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An iridium oxide (IrOx)-functionalized carbon rod or platinum coil was employed as the anode for metal electrodeposition in a protic amide-type ionic liquid (IL) containing metal oxides, ensuring the sustainability of the system by replacing the decomposition of the IL with an oxygen evolution reaction (OER). [ABSTRACT FROM AUTHOR]

Abstract: The voltammetric behavior of cuprous ions has been studied at disk electrodes of glassy carbon and polycrystalline platinum in a new hydrophilic 1-butyl-3-methylimidazolium salicylate ionic liquid (BMI-SAL IL). Cuprous ions Cu(I) were introduced into the IL by the anodic dissolution of a Cu wire electrode or by the addition of CuCl. This air- and water-stable hydrophilic IL is very similar to dicyanamide (DCA)-based ILs because both DCA anions and salicylate (SAL) anions have very strong ligand properties; therefore, many metal salts, such as metal halides, are very soluble in this IL. However, the source of SAL anions, sodium salicylate, is considerably cheaper than sodium dicyanamide salt. The potentiostatic electrodeposition of copper onto iron substrates has also been investigated in this study. The surface morphologies of the copper deposits were significantly altered by the electrodeposition potential; granular, mirror-like, and porous copper deposits could be obtained at different negative potentials. The activity of the copper deposit-modified iron electrodes toward the electrochemical nitrate reduction in alkaline solutions was found to significantly depend on the surface morphologies. The granular and the porous surfaces showed better activities. The mirror-like surface, however, had no activity on the electrochemical nitrate reduction. [Copyright &y& Elsevier]

Abstract: In this study, the voltammetric behavior of Pd(II), Ni(II), and mixtures of Pd(II) and Ni(II) was carried out in room-temperature N-butyl-N-methylpyrrolidinium dicyanamide ionic liquid (BMP-DCA IL). Electrodeposition of PdNi bimetal was achieved by controlled-potential electrolysis at iron wire electrodes from BMP-DCA containing various molar ratios of PdCl2/NiCl2. BMP-DCA shows good solubilities to PdCl2 and NiCl2, respectively, leading to the convenience for preparing the electrodepositing baths. By tuning the molar ratios of Pd(II)/Ni(II) in the electrodepositing baths and/or the applied potentials, PdNi coatings with various atomic contents of Pd could be obtained. Among these PdNi bimetallic coatings, the PdNi coatings with atomic ratios of ∼80/20 had the highest oxidation current in methanol oxidation reaction (MOR) in 1M NaOH and exhibited the best poisoning tolerance. Powder X-ray diffraction analysis indicated that two separate metallic phases belonging to Pd and Ni existed in the PdNi coatings. The diffraction signal of Pd was very broad, indicating the tiny crystal size of Pd in the bimetal coatings. The scanning electron spectroscopic micrographs of PdNi coatings demonstrated that the Pd∼80Ni∼20 coatings had three-dimensional structures. This morphological characteristic implied that the composition and the surface morphology of the PdNi coatings equivalently contributed to the electrocatalytic activity toward MOR. The Pd∼80Ni∼20-coated iron-electrode (Fe/Pd∼80Ni∼20) was used to detect methanol and the linearity was observed in 3.53μM to 758.88μM using hydrodynamic chronoamperometry where a potential of −0.1V (vs. Ag/AgCl) was applied. [Copyright &y& Elsevier]

Abstract: Nonenzymatic electrochemical determination of ethanol and glucose was respectively achieved using PdNi- and Pd-coated electrodes prepared by electrodeposition from the novel metal-free ionic liquid (IL); N-butyl-N-methylpyrrolidinium dicyanamide (BMP-DCA). BMP-DCA provided an excellent environment and wide cathodic limit for electrodeposition of metals and alloys because many metal chlorides could dissolve in this IL where the reduction potentials of Pd(II) and Ni(II) indeed overlapped, leading to the convenience of potentiostatic codeposition. In aqueous solutions, the reduction potentials of Pd(II) and Ni(II) are considerably separated. The bimetallic PdNi coatings with atomic ratios of ∼80/20 showed the highest current for ethanol oxidation reaction (EOR). Ethanol was detected by either cyclic voltammetry (CV) or hydrodynamic amperometry (HA). Using CV, the dependence of EOR peak current on concentration was linear from 4.92 to 962μM with a detection limit of 2.26μM (σ =3), and a linearity was observed from 4.92 to 988μM using HA (detection limit 0.83μM (σ =3)). The Pd-coated electrodes prepared by electrodeposition from BMP-DCA showed electrocatalytic activity to glucose oxidation and CV, HA, and square-wave voltammetry (SWV) were employed to determine glucose. SWV showed the best sensitivity and linearity was observed from 2.86μM to 107μM, and from 2.99mM to 10.88mM with detection limits of 0.78μM and 25.9μM (σ =3), respectively. For glucose detection, the interference produced from ascorbic acid, uric acid, and acetaminophen was significantly suppressed, compared with a regular Pt disk electrode. [ABSTRACT FROM AUTHOR]

The electrochemistry of cesium was investigated at mercury electrodes in the tri-1-butylmethylammonium bis((trifluoromethyl)sulfonyl)imide (Bu3MeN+Tf2N-) room-temperature ionic liquid (RTIL) by using cyclic staircase voltammetry, rotating disk electrode voltammetry, and chronoamperometry. The reduction of cesium ions at mercury exhibits quasireversible behavior with k0 = 9.8 × 10-5cms-1 and α = 0.36. The diffusion coefficient of Cs+ in this RTIL was 1.04 × 10-8cm2s-1 at 303K. Bulk deposition/stripping experiments conducted at a rotating mercury film electrode gave an average recovery of 97% of the electrodeposited Cs. The density, absolute viscosity, and equivalent conductance of Bu3MeN+Tf2N- were measured over the range of temperatures from 298 to 353K. A polynomial equation describing the temperature dependence of the density is presented. Both the viscosity and conductance exhibited the non-Arrhenius temperature dependence typical of glass-forming liquids. The ideal glass transition temperature and the activation energies for viscosity and conductance were obtained by fitting the Vogel–Tammann–Fulcher (VTF) equation to the experimental data for these transport properties. [Copyright &y& Elsevier]

Cu and CuPb electrodes were prepared via electrodeposition from a hydrophobic protic amide-type ionic liquid, the protonated betaine bis((trifluoromethyl)sulfonyl)amide ([Hbet][TFSA]), and water mixture containing CuO/PbO as the metal sources under ambient air rather than inert atmosphere. The possible coordination structure and the voltammetric behavior of the metal ions were carefully studied. The electrodeposited Cu electrodes showed steady activity towards nitrate reduction, and the activity depended on the electrodeposition potential. The dependence might be due to the change of surface morphologies of Cu with the electrodepositing potentials. The activity was markedly enhanced once Pb was doped into the electrodeposits (CuPb). The bulk electrolysis of nitrate indicated that the key step nitrite formation occurred during the electrocatalytic reduction, and nitrite could be further reduced to other nitrogen species. The electrodeposited CuPb electrodes exhibited the potential to be used as the electrocatalysts of nitrate reduction and/or nitrate sensor. Image 1 • CuO and PbO were dissolved in a protic hydrophobic amide-type ionic liquid (IL). • Electrochemical and spectroscopic features of Cu(II) and Pb(II) were studied. • Potentiostatic electrodeposition was used to prepare Cu and CuPb electrodes. • Both electrodes showed electrocatalytic activity towards nitrate reduction. • Pb doping significantly altered the surface morphologies and reaction current. [ABSTRACT FROM AUTHOR]

Abstract: Macroporous silver films, ordered or fragmented, were fabricated by electrodeposition of silver into the interstitial spaces of templates formed by polystyrene (PS) latex spheres that had been self-assembled onto bare indium tin oxide (ITO) electrodes or onto gold-coated ITO (ITO/Au) electrodes (in which the electrode had been coated by gold sputtering deposition) from two room-temperature ionic liquids (ILs): N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (BMP-TFSI) and N-butyl-N-methylpyrrolidinium dicyanamide (BMP-DCA), respectively, under normal atmospheric conditions. After electrodeposition of silver, the PS spheres were removed by dissolution in tetrahydrofuran (THF) to leave a macroporous silver structure. The higher wettability of ILs onto PS spheres leads to improved penetration of the ILs into the cavities of the PS templates. Electrodeposition is easier if an electrolyte that has a good penetration into the interstitial spaces between the PS spheres. The macroporous silver electrode exhibited much better electrocatalytic performance with respect to nitrate reduction than a regular silver wire electrode. Quantitative determination of nitrate was also examined. [Copyright &y& Elsevier]

Free sulfide anion (S 2− ) in alkaline media was determined using cathodic stripping voltammetry (CSV) and a graphene oxide-modified screen-printed carbon electrode (SPCE/GO) electrodeposited with Ag, Au, or AuAg nanoparticles (NPs). Electrodeposition was achieved using cyclic voltammetry in dilute sulfuric acid containing AgNO 3 and/or HAuCl 4 ·4H 2 O in which thiourea was essential for stabilizing Ag + . The existence of GO resulted in higher density and more uniform distribution of NPs, compared with those electrodeposited on bare SPCE. The composite electrode SPCE/GO/AgNPs showed the greatest sensitivity but poorest reproducibility. The SPCE/GO/AuNPs, in contrast, showed the best reproducibility with a linear dynamic range of S 2− from 6.25 to 400 μM and no significant interference from various inorganic anions and cations. EDTA, however, was essential to eliminate the interfering effects from metal cations. By co-depositing Au and Ag to form SPCE/GO/AuAgNPs, the sensitivity was significantly improved in contrast to SPCE/GO/AuNPs, and the reproducibility was approximately reserved. By using differential-pulse CSV (DPCSV), a linear dynamic range of 0.05∼1.5 μM was observed. A wider but two-segmented dynamic range, 0.5∼12.5 and 12.5∼312.5 μM, was obtained by using liner-scan CSV (LSCSV). SPCE/GO/AuAgNPs, however, showed a poorer resistance against metal cationic interferents, compared with SPCE/GO/AuNPs, although EDTA was used. This study reveals a facile approach of preparing sensitive modified electrodes for the determination of S 2− in alkaline aqueous media. [ABSTRACT FROM AUTHOR]

Abstract: Cuprous iodide (CuI) thin films with photoelectrochemical activity were prepared by anodizing copper wire or copper-electrodeposited tungsten wire in the room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMI-PF6 RTIL) containing N-butyl-N-methylpyrrolidinium iodide (BMP-I). A copper coating was formed on the tungsten wire by potentiostatic electrodeposition in BMP-dicyanamide (BMP-DCA) RTIL containing copper chloride (CuCl). The CuI films formed using this method were compact, fine-grained and exhibited good adhesion. The characteristic diffraction signals of CuI were observed by powder X-ray diffractometry (XRD). X-ray photoelectron spectroscopy (XPS) also confirmed the formation of a CuI compound semiconductor. The CuI films demonstrated an apparent and stable photocurrent under white light illumination in aqueous solutions and in a RTIL. This method has enabled the electrochemical formation of CuI from a RTIL for the first time, and the first observation of a photocurrent produced from CuI in a RTIL. The coordinating strength of the anions of the RTIL is the key to the successful formation of the CuI thin film. If the coordinating strength of the anions of the RTIL is too strong, no CuI formation is observed. [Copyright &y& Elsevier]