR]

In the current study, well-defined PdCo porous nanostructure (PdCo PNS) is prepared by a simple one-pot wet-chemical method and polypyrrole@multi-walled carbon nanotubes (PPy@MWCNTs) nanocomposite is used as a catalyst support. The morphology and the structural properties of the prepared catalyst were studied by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The electrocatalytic performance of PdCo PNS/PPy@MWCNTs on glassy carbon electrode has been evaluated by cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) techniques. The specific activity of PdCo PNS/PPy@MWCNTs for ethanol electrooxidation (1.65 mA cm −2 ) is higher than those of other compared electrocatalysts. Also, PdCo PNS/PPy@MWCNTs catalyst represented higher electrocatalytic activity, better long-term stability and high level of poisoning tolerance to the carbonaceous oxidative intermediates for ethanol electrooxidation reaction in alkaline media. Furthermore, the presence of PPY@MWCNTs on the surface of GCE produce a high activity to electrocatalyst, which might be due to the easier charge transfer at polymer/carbon nanotubes interfaces, higher electrochemically accessible surface areas and electronic conductivity. The superior catalytic activity of PdCo PNS/PPy@MWCNTs suggests it to be as a promising electrocatalyst for future direct ethanol fuel cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • BDD, Ti/PbO 2 , and Ti/Pt electrodes were compared for EOx system. • The PCT degradation efficiency for US, EOx and EOx-US were obtained as < 1%, 70.5 % and 92.4 %. • Effect of US frequency (100–600 kHz) and power (25–100 W) were investigated. • Best conditions were obtained with 200 kHz, 75 W with BDD electrode. In this work, paracetamol (PCT) containing synthetic wastewater was investigated by electrooxidation (EOx) and ultrasound (US) hybrid process. Firstly, anode type (BDD, Ti/PbO 2 , and Ti/Pt) and process types including ultrasound (US), electro-oxidation (EOx) and hybrid process (EOx-US) were investigated for the degradation of paracetamol (PCT). The PCT degradation efficiency for US, EOx and EOx-US using BDD anode were obtained as < 1%, 70.5 % and 92.4 %, respectively. US-EOx process was found the most effective process in PCT and TOC degradation by using BDD electrodes because of the synergistic effect between sonolysis and electrocatalysis. Then, the effects of operation parameters such as US frequency (100–600 kHz) and US power (25–100 W), conductivity (3500–5500 μS cm−1), current density (50–500 A m−2), initial PCT concentration (20–500 ppm) and pH (2–8) on the PCT degradation with time dependency by EOx-US hybrid process were investigated. The optimum conditions were found as 200 kHz, 75 W, pH 2, 4500 μS cm−1, 100 A m−2, and 100 ppm when the PCT and TOC degradation efficiencies and the operating circumstances were considered. Additionally, the toxicity of the treated wastewater was examined, and it was discovered that the byproducts' formation caused the inhibition ratio to rise, making the solution more toxic than the initial solution. Frequency effect has not been studied much in hybrid processes in the literature, and it makes this study in this sense valuable. [ABSTRACT FROM AUTHOR]

Improving the electrocatalytic activity, durability, and utilization of anode eletrocatalysts are crucial for accelerating commercialization of direct formic acid fuel cells. In this work, the multiwall carbon nanotubes (MWCNTs) supported PtAu alloy nanocrystals (MWCNTs/PtAu) composites are synthesized by a one-pot wet-chemical method using polyethyleneimine as the complexant and surfactant. The physicochemical properties of the as-prepared MWCNTs/PtAu composites are characterized detailedly by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy, etc . These structural investigations display the PtAu alloy nanocrystals are highly dispersed on the surface of the MWCNTs. Cyclic voltammetry and chronoamperometry measurements show the as-prepared MWCNTs/PtAu composites significantly enhance the direct dehydrogenation pathway of the formic acid oxidation reaction, resulting in the improved electocatalytic activity and durability for the formic acid electrooxidation. [ABSTRACT FROM AUTHOR]

2,2,6,6-Tetramethyl-1-piperidine N -oxyl (TEMPO) and nickel hydroxide (Ni(OH) 2 ) mediated electrooxidation of glycine were performed and roles of bases in these two reactions were investigated by cyclic voltammetry. Trends of 2,4,6-collidine > 2,6-lutidine > 3-picoline > pyridine and KOH > NaOH > LiOH were observed in the studies of bases dependent activities on TEMPO and Ni(OH) 2 mediated glycine electrooxidation, respectively. Base effects can be rationalized by acid neutralization, base assisted deprotonation and the interaction between bases and catalysts. [ABSTRACT FROM AUTHOR]

Three alternative methods were developed for the synthesis of modifying palladium-polypyrrole layers on the surface of an inert electrode. Their electrocatalytic activity toward formaldehyde under inert atmosphere was checked. All the suggested methods are one-stage and allow synthesis of a film on the electrode surface from a solution containing a palladium salt and pyrrole in the absence of other active reagents. The electrochemical methods (potentiodynamic and double cathodic and anodic pulses techniques) in an aqueous medium give films with poorly reproducible electrocatalytic properties, while the chemical redox synthesis affords films with reproducibly high electroactivity toward methylene glycolate. [ABSTRACT FROM AUTHOR]

Self-supporting porous silver foils with an average pore size < 100 nm were produced from a crystalline silver-based ternary alloy as a precursor by removing second phases present in the silver matrix. The final Ag-based porous foil shows good mechanical properties when comparing to its previous amorphous analogues. Its activity for direct electrochemical oxidation of ammonia-borane (AB), a fuel of interest for direct liquid fuel cells, has been investigated in alkaline media. The material exhibits promising electrochemical properties in long-term operation; indeed, material composition and nanostructure remain similar after 15,000 cyclic-voltammetries between − 0.3 and 0.5 V vs. RHE in a 0.1 M NaOH + 5 mM AB solution thermostated at 25 °C. Nanoporous materials, and in particular nanoporous silver, can therefore represent a relevant choice as anode in direct ammonia-borane fuel cell. [ABSTRACT FROM AUTHOR]

The palladium species were deposited on the multi-walled carbon nanotubes dispersed in nafion membrane by pulsed electrodeposition technique. The resulting modified electrode was defined CNT-Pd. The Pd electrodeposition was carried out in 50 mM H 2 SO 4 solution containing 4.0 mM Pd(NO 3 ) 2 using a double pulse sequence of potentials: E 1 = −0.4 V vs SCE (t 1 = 0.03 s) and E 2 = 0.4 V vs SCE (t 2 = 3 s). SEM analysis showed a well-efficient distribution of Pd nanoparticles dispersed along the nanotubes randomly oriented in the nafion matrix. A surface loading of electrodeposited Pd species comprised between 2.0 nmol and 2.5 nmol was generally observed. The prepared electrode is useful to catalyze the electrooxidation of hydrazine and propranolol. The electroanalytical properties of the electrode were evaluated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under optimized DPV conditions, the CNT-Pd electrode exhibits interesting analytical performance in terms of linear range of concentrations, low detection limits (i.e., 8 μM and 2 μM for hydrazine and propranolol, respectively) and good temporal stability of the responses (i.e., 4%–5%). [ABSTRACT FROM AUTHOR]

Herein, the role of modified electrode comprised of polypyrrole (PPy), graphene oxide (GO), multi walled carbon nanotubes (MWCNTs) and copper (I) oxide nanoparticles in the electrochemical methanol oxidation is considered. The modified electrodes prepared through the successive Layer by Layer (LBL) electrochemical and sonoelectrochemical deposition processes. As-fabricated electrodes were characterized by FT-IR spectroscopy and scanning electron microscopy (SEM), which confirmed the incorporation of GO into the PPy matrix. Afterward, the electrocatalytic performance of as-prepared electrodes was evaluated for methanol oxidation reaction by cyclic voltammetry (CV), chronoamperometry, and electrochemical impedance spectroscopy (EIS). It was found that the Pd sub-layer has a vital role in synthesis of Cu 2 O nanostrucures, because this noble nano-layer can protect the copper substrate and consequently lead to synthesis of Cu 2 O nanostrucures. CV measurements indicated that the simultaneous presence of GO with PPy and MWCNTs in the structure of electrode enhances the overall electrocatalytic performance of the LBL electrodes for methanol oxidation. So, a strong synergistic interaction is expected to be between these components. Moreover, the results from chronoamperometry confirmed that the modified electrode had a good stability and repeatability as electrocatalyst. [ABSTRACT FROM AUTHOR]

In this paper, polypyrrole@multi-walled carbon nanotubes (PPy@MWCNTs) nanocomposite as a catalyst support material is fabricated. Pd nanoflowers (NFs) were deposited on a PPy@MWCNTs modified glassy carbon electrode (GCE) by a facile electrochemical approach. The morphology and composition of the Pd NFs/PPy@MWCNTs are characterized by SEM (scanning electron microscopy) and EDS (energy dispersive spectroscopy), respectively. The catalytic performance of Pd NFs/PPY@MWCNTs catalyst is examined by cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy toward methanol oxidation reaction (MOR) in alkaline media. The mass activity of Pd NFs/PPY@MWCNTs (725 mA mg −1 ) is 8.09 times higher than that of the Pd NFs catalyst (89.6 mA mg −1 ). Meanwhile, the ratio of forward current (j f ) to reverse current (j b ) for the polymer supported catalyst is almost 2.6 times higher than that of the Pd NFs. Furthermore, PPY@MWCNTs produces a high activity to electrocatalyst, which might be due to higher electrochemically surface area and electronic conductivity. This strategy provides a promising platform for direct methanol fuel cells. [ABSTRACT FROM AUTHOR]

In this study, an electrochemical sensor for hydrazine oxidation was synthesized using graphene functionalized by benzylamine molecules (both para and meta) and subsequently palladium (denoted as rGO-P x DA-Pd and rGO-M x DA-Pd, respectively). The synthesized materials were characterized using X-ray photon spectroscopy (XPS) and transmission electron microscopy (TEM). The TEM study suggested that the PdNPs was well dispersed on the surface of the rGO-P x DA-Pd rather than on the rGO-M x DA-Pd. The XPS confirm the benzylamine functionalization and Pd attachment. These materials were investigated using several electrochemical techniques including cyclic voltammetry, differential pulse voltammetry and chronoamperometry in 0.05 M phosphate buffer solution at pH 7.4. From these results, it is confirm that the rGO-P x DA-Pd is better catalyst than rGO-M x DA-Pd due to resonance, steric and aggregation effects. The superior hydrazine sensor, rGO-P x DA-Pd, appeared to exhibit a good linear range of 1 × 10 −6 M–7.4 × 10 −3 M and a detection limit of ( S/N = 3) 1.7 × 10 −7 M with a fast response time of 3 s. The selectivity of the rGO-P x DA-Pd for hydrazine was studied for a number of ions such as, Na + , Cl − , Ca +2 , Mg +2 , and SO 4 −2 and biomolecules such as glucose and ascorbic acid. [ABSTRACT FROM AUTHOR]

In this study, copper/nickel (CuNi) particle decorated multiwalled carbon nanotubes (MWCNTs) have been fabricated for nonenzymatic glucose detection by the electrodeposition of CuNi particles on a glassy carbon electrode (GCE) modified with Nafion-functionalized MWCNTs (fMWCNTs). Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses reveal that CuNi particles were successfully deposited on the fMWCNTs/GCE. The as-synthesized CuNi/fMWCNT composite reveals the shape characteristics of dendrite with a Cu/Ni atomic ratio of around 88.1/11.9. The nonenzymatic glucose sensor based on CuNi/fMWCNT composite shows excellent electrocatalytic activity toward glucose oxidation with a high sensitivity (1470.2 μA cm mM), a low detection limit (2.5 nM, signal/noise (S/N) ratio = 3), and a wide linear range (0.1-5000 μM). Moreover, the sensor has been successfully used for the assay of glucose in human serum samples with good recovery, ranging from 95.6 to 100.1 %. These results indicate that CuNi/fMWCNT composite is an ideal candidate for novel nonenzymatic glucose sensor because of its high sensitivity, good selectivity, good stability, and low cost. [ABSTRACT FROM AUTHOR]

The shape-controlled synthesis of multicomponent metal nanocrystals (NCs) bounded by high-index facets (HIFs) is of significant importance in the design and synthesis of highactivity catalysts. We report herein the preparation of Pt-Ni alloy NCs by tuning their shape from concave-nanocubic (CNC) to nanocubic and hexoctahedral (HOH). Owing to the synergy of the HIFs and the electronic effect of the Pt-Ni alloy, the as-prepared CNC and HOH Pt-Ni alloy NCs exhibited excellent catalytic properties for the electrooxidation of methanol and formic acid, as well as for the oxygen reduction reaction (ORR). [ABSTRACT FROM AUTHOR]

A facile method for the rapid synthesis of dendritic PdAu alloyed bimetallic nanocrystals is demonstrated. The whole synthetic process is very simple just by mixing Na 2 PdCl 4 , HAuCl 4 , polyvinylpyrrolidone and hydroquinone and heated at 50 °C for 15 min. The as-prepared dendritic PdAu nanoparticles exhibit superior catalytic activity for methanol, ethanol and glycerol electrooxidation in alkaline solution, and their catalytic performance is composition-dependent. [ABSTRACT FROM AUTHOR]

GO/CuO nanocomposite had been successfully synthesized by electrostatic interactions method. X-ray powder diffraction(XRD), Scanning electron microscopy(SEM), transmission electron microscope(TEM), selective-area electron diffraction(SAED), Fourier transform infrared spectroscopy(FT-IR), and Raman spectra confirmed the structure of the CuO and GO/CuO nanocomposite. The property of GO/CuO nanocomposite for electrocatalytic oxidation of glucose was investigated by cyclic voltammetry. The experimental results indicate that the GO/CuO nanocomposite modified electrode allows highly sensitive and low working potential of glucose and is promising for the future development of non-enzymatic glucose sensors. [ABSTRACT FROM PUBLISHER]

The palladium nanoparticle grafted manganese oxyhydroxide nanorod (MON) electrocatalyst has been synthesized and tested for the electrooxidation of ethylene glycol (EG) in an alkaline medium. The MON was prepared using the hydrothermal method and the Pd nanoparticles were coated on the MON using an in situ reduction method. The nanocatalyst thus prepared was characterized by powder X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, energy dispersive X-ray spectroscopy and electrochemical methods. The microscopic studies confirm the formation of MON and reveal that the Pd nanoparticles were grafted uniformly on the MON. In the voltammetric studies, the Pd/MON catalyst exhibited a six-fold improved peak current for ethylene glycol electrooxidation compared with the C/Pd. The EG electrooxidation reaction performances of the Pd/MON nanocatalyst in the alkaline solutions containing different quantities of EG were tested through cyclic voltammetry. The catalytic removal of the poisonous intermediates formed during electrooxidation of EG was explained. The present study shows that MON can act as an active support for the Pd nanocatalyst. [ABSTRACT FROM AUTHOR]

Electroless Ni-P and Ni-P-TiCN composite coatings have been deposited successfully on Al substrates. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques were applied to study the surface morphology and the chemical composition of the deposited films. Moreover, X-ray diffraction (XRD) proved that Ni-P and Ni-P-TiCN deposits have amorphous structures. The properties of Ni-P-TiCN/Al composite films such as hardness, corrosion resistance and electrocatalytic activity were examined and compared with that of Ni-P/Al film. The results of hardness measurements reveal that the presence of TiCN particles with Ni-P matrix improves its hardness. Additionally, the performance against corrosion was examined using Tafel lines and electrochemical impedance spectroscopy techniques in both of 0.6 M NaCl and a mixture of 0.5 M H2SO4 with 2 ppm HF solutions. The results indicate that the incorporation of high dispersed TiCN particles into Ni-P matrix led to a positive shift of the corrosion potential and an increase in the corrosion resistance for all aluminum substrates after their coating with Ni-P-TiCN. In addition, Ni-P-TiCN/Al electrodes showed a higher electrochemical catalytic activity and stability toward methanol oxidation in 0.5 M NaOH solution compared with that of Ni-P/Al. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: Kinetics and mechanism of formic acid (FA) oxidation on platinum and upd-lead ad-atoms modified platinum electrodes have been studied using unlabelled and deuterated compounds. Poisoning of the electrode surface by CO-like species was prevented by suppression of dissociative chemisorption of FA due to a fast competitive underpotential deposition of lead ad-atoms on the Pt surface from an acidic solution containing Pb2+ cations. Modification of the Pt electrode with upd lead induced a catalytic effect in the direct electrooxidation of physisorbed FA to CO2. With increasing degree of H/D substitution, the rate of this reaction decreased in the order: HCOOH > DCOOH ≥ HCOOD > DCOOD. HCOOH was oxidized 8.5-times faster on a Pt/Pb electrode than DCOOD. This primary kinetic isotope effect proves that the C–H- and O–H-bonds are simultaneously cleaved in the rate determining step. A secondary kinetic isotope effect was found in the dissociative chemisorption of FA in the hydrogen adsorption–desorption range on a bare Pt electrode after H/D exchange in the C–H bond, wherein the influence of deuterium substitution in the O–H group was negligibly small. Thus the C–H bond cleavage is accompanied by the C–OH and not the O–H bond split in the FA decomposition, producing CO-like species on the Pt surface sites. [Copyright &y& Elsevier]

Abstract: In the present paper, the electrocatalytic abatement of urea in aqueous solutions has been studied by means of cyclic voltammetry and galvanostatic electrolysis, using different anodes such as Pt, Ti–Ru oxide, boron-doped diamond (BDD) and antimony-doped tin oxide. HPLC analysis, total organic carbon (TOC) and ionic chromatography have been used to evaluate the oxidation and the mineralization of the treated aqueous solutions. The results of the cyclic voltammetries have shown that, in the case of Pt and Ti–Ru oxides a decrease in current density in the oxygen evolution region can be observed in the presence of urea, due to the blockage of the electrode active oxygen evolution sites as a consequence of the reversible adsorption of urea. Instead, a notable increase in the current density has been observed in the region of the oxygen evolution for the BDD and antimony-doped tin oxide electrodes, in the presence of urea, indicating that the oxidation of urea involves hydroxyl radicals. The bulk electrolysis tests have shown that the complete removal of urea and TOC can only be achieved using a boron-doped diamond and that Pt, the Ti–Ru oxide and antimony-doped tin oxide only permit a partial oxidation of urea. On the basis of the TOC evolution and the identification of the organic intermediates and inorganic ions released during the treatment, a total mineralization has been proposed. Finally, electrolysis has been performed in the presence of chloride ions, which act as oxidation mediator, and a comparison has been done between direct and mediated electro-oxidation. [Copyright &y& Elsevier]

Abstract: A new method for the synthesis of the catalyst systems Pt–Mo was suggested. nPt0(H x−2n MoO3)/GC electrodes were prepared by a redox reaction between the hydrogen-containing molybdenum bronzes and potassium tetrachloroplatinate (II) in acid solutions at open circuit potential. The electrodes were characterized by CVA, SEM, X-ray microanalysis, XRD, XPS and ICP-AES. Pt0conglomerates formation with nonuniform distribution over the molybdenum bronzes surface has been revealed. nPt0(H x−2n MoO3)/GC electrodes showed high catalytic activity (not inferior to Pt–Ru-catalyst) in the oxidation of carbon monoxide and methanol as compared with Pt/GC-electrodes. Catalytic effect is apparently achieved by effective oxidation of strongly chemisorbed species (COads, HCOads), which occurs at boundaries platinum – molybdenum oxide. Therefore nPt0(H x−2n MoO3) can be considered as one of perspective catalysts for DMFC. [Copyright &y& Elsevier]

An electrochemical biosensor for the accurate determination of salicylic acid ( SA) is prepared by potentiostatic deposition of nickel on the glassy carbon electrode ( GCE). The electrochemical performance of the Ni/GCE film and the parameters affecting its activity are investigated by cyclic voltammetry, amperometry and electrochemical impedance spectroscopy ( EIS). The electrooxidation of SA is significantly enhanced on Ni/GCE, compared to GCE. Indeed, the modified electrode has a fast response (less than 3 s) and excellent linear behavior over a wide SA concentration range (2 μM-0.55 mM) with a detection limit ( LD) of 0.5 μM (signal/noise = 3) under the optimal conditions. Moreover, the stability and the reproducibility of the biosensor are satisfactorily evaluated. [ABSTRACT FROM AUTHOR]

Highlights: [•] Electrodeposition of Au nanoflowers supported on CFC for ethanol oxidation is reported. [•] Many thorn-like Au nanostructures have a common basis to form a single flower. [•] The as-prepared electrode exhibits good catalytic performance for ethanol electrooxidation. [Copyright &y& Elsevier]

Abstract: In the present work, we report a new and simple approach for preparing a highly ordered Au (111) nanoparticle (NP) array in SiO2 cavities on indium-doped tin oxide (ITO) electrodes. We fabricated a SiO2 cavity array on the surface of an ITO electrode using highly ordered self-assembly of polystyrene spheres as a template. Gold NPs were electrodeposited at the bottom of the SiO2 cavities, and single gold NPs dominated with (111) facets were generated in each cavity by annealing the electrode at a high temperature. Such (111) facets were the predominate trait of the single gold particle which exhibited considerable electrocatalytic activity toward oxidation of methanol, ethanol, and glycerol. This has been attributed to the formation of incipient hydrous oxides at unusually low potential on the specific (111) facet of the gold particles. Moreover, each cavity of the SiO2 possibly behaves as an independent electrochemical cell in which the methanol molecules are trapped; this produces an environment advantageous to catalyzing electrooxidation. The oxidation of methanol on the electrodes is a mixed control mechanism (both by diffusion and electrode kinetics). This strategy both provided an approach to study electrochemical reactions on a single particle in a microenvironment and may supply a way to construct alcohols sensors. [Copyright &y& Elsevier]

Abstract: A series of novel Pt–Pd/polyfluorenes (PFs) composite catalysts were facilely prepared based on Pt/Pd precursor and PFs with hydroxyl and carboxyl substitution at the C-9 position by electrochemical method and their electrocatalytic performance toward formic acid oxidation were studied. Electrocatalytic experiments demonstrate that the Pt–Pd nanoparticles immobilized on poly(9-fluorenecarboxylic acid) (PFCA)-decorated glassy carbon (GC) electrode (Pt–Pd/PFCA/GC) show larger electrochemical active surface area, higher catalytic activity and stability toward formic acid oxidation than that of other Pt–Pd/PFs/GC, Pt–Pd/GC, as well as the commercial JM 20% Pt/C/GC electrodes, which can be attributed to the small-sized and well-dispersed Pt–Pd nanoparticles on PFCA matrix and the special electronic interaction between the metal nanoparticles and the polymer substrate. Moreover, the electron-withdrawing carboxyl substitution rather than the electron-donating hydroxyl on the polymer main chain is of great benefit to the removal of poison CO as well as the enhancement of catalytic activity of Pt–Pd toward formic acid oxidation. [Copyright &y& Elsevier]

Abstract: Platinum nanoparticles have been successfully assembled on polyaniline functionalized graphite nanoplatelet (GNP) via a noncovalent functionalization strategy. The characterization of obtained nanocomposite was investigated by XRD, TEM, XPS and electrochemical technology. When the moderate amount of polyaniline as a stabilizer, Pt nanoparticles with sizes of approximate 4–5 nm uniformly disperse on GNP surface. In methanol oxidation reaction, the electrocatalytic activity of Pt/PANI-GNP is nearly 2 times higher than that of Pt/GNP catalyst. Through analysis, it is suggested that the electrocatalysis performance of Pt/PANI-GNP may be improved by the following four factors: (1) uniformly distributed nanoparticle; (2) increased of amount of Pt0 and oxygen-containing groups; (3) the existence of N atoms; (4) difference reaction mechanism. [Copyright &y& Elsevier]

ABSTRACT Ternary Ni-Mo-P thin films have been electrodeposited from citrate-based electrolyte onto graphite substrates for application as anode catalysts for ethanol electrooxidation. The operating deposition parameters were optimized to produce Ni-Mo-P alloy films of outstanding catalytic activity. The phase structure of the deposits was evaluated employing X-ray diffraction technique. Morphology and chemical composition of the deposited alloy films were studied using scanning electron microscopy and energy-dispersive X-ray analysis, respectively. The results demonstrated that the rate of Ni-Mo-P deposition increases with increasing the ammonium molybdate concentration in the plating electrolyte up to 10 g l−1. Also, the amount of Mo in the deposits increases with increasing the ammonium molybdate concentration up to 7.5 g l−1, and the maximum Mo content in the film was 9.1 at.%. The catalytic activity of Ni-Mo-P/C alloy films has been evaluated towards electrooxidation of ethanol in 1.0 M NaOH solution by using cyclic voltammetry and chronoamperometry. The catalytic performance of the prepared anodes as a function of the amount of Mo was studied. The results showed an increase in the oxidation peak current density of ethanol with increasing the Mo at.% in the deposited alloy films. Additionally, Ni-Mo-P/C electrodes displayed significantly improved catalytic activity and stability towards electrooxidation of ethanol compared with that of Ni-P/C electrode. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: The electrooxidation of carbon monoxide on platinum in the presence of anions is one of the very few strictly potentiostatic oscillators, in which the electrode potential takes the role of a parameter rather than an essential variable. In this paper we investigate the oscillatory behavior as a function of five parameters: applied voltage, rotation rate of the electrode, anion concentration, electrolyte resistance and external resistor. The experiments exhibit regular oscillations also in parameter regions in which the hitherto assumed mechanism predicts only the existence of stable fixed points, and they show irregular oscillations in wide parameter ranges. Model considerations reveal that an asymmetric inhibition of the adsorption of CO and OH by adsorbed anions introduces a positive feedback loop. This so far undetected source of oscillations could be responsible for the wide oscillatory range found in the experiments. These oscillations are solely driven by the reaction kinetics and do not involve transport processes or, as the overwhelming number of electrochemical oscillators, an IR drop in the electric circuit. Furthermore, observations are compiled which suggest that the irregular oscillations are a manifestation of spatial pattern formation. [Copyright &y& Elsevier]

Abstract: The electrooxidation of formic acid and methanol on Pt{111} in aqueous sulphuric and perchloric acid as a function of both palladium coverage and Nafion adsorption is reported. Nafion is a proton conducting polymer commonly used as a membrane electrolyte in fuel cells. Understanding the interaction of Nafion with platinum and other bimetallic electrocatalytic surfaces is therefore of crucial importance if one is to optimise fuel cell performance. Here, we demonstrate that for formic acid electrooxidation, Nafion behaves as a weakly adsorbing electrolyte exhibiting similar properties to aqueous perchloric acid. Adsorbed palladium is observed to promote formic acid electrooxidation on Pt{111} and a maximum in electrooxidation rate is found when a single monolayer of palladium on Pt{111} is formed in agreement with previous studies. In contrast, aqueous sulphuric acid strongly inhibits formic acid electrooxidation due to extensive specific adsorption of (bi-)sulphate anions on the palladium adlayer which compete successfully with molecules of formic acid for adsorption sites. In all electrolytes studied, unique electrooxidation peaks ascribable to formic acid electrooxidation occurring on first and second/third layer palladium islands are observed. We ascribe this behaviour to a strong coupling of formic acid adsorption with changes in the local potential of zero total charge as a function of palladium coverage. Hence, it is deduced that Pd/Pt electrocatalysts utilising Nafion membranes should not prove deleterious to electrocatalytic activity. In contrast, similar measurements but using methanol instead of formic acid indicated that methanol electrooxidation is inhibited significantly when Nafion is adsorbed relative to activity recorded in aqueous perchloric acid. In addition, palladium adlayers on Pt{111} are found to inhibit methanol electrooxidation in all electrolytes studied, presumably because the key Cl dissociation step is less favoured on palladium compared to platinum. It is concluded that the role of specifically adsorbed anions is crucial in order to afford optimal fuel cell performance and that for methanol at least, proton conducting membranes other than Nafion should be considered although for formic acid, Nafion appears to be ideal. [Copyright &y& Elsevier]