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Abstract: RuO2 nanoparticles are synthesized by Instant method using Li2CO3 as stabilizing agent, under microwave irradiation at 60°C and investigated for the anodic oxygen evolution reaction (OER) and for their supercapacitance properties in 0.5M H2SO4 medium. Structural and morphological characterizations of RuO2 are investigated by in situ X-ray diffraction (XRD), thermogravimetric analysis (TG-DTA), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDS) and Raman spectroscopy. The TEM images of as prepared material show the uniform distribution of RuO2 nanoparticles with mean diameter of ca. 1.5nm. Analysis on as prepared material indicates the structural formula as [RuO2·2.6H2O] 0.7H2O with low crystallinity. The influence of annealing temperature on RuO2 is studied in light of electrocatalytic activity for oxygen evolution reaction (OER) and capacitance. Electrochemical performances of RuO2 electrodes are followed by current–potential curves, galvanostatic charge–discharge cycles and evolved oxygen measurements. The amount of oxygen gas evolved during the OER by the crystalline RuO2 is found to be consistent with the electrical energy supplied to the catalyst. The cyclic voltammogram of RuO2 exhibits the typical capacitance behavior with highly reversible nature. The specific capacitance of hydrous RuO2 is found to be 737Fg−1 at the scan rate of 2mVs−1, by the balanced transport of proton through the structural water and electron transport along dioxo bridges, which makes a suitable material for energy storage. The specific capacitance decreases with increase in the crystallinity of RuO2. The present study shows the potential method to synthesize rapid and uniform nano particles of RuO2 for water electrolysis and supercapacitors. [Copyright &y& Elsevier]

Abstract: The electrochemical activation of glucose was studied at the surface of gold particles prepared either by magnetron sputtering or water-in-oil microemulsion methods. At lower potentials smaller sputtered electrocatalysts (i.e. with Feret’s diameter lower than 5 nm) involved a remarkable activity, which was likely due to their electronic structures. It was suggested that the enhancement of the electrocatalytic performances at the surface of the electrodes composed of largest particles could be related to the formation of “sticking defects” in the nanomaterials. [Copyright &y& Elsevier]

Abstract: The catalytic activity of single chamber solid oxide fuel cells (SC-SOFCs) with respect to hydrocarbon fuels induces a major overheating of the fuel cell, temperature variations along its length, and changes in the original fuel/air composition mainly over the anode component. This paper assesses the temperature gradients and the variations in performance along electrolyte-supported Ni-YSZ/YSZ/LSM cells fed with methane gas. The investigations are performed in a useful range of CH4/O2 ratios between 1.0 and 2.0, in which the furnace temperature and flow rate of methane–air mixtures are held constant at 700°C and 450sccm, respectively. Electrochemical impedance spectroscopy (EIS) is used to sense the temperature at the location where smaller size cathodes are positioned on the opposite side of a full-size anode. Due to temperature increases, cells always perform better when the small cathodes are located at the inlet as well as at a CH4/O2 ratio of 1.0. With an increase in ratio, the results show the presence of artefacts due to the use of an active LSM material for the combustion of methane, and open-type gas distribution plates for the single chamber reactor. [Copyright &y& Elsevier]

Niobium-added titanium oxide is a promising candidate as a substitute carbon support for cathodes of PEFCs. Nb-added TiO 2 can act as a support for platinum nanoparticles to enhance the oxygen reduction reaction (ORR) activity and durability under acidic conditions. Nb-added TiO 2 supports with the desired surface area (10–130 m2 g−1) and conductivity (10−7–10−2 S cm−1) were prepared by changing the amount of Nb and the heat treatment conditions. First, we conducted a systematic investigation with changes in the amount of niobium addition, heat-treatment temperature, and time under a pure hydrogen atmosphere to reveal the physicochemical factors that govern the surface area and conductivity. Finally, we successfully proposed a procedure to prepare highly durable Nb-added TiO 2 supports with the desired surface area and conductivity by controlling the amount of niobium addition, heat-treatment temperature, and time under hydrogen. The charges of the double layer were almost unchanged after 5000 cycles of an accelerated durability test (ADT). [Display omitted] • Design of Nb-added TiO 2 as cathode supports for polymer electrolyte fuel cells. • Control of specific surface area and conductivity of Nb-added TiO 2 • Specific surface area was strongly affected by the amount of Nb addition. • Conductivity was governed by the ratio of Nb4+. • Superior durability of Nb-added TiO 2 in acidic and oxidative atmosphere. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cellulosic biomass-based glucose is selectively oxidized in a co-generation direct fuel cell. • Real-time evidence of glucose oxidation in fuel cell by C1-position to gluconate (90% selectivity). • Glucuronate production (10% selectivity) via the glucose oxidation at the C6-position. • Products distribution in direct alkaline glucose fuel cell is the same as in half-cell setup. Cellulosic biomass, which is basically a polymer of glucose, is the most abundant organic polymer on earth and there is significant interest in the development of advanced materials for its valorization through the waste-to-energy and water-to-chemical scenarios. Hence, a precise investigation of the monomer (glucose) electrooxidation in electrochemical reactors is a key starting point to tackle the whole cellulose and ultimately the entire biomass. To this end, we report herein new insights about the operation of a cogeneration direct alkaline glucose fuel cell (which includes an anion exchange membrane) that simultaneously produces electricity and mainly gluconate as the reaction product. The AuPt nanocatalysts of 3–5 nm particle size finely dispersed onto reduced graphene oxide (rGO) at a 20 wt% metal loading are obtained from an organic surfactant-free method, so-called the bromide anion exchange (BAE). Specifically, the electroanalytical investigation carried out with high-performance liquid ionic chromatography (HPLIC) and liquid chromatography coupled to mass spectrometry (LC-MS) demonstrate no carbon–carbon bond cleavage occurs, which represents an advance towards a CO 2 -free biomass valorization process. The comparison of the results commonly obtained in a three-electrode half-cell with those in an anion exchange membrane fuel cell shows that the trends in selectivity are the same. The fuel cell operation produces gluconate via a two-electron transfer process at 90% selectivity and 65% Faradaic efficiency. In addition to gluconate, glucuronate is also observed; both compounds are high value-added chemicals. This work contributes towards the engineering of novel electrocatalytic interfaces for the valorization of the surplus biomass into energy and chemicals. [ABSTRACT FROM AUTHOR]

The composition of essential oils varies according to culture conditions and climate, which induces a need for simple and inexpensive characterization methods close to the place of extraction. This appears particularly important for developing countries. Herein, we develop an analytical strategy to determine the thymol content in Ocimum Gratissimum, a medicinal plant from Benin. The protocol is based on electrochemical techniques (cyclic and square wave voltammetry) implemented with a low cost potentiostat. Thymol is a phenol derivative and was directly oxidized at the electrode surface. We had to resort to submillimolar concentrations (25-300 μM) in order to minimize production of phenol oligomers that passivate the electrode. We worked first on two essential oils and realized that in one of them the thymol concentration was below our detection method. These results were confirmed by gas chromatography - mass spectrometry. Furthermore, we optimized the detection protocol to analyze an infusion made directly from the leaves of the plant. Finally, we studied whether the cost of the electrochemical cell may also be minimized by using pencil lead as working and counter electrodes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Hydrogen peroxide (H 2 O 2 ) is a key chemical for many industrial applications, yet it is primarily produced by the energy-intensive anthraquinone process. As part of the Power-to-X scenario of electrosynthesis, the controlled oxygen reduction reaction (ORR) can enable the decentralized and renewable production of H 2 O 2 . We have previously demonstrated that self-supported electrocatalytic materials derived from polyaniline by chemical oxidative polymerization have shown promising activity for the reduction of H 2 O to H 2 in alkaline media. Herein, we interrogate whether such materials could also catalyze the electro-conversion of O 2 -to-H 2 O 2 in an alkaline medium by means of a selective two-electron pathway of ORR. To probe such a hypothesis, nine sets of polyaniline-based materials were synthesized by controlling the polymerization of aniline in the presence or not of nickel (+II) and cobalt (+II), which was followed by thermal treatment under air and inert gas. The selectivity and faradaic efficiency were evaluated by complementary electroanalytical methods of rotating ring-disk electrode (RRDE) and electrolysis combined with spectrophotometry. It was found that the presence of cobalt species inhibits the performance. The selectivity towards H 2 O 2 was 65-80% for polyaniline and nickel-modified polyaniline. The production rate was 974 ± 83, 1057 ± 64 and 1042 ± 74 µmol H2O2 h -1 for calcined polyaniline, calcined nickel-modified polyaniline and Vulcan XC 72R (state-of-the-art electrocatalyst), respectively, which corresponds to 487 ± 42, 529 ± 32 and 521 ± 37 mol kg -1 cat h -1 (122 ± 10, 132 ± 8 and 130 ± 9 mol kg -1 cat cm -2 ) for faradaic efficiencies of 58-78%.

Copper-supported mesoporous carbon nanocatalysts (Cu/FDU-15) were synthesized using an easy and convenient one-pot soft-template method for low-overvoltage CO 2 electroreduction. TEM imaging revealed the presence of large Cu nanoparticles (diameter 140 nm) with Cu 2 O nanoparticles (16 nm) as an additional phase. From the electron tomography observations, we found that the copper particles were placed inside and on the exterior surface of the porous FDU-15 support, providing an accessible surface for electrocatalytic reactions. CO 2 electrolyses showed that the mesostructured Cu/FDU-15-350 cathode materials were active towards CO 2 conversion to formic acid with 22 % Faradaic efficiency at a remarkably low overpotential of 290 mV, hydrogen being the only side-product. The catalyst's activity correlates to the calculated metallic surface area, as determined from a geometrical model, confirming that the mesoporous channels act as a diffusion path for the CO 2 molecule, and that the whole Cu surface is accessible to CO 2 , even if particles are entrapped in the carbon matrix., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

This work reports on the facile synthesis and characterisation of a non-precious-metal bifunctional catalyst for oxygen reduction and evolution reactions (ORR and OER). A few-layer reduced graphene oxide-supported NiCo 2 O 4 catalyst is prepared using a rapid and easy two-step method of synthesis. It consists of the solvothermal poyl(vinylpyrrolidone)-assisted assembly of metal complexes onto few-layer graphene followed by a calcination step aiming at converting metal complexes into the spinel phase. Using this synthesis approach, the most active material demonstrates an outstanding activity towards the OER and ORR, making it one of the best bifunctional catalysts of these reactions ever reported. This composite catalyst exhibits improved bifunctional behaviour with a low reversibility criterion of 746 mV. The ORR process follows a four-electron pathway and the hydroxyl selectivity is higher than those with pure reduced graphene oxide or NiCo 2 O 4 materials, showing the synergistic effect between the two phases. Moreover, the high activity of this composite catalyst is confirmed by comparing its performance with those obtained on other cobaltite catalysts prepared using a different synthesis method, or those obtained using a different graphene-based support., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

This review presents in a comprehensive ways the chemical methods used to functionalize gold nanoparticles with focus on anti-cancer applications. The review covers the parameters required for the synthesis gold nanoparticles with defined shapes and sizes, method for targeted delivery in tumours, and selected examples of anti-cancers compounds delivered with gold nanoparticles. A short survey of bioassays for oncology based on gold nanoparticles is also presented., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)