pinecone/core-2020-05-10-deduplication huggingface dataset:
Cr-doped La-Ni-O catalysts derived from perovskite precursors for CH4-CO2 reforming under microwave irradiation

The nickel catalysts derived from Cr-doped LaNiO perovskite-like precursors were characterized by X-ray diffraction, high-resolution transmission electron microscopy, temperature-programmed oxidation, temperature-programmed reduction, and X-ray photoelectron spectroscopy. Their catalytic performance in CO reforming of methane under microwave irradiation was investigated. It was found that the structure and morphology of the oxide composites in this research were influenced by the ratio of Ni and Cr, and the mismatch of La, Ni, and Cr may cause phase segregation. The catalytic performance of the Ni catalysts is dependent on the oxygen mobility of the perovskite oxide matrix, the content of the reduced Ni, and the content of the remaining perovskite structure. The mobile oxygen in the perovskite matrix in the catalyst may enhance the conversion of CO during the reaction
Transferring Electrochemical CO2 Reduction from Semi-Batch into Continuous Operation Mode Using Gas Diffusion Electrodes

The electrochemical reduction of C02 is a promising method for its conversion which still suffers from important challenges that have to be solved before indus­ trial realization becomes attractive. The optimization of gas diffusion electrodes is described with respect to catalyst dispersion and mass transport limitations allowing solubility issues to be circumvented and current densities to be increased to industrially relevant values. The transfer of the promising results from semi-batch experiments into continuous mode of operation is demonstrated, and it is indi­cated how the energetic efficiency can be significantly improved by the choice of electrolyte, in terms of concentration and type. Thereby ohmic losses can be decreased and the intrinsic activity be improved
Impact of Aeration on Mixed Liquor in Submerged-Membrane Bioreactors for Wastewater Treatment

In submerged-membrane bioreactors (SMBRs) for wastewater treatment, aeration with coarse bubbles is applied to limit fouling. The understanding of the different mechanisms between aeration and fouling helps to manage the aeration policy. The impact of aeration (macro scale) on shear stress and mixed-liquor properties (local scale) is evaluated. Experimental characterization of gas-liquid flow in membrane modules, computational fluid dynamics simulation, and controlled breakdown of SMBR mixed-liquor samples are reported. Mean bubble velocities were significantly lower in mixed liquor than in water and the shear stress was one order of magnitude higher in mixed liquor than in water. The floc size decreased and soluble protein concentrations increased with higher shear stress values. Considering the known impacts of these mixed-liquor properties on fouling, the obtained local results explain stronger fouling when coarse bubble aeration increases
Adsorption of C1-C4 alcohols, C4-C5 isoolefins and their corresponding ethers over Amberlyst™35

An experimental liquid- and gas-phase adsorption study of C1-C4 alcohols, C4-C5 isoolefins, and the tert-alkyl ethers obtained thereof over Amberlyst¿35 is presented. Liquid-phase adsorption experiments were performed in a batch adsorber and gas-phase adsorption experiments were carried out in a packed-bed adsorber in a defined temperature range. Adsorption entropy and enthalpy were determined from adsorption equilibrium constants of each tracer in both liquid and gas phase. Adsorption equilibrium constants of alcohols were found to be larger than those of isoolefins and ethers. The moment technique was used to estimate micro- and macropore effective diffusion coefficients of the involved species
Effects of Process Parameters on an Inverse Concentrated Miniemulsion Flowing in a Microchannel

Emulsions are of great industrial interest due to their wide variety and end‐use properties. Microfluidics systems provide excellent control of transport phenomena. Hence, the influence of operating parameters on a concentrated inverse miniemulsion flowing in a microfluidic system was investigated. The feasibility of maintaining the emulsion in a microfluidic device was clearly demonstrated and the associated operating domain identified. Due to its influence on rheology, the effect of temperature on the droplet size distribution was quantified. Under specific conditions, a mass transfer phenomenon between the train of water drops and the smallest droplets of the emulsion was found, potentially explained by a difference in osmotic pressure between the two aqueous phases
Exploiting the facile oxidation of evaporated gold films to drive electroless silver deposition for the creation of bimetallic Au/Ag surfaces

Gold is often considered as an inert material but it has been unequivocally demonstrated that it possesses unique electronic, optical, catalytic and electrocatalytic properties when in a nanostructured form.[1] For the latter the electrochemical behaviour of gold in aqueous media has been widely studied on a plethora of gold samples, including bulk polycrystalline and single-crystal electrodes, nanoparticles, evaporated films as well as electrodeposited nanostructures, particles and thin films.[1b, 2] It is now well-established that the electrochemical behaviour of gold is not as simple as an extended double-layer charging region followed by a monolayer oxide-formation/-removal process. In fact the so-called double-layer region of gold is significantly more complicated and has been investigated with a variety of electrochemical and surface science techniques. Burke and others[3] have demonstrated that significant processes due to the oxidation of low lattice stabilised atoms or clusters of atoms occur in this region at thermally and electrochemically treated electrodes which were confirmed later by Bond[4] to be Faradaic in nature via large-amplitude Fourier transformed ac voltammetric experiments. Supporting evidence for the oxidation of gold in the double-layer region was provided by Bard,[5] who used a surface interrogation mode of scanning electrochemical microscopy to quantify the extent of this process that forms incipient oxides on the surface. These were estimated to be as high as 20% of a monolayer. This correlated with contact electrode resistance measurements,[6] capacitance measurements[7] and also electroreflection techniques..
Liquid|liquid interfacial photoelectrochemistry of chromoionophoreI immobilised in 4-(3-phenylpropyl)pyridine microdroplets

Photoelectrochemical processes are investigated for chromoionophoreI (ETH 5294) dissolved in 4-(3-phenylpropyl)pyridine (PPP) and deposited in the form of a microdroplet array (through evaporation deposition from a solution in acetonitrile) onto a 5mm diameter basal plane pyrolytic graphite (BPPG) electrode. Stable biphasic dark voltammetric responses (two electron/two proton) are observed in phosphate buffer solution (from pH2 to 12) with a switch in reactivity at pH5 due to a biphasic protonation step. The photoelectrochemical activity at pH2 is investigated further by phototransient amperometry. The protonated chromoionophoreI is shown to be the photoactive component (supported by EPR data) and "hole transfer" at the liquid|liquid interface to aqueous oxalate is demonstrated. This interfacial hole-transfer process can be "switched off" by hydrophobic anions (PF6-), which compete for cationic liquid|liquid PPP surface binding sites. Implications for light harvesting and liquid semiconductor properties are discussed
Diffusion-Recombination Impedance Model for Solar Cells with Disorder and Nonlinear Recombination

The diffusion–recombination model is a key tool in understanding the photovoltaic operation of solar cells. Dye-sensitized solar cells, organic solar cells, and inorganic semiconductor solar cells are systems affected by disorder that are often characterized with impedance spectroscopy. In this paper, we extend the previous theory of diffusion–recombination impedance including traps and nonlinear recombination. We show the transmission line equivalent circuit representation, and we describe the physical meaning of a number of model parameters that can be obtained: the chemical capacitance, ; the recombination resistance, ; the transport resistance, ; the electron lifetime, ; the electron conductivity, ; the chemical diffusion coefficient of electrons, ; and the diffusion length, . At most, three of these parameters are independent, but if the diffusion length is short, the impedance model collapses to a function that has one degree of freedom less, known as the Gerischer impedance. We show the connection of the two parameters that remain to the diffusion length and the lifetime
Shape-Dependent Electrocatalysis: Oxygen Reduction on Carbon-Supported Gold Nanoparticles

Cubic, octahedral and quasi-spherical (two different particle sizes) Au nanoparticles are synthesised and dispersed in a carbon-black powder. The size and morphology of the Au nanocatalysts is confirmed by transmission electron microscopy and X-ray diffraction. Au nanospheres are approximately 5 and 30 nm in diameter, whereas the size of Au octahedra and nanocubes is approximately 40–45 nm. The electrocatalytic activity of these carbon-supported particles towards the oxygen reduction reaction (ORR) is studied in 0.5 M H2SO4 and 0.1 M KOH solutions by using the rotating-disk-electrode method. The specific activity (SA) for O2 reduction is measured, and the highest SA is observed for Au nanocubes supported on carbon. The highest mass activities are found for the smallest Au nanoparticles. Tafel analysis suggests that the mechanism of the ORR on shape-controlled Au/C catalysts is the same as on bulk Au.This research was financially supported by institutional research funding (IUT 20–16) of the Estonian Ministry of Education and Research and by the Estonian Research Council (Grant No. 8380), by Archimedes Foundation (Project No. 3.2.0501.10–0015), by the MCINN-FEDER (Spain) (project CTQ 2010–16271) and by the Generalitat Valenciana (project PROMETEO/2009/045)
Use of Diode Analogy in Explaining the Voltammetric Characteristics of Immobilized Ferrocenyl Moieties on a Silicon Surface

Article first published online: 15 SEP 2014The creation of a model that explains the dependency of the voltammetric characteristics of ferrocene-terminated Si (Si-Fc) samples on the type of substrate (n- or p-type) would be helpful in understanding the electronic characteristics of these materials. To explain the dependency, Si-Fc samples are treated like diodes. As diodes, the samples may allow charge flow in a certain direction while inhibiting the opposite flow. The treatment of a sample as a diode is done to facilitate analysis of charge flow within the sample, thus enabling easy prediction of its electrochemical characteristics. Likewise, the trend of the anodic peak potential versus light intensity plot (of the samples with n-type substrate) is also associated with the sample’s diode characteristics. Our proposed model opens many scientific possibilities, especially in relating the voltammetric characteristics of electroactive molecules on a Si surface with the properties of a diode (e.g., open-circuit voltage)
Correlation of the Electrochemical Kinetics of High-Salinity-Tolerant Bioanodes with the Structure and Microbial Composition of the Biofilm

Increasing the conductivity of the electrolytes used in microbial electrochemical systems is an essential prerequisite to large‐scale application of these technologies. Microbial anodes formed on carbon felt from a salt marsh inoculum under polarisation at 0.1 V (versus a saturated calomel electrode), generated up to 85 A m−2 in media that contained 30–45 g L−1 of NaCl. Analyses of microbial populations showed a stringent selection of the two microbial genera Marinobacter and Desulfuromonas. Currents decreased if NaCl concentration was increased to 60 g L−1. This highest salinity was shown to consistently impact the bioanode performance in three ways: voltammetry indicated degraded electron‐transfer kinetics, confocal laser scanning microscopy showed a modified biofilm structure and DNA pyrosequencing detected a decrease in the level of Desulfuromonas spp. relative to Marinobacter spp. A consistent correlation was, thus, found between electrochemical kinetics, biofilm structure and the composition of the microbial community
Proof of concept of the electrochemical sensing of 3-iodothyronamine (T1AM) and Thyronamine (T0AM)

Recent studies have shown that, besides the well-recognized T-3 and T-4 hormones, there are other relevant thyroid hormones circulating in the human body. In particular, this is the case for 3-iodothyronamine (T(1)AM) and thyronamine (T(0)AM). One of the reasons for the lack of studies showing their precise importance is the absence of analytical methodologies available. Herein, for the first time, T(1)AM and T(0)AM are electrochemically characterized. T(0)AM was sensed by means of a glassy carbon electrode; furthermore, T(1)AM was sensed both with a graphitic surface (oxidatively) as well as with mercury (reductively). For both compounds, after oxidation, it was possible to observe the reversible redox reaction concerning the benzoquinone/hydroquinone couple, thus increasing the specificity of the electroanalysis. Therefore, this work provides the basis for an at-point-of-use' electrochemical strip test for T(1)AM and T(0)AM
Oil|Water Interfacial Phosphate Transfer Facilitated by Boronic Acid: Observation of Unusually Fast Oil|Water Lateral Charge Transport

Anion transfer for highly hydrophilic phosphate and hydroxide anions into a water-immiscible organic phase, 3-(4-phenylpropyl)-pyridine (or PPP), is driven with the tetraphenylporphyrinato manganese(II/III) (or TPPMn) redox system and facilitated with a hydrophobic oil-based boronic acid ((3-(1,3-dioxo-6-propylamino-1H-benzo[de]isoquinolin-2(3 H)-yl)phenyl)boronic acid). Both 1) experiments with random arrays of microdroplets (transient) and 2) experiments in a gold–gold dual-plate oil-filled microtrench generator-collector configuration (approaching steady state), show that phosphate transfer is facilitated by boronic acid. At pH 7.5 a switch in mechanism occurs from phosphate transfer to hydroxide transfer. Accelerated charge transport is observed lateral to the oil|water interface. Improved boronic acid facilitators and nanotrench electrodes are discussed in terms of future feasibility for phosphate sensing applications
Paving the Way towards Highly Stable and Practical Electrolytes for Rechargeable Magnesium Batteries

Despite being considered a promising anode candidate for future battery technologies, the reactivity of Mg metal and its resultant passivation have challenged the development of electrolytes for rechargeable Mg batteries. In this Concept article, we shed light on critical past and current motivations, hurdles, and design strategies of electrolyte development for Mg batteries. Special focus is given to the most recent advancements; in particular, we elaborate on bottom‐up design strategies targeted to overcome the corrosion issue caused by current electrolyte systems. Salts containing the BH motif expanded the portfolio of Mg‐compatible electrolytes and are used as a platform to create a whole new promising family. Here, we explain the approach, challenges, and the path forward for ultimately creating Mg‐compatible, highly stable, and non‐corrosive Mg electrolytes.Enhancing electrolytes: A platform to design electrolytes for rechargeable Mg batteries based on the BH motif has generated a new family of highly promising and noncorrosive electrolytes. The principles that guided the design of state‐of‐the‐art Mg electrolytes and their properties are discussed. In addition, a bottom‐up design approach based on BH compounds is described
Cathodic corrosion of Cu substrates as a route to nanostructured Cu/M (M = Ag, Au, Pd) surfaces

The electrochemical formation of nanostructured materials is generally achieved by reduction of a metal salt onto a substrate that does not influence the composition of the deposit. In this work we report that Ag, Au and Pd electrodeposited onto Cu under conditions where galvanic replacement is not viable and hydrogen gas is evolved results in the formation of nanostructured surfaces that unexpectedly incorporate a high concentration of Cu in the final material. Under cathodic polarization conditions the electrodissolution/corrosion of Cu occurs which provides a source of ionic copper that is reduced at the surface-electrolyte interface. The nanostructured Cu/M (M = Ag, Au and Pd) surfaces are investigated for their catalytic activity for the reduction of 4 nitrophenol by NaBH4 where Cu/Ag was found to be extremely active. This work indicates that a substrate electrode can be utilized in an interesting manner t  make bimetallic nanostructures with enhanced catalytic activity
Ferrocene-boronic acid–fructose binding based on dual-plate generator–collector voltammetry and square-wave voltammetry

The interaction of ferrocene-boronic acid with fructose is investigated in aqueous 0.1 M phosphate buffer at pH 7, 8 and 9. Two voltammetric methods, based on 1) a dual-plate generator–collector micro-trench electrode (steady state) and 2) a square-wave voltammetry (transient) method, are applied and compared in terms of mechanistic resolution. A combination of experimental data is employed to obtain new insights into the binding rates and the cumulative binding constants for both the reduced ferrocene-boronic acid (pH dependent and weakly binding) and for the oxidised ferrocene-boronic acid (pH independent and strongly binding)
Electrochemical Oxidation of Small Organic Molecules on Au Nanoparticles with Preferential Surface Orientation

The surface orientation effect on the oxidation of small organic molecules such as methanol, formaldehyde, ethanol, and glycerol has been studied on Au nanoparticles in alkaline medium. Two sets of Au nanoparticles enriched in (100) and (111) facets were synthetized by using colloidal methods in presence of cetyltrimethylammonium bromide. The nanoparticles were physically characterized by using TEM and XRD and electrochemically characterized by using Pb underpotential deposition as a surface-structure probe. It is reported that, although methanol oxidation was similar in both types of nanoparticles, the oxidation of formaldehyde presented a clear surface orientation effect. For this reaction, nanoparticles with (111) preferential orientation presented higher current densities at low potentials, whereas Au(100) nanoparticles exhibited higher activity at potentials more positive than 1.0 V versus RHE. On the other hand, for glycerol and ethanol oxidations, the onset of the reaction was similar in both types of particles, although Au(111) nanoparticles showed higher current densities than the Au(100) ones.P.R. acknowledges financial support from the Netherlands Organization for Scientific Research (NWO) through a VENI grant and the University of Birmingham through a Birmingham Fellowship
Evidence of Local pH Changes during Ethanol Oxidation at Pt Electrodes in Alkaline Media

Local changes of the interfacial pH can significantly affect the rate and mechanism during the course of an electrodic reaction. For instance, different pH values will have a significant effect on the equilibrium properties of both solution and surface species, altering the reactions kinetics. Ethanol oxidation at platinum electrodes in alkaline media involves the fast consumption of OH− species that will change the local pH at the electrode surface, decreasing the reaction rate. In this study, the local pH change during ethanol oxidation in alkaline media is accomplished by using rotating ring-disc electrode (RRDE) experiments. The current at the ring when polarized at the onset of hydrogen evolution serves as a measure of the local pH in the vicinity of the electrode. The results show that the current at the ring at 0.1 V (vs. RHE) becomes more negative during ethanol oxidation, owing to a change in the equilibrium potential of the hydrogen evolution reaction caused by a change in the local pH.Financial support from Aalto University, Academy of Finland, MINECO, and Generalitat Valenciana through projects CTQ2013–44083-P and PROMETEOII/2014/013 is acknowledged
Polyanilines with pendant amino groups as electrochemically active copolymers at neutral pH

One of the most promising fields of application of polyaniline (PANI)-based modified electrodes is the construction of biosensors. However, PANI itself is not electroactive in neutral media. This problem can be solved by copolymerization of aniline with other monomers. Herein, we present a study of the electrosynthesis and electrochemical performance of copolymer films of 3-aminobenzylamine and aniline. These films are both stable and electroactive in acid and neutral media. They can even be employed as mediators of ascorbic acid oxidation, showing variable electrocatalytic activity depending on the copolymer composition. The presence of different proportions of pendant amino groups was confirmed by using XPS. These groups are responsible for the increased electroactivity in neutral solution. The copolymer films studied here can be used as versatile building blocks in the construction of bioelectroactive assemblies.Fil: Marmisollé, Waldemar Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de La Plata; ArgentinaFil: Gregurec, Danijela . Soft Matter Nanotechnology Group. CIC BiomaGUNE; EspañaFil: Moya, Sergio . Soft Matter Nanotechnology Group. CIC BiomaGUNE; EspañaFil: Azzaroni, Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de La Plata; Argentin
Local Electrochemical Measurements in Bipolar Experiments for Corrosion Studies

In this work, the local potential and local current were measured with paired Ag/AgCl reference microelectrodes during the corrosion of a 304L stainless-steel (304L SS) sample in bipolar experiments. During a single experiment, it was possible to investigate both the anodic and cathodic domains corresponding to the corrosion of the stainless steel. From these local measurements in non-contact mode, the current/potential curve was obtained, revealing the different reactivities of the 304L SS sample, over a large potential range. The polarisation curve was similar to that usually obtained in a classical three-electrode configuration