Electrodeposition of Gold Nanostructures at the Interface of a Pickering Emulsion

The controlled electrodeposition of nanoparticles at the surface of an emulsion droplet offers enticing possibilities in regards to the formation of intricate structures or fine control over the locus or duration of nanoparticle growth. In this work we develop electrochemical control over the spontaneous reduction of aqueous phase Au(III) by heterogeneous electron trans-fer from decamethylferrocene present in an emulsion droplet –resulting in the growth of nanoparticles. As gold is a highly effective conduit for the passage of electrical current, even on the nanoscale, the deposition significantly enhances the current response for the single electron transfer of decamethylferrocene when acting as a redox indicator. The nanostructures formed at the surface of the emulsion droplets were imaged by cryo-TEM,providing an insight into the types of structures that may form when stabilised by the interface alone, and how the structures are able to conduct electrons

Dating Archaeological Strata in the Magna Mater Temple Using Solid-state Voltammetric Analysis of Leaded Bronze Coins

[EN] The application of solid state electrochemistry techniques for dating archaeological strata using lead-containing bronze coins is described. The proposed methodology was applied to samples coming from the Roman archaeological site of Magna Mater Temple (Rome, Italy) occurring in different strata dating back between the second half and the end of the 4(th) century A.D. and the 20(th) century. The voltammetric signatures of copper and lead corrosion products in contact with aqueous acetate buffer, as well as the catalytic effects produced on the hydrogen evolution reaction, were used for establishing the age of different strata and dating coins belonging to unknown age. Voltammetric data were consistent with a theoretical approximation based on a potential rate law for the corrosion process.Financial support from the MINECO Projects CTQ2014-53736-C3-1-P and CTQ2014-53736-C3-2-P which are supported with ERDF funds is gratefully acknowledged. PhD grants of the Department of Earth Sciences, Sapienza University of Rome, are gratefully thanked.Di Turo, F.; Montoya, N.; Piquero-Cilla, J.; De Vito, C.; Coletti, F.; Favero, G.; Domenech Carbo, MT.... (2018). Dating Archaeological Strata in the Magna Mater Temple Using Solid-state Voltammetric Analysis of Leaded Bronze Coins. Electroanalysis. 30(2):361-370. https://doi.org/10.1002/elan.201700724S36137030

Electrochemical fingerprint of archaeological lead silicate glasses from the voltammetry of microparticles approach

[EN] The application of a solid-state electrochemical technique, voltammetry of microparticles (VMP), for studying archeological lead glass is described. Upon attachment to graphite electrodes immersed into aqueous acetate buffer, characteristic voltammetric profiles were obtained for submicrosamples of archeological glasses dated between the 9th and 19th centuries. Bivariate and multivariate chemometric analyses of the VMP data allowed us to characterize individual workshops/provenances which enabled a clear discrimination between soda-rich and potash-rich glasses. An analysis of the VMP data, combined by XRF, FESEM, AFM and ATR-FTIR and Micro-Raman spectroscopies, denoted the presence of Pb(IV) centers accompanying network-former and network-modifier Pb(II).Financial support from the MINECO Projects CTQ2014-53736-C3-1-P, CTQ2014-53736-C3-2-P and MAT2015-65445-C2-2-R, which are supported with ERDF funds is gratefully acknowledged. Likewise financial support of the Comunidad de Madrid and structural funds of the EU through Programa Geomateriales 2 ref. S2013/MIT-2914 is acknowledged. The authors thank the Seccion de Investigacion Arqueologica Municipal de Valencia for kindly authorizing sampling to carry out this research. The authors also thank Dr. Jose Luis Moya Lopez and Mr. Manuel Planes Insausti (Microscopy Service of the Universitat Politecnica de Valencia) for their technical support.Doménech Carbó, A.; Villegas Broncano, MÁ.; Martínez Ramírez, S.; Domenech Carbo, MT.; Martínez Pla, B. (2016). Electrochemical fingerprint of archaeological lead silicate glasses from the voltammetry of microparticles approach. Journal of the American Ceramic Society. 99(12):3915-3923. https://doi.org/10.1111/jace.14430S391539239912Dumbaugh, W. H., & Lapp, J. C. (1992). Heavy-Metal Oxide Glasses. Journal of the American Ceramic Society, 75(9), 2315-2326. doi:10.1111/j.1151-2916.1992.tb05581.xKurkjian, C. R., & Prindle, W. R. 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Journal of Archaeological Science, 54, 168-181. doi:10.1016/j.jas.2014.11.036Kunicki-Goldfinger, J. J., Freestone, I. C., McDonald, I., Hobot, J. A., Gilderdale-Scott, H., & Ayers, T. (2014). Technology, production and chronology of red window glass in the medieval period – rediscovery of a lost technology. Journal of Archaeological Science, 41, 89-105. doi:10.1016/j.jas.2013.07.029Stevenson, C. M., Gleeson, M., & Novak, S. W. (2014). The surface hydration of soda-lime glass and its potential for historic glass dating. Journal of Archaeological Science, 52, 293-299. doi:10.1016/j.jas.2014.08.027Henderson, J., Evans, J. A., Sloane, H. J., Leng, M. J., & Doherty, C. (2005). The use of oxygen, strontium and lead isotopes to provenance ancient glasses in the Middle East. Journal of Archaeological Science, 32(5), 665-673. doi:10.1016/j.jas.2004.05.008Nord, A. G., Billström, K., Tronner, K., & Olausson, K. B. (2015). Lead isotope data for provenancing mediaeval pigments in Swedish mural paintings. Journal of Cultural Heritage, 16(6), 856-861. doi:10.1016/j.culher.2015.02.009SCHIAVON, N., CANDEIAS, A., FERREIRA, T., DA CONCEIÇAO LOPES, M., CARNEIRO, A., CALLIGARO, T., & MIRAO, J. (2012). A COMBINED MULTI-ANALYTICAL APPROACH FOR THE STUDY OF ROMAN GLASS FROM SOUTH-WEST IBERIA: SYNCHROTRON μ-XRF, EXTERNAL-PIXE/PIGE AND BSEM-EDS. Archaeometry, 54(6), 974-996. doi:10.1111/j.1475-4754.2012.00662.xVERWEIJ, H., & KONIJNENDIJK, W. L. (1976). Structural Units in K2O-PbO-SiO2 Glasses by Raman Spectroscopy. Journal of the American Ceramic Society, 59(11-12), 517-521. doi:10.1111/j.1151-2916.1976.tb09422.xMorikawa, H., Takagi, Y., & Ohno, H. (1982). Structural analysis of 2PbO·SiO2 glass. Journal of Non-Crystalline Solids, 53(1-2), 173-182. doi:10.1016/0022-3093(82)90027-8Imaoka, M., Hasegawa, H., & Yasui, I. (1986). X-ray diffraction analysis on the structure of the glasses in the system PbOSiO2. 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Leaching of Lead and Connectivity of Plumbate Networks in Lead Silicate Glasses. Journal of the American Ceramic Society, 88(10), 2908-2912. doi:10.1111/j.1551-2916.2005.00508.xWedepohl, K. H., & Simon, K. (2010). The chemical composition of medieval wood ash glass from Central Europe. Geochemistry, 70(1), 89-97. doi:10.1016/j.chemer.2009.12.006Janssens, K. (Ed.). (2013). Modern Methods for Analysing Archaeological and Historical Glass. doi:10.1002/9781118314234Doménech-Carbó, A., Labuda, J., & Scholz, F. (2012). Electroanalytical chemistry for the analysis of solids: Characterization and classification (IUPAC Technical Report). Pure and Applied Chemistry, 85(3), 609-631. doi:10.1351/pac-rep-11-11-13Doménech-Carbó, A., Doménech-Carbó, M. T., & Costa, V. (Eds.). (2009). Electrochemical Methods in Archaeometry, Conservation and Restoration. Monographs in Electrochemistry. doi:10.1007/978-3-540-92868-3DOMÉNECH-CARBÓ, A., DOMÉNECH-CARBÓ, M. T., PEIRÓ-RONDA, M. A., & OSETE-CORTINA, L. (2011). ELECTROCHEMISTRY AND AUTHENTICATION OF ARCHAEOLOGICAL LEAD USING VOLTAMMETRY OF MICROPARTICLES: APPLICATION TO THE TOSSAL DE SANT MIQUEL IBERIAN PLATE. Archaeometry, 53(6), 1193-1211. doi:10.1111/j.1475-4754.2011.00608.xDoménech-Carbó, A., Doménech-Carbó, M. T., & Peiró-Ronda, M. A. (2011). Dating Archeological Lead Artifacts from Measurement of the Corrosion Content Using the Voltammetry of Microparticles. Analytical Chemistry, 83(14), 5639-5644. doi:10.1021/ac200731qDoménech-Carbó, A., Doménech-Carbó, M. T., Peiró-Ronda, M. A., Martínez-Lázaro, I., & Barrio-Martín, J. (2012). Application of the voltammetry of microparticles for dating archaeological lead using polarization curves and electrochemical impedance spectroscopy. Journal of Solid State Electrochemistry, 16(7), 2349-2356. doi:10.1007/s10008-012-1668-9Doménech-Carbó, A., Sánchez-Ramosa, S., Doménech-Carbó, M. T., Gimeno-Adelantado, J. V., Bosch-Reig, F., Yusá-Marco, D. J., & Saurí-Peris, M. C. (2002). Electrochemical Determination of the Fe(III)/Fe(II) Ratio in Archaeological Ceramic Materials Using Carbon Paste and Composite Electrodes. Electroanalysis, 14(10), 685. doi:10.1002/1521-4109(200205)14:103.0.co;2-4Doménech-Carbó, A., Doménech-Carbó, M. T., Gimeno-Adelantado, J. V., Moya-Moreno, M., & Bosch-Reig, F. (2000). Voltammetric Identification of Lead(II) and (IV) in Mediaeval Glazes in Abrasion-Modified Carbon Paste and Polymer Film Electrodes. Application to the Study of Alterations in Archaeological Ceramic. Electroanalysis, 12(2), 120-127. doi:10.1002/(sici)1521-4109(200002)12:23.0.co;2-eDoménech-Carbó, A., Doménech-Carbó, M. T., & Osete-Cortina, L. (2001). Identification of Manganese(IV) Centers in Archaeological Glass Using Microsample Coatings Attached to PolymerFilm Electrodes. Electroanalysis, 13(11), 927-935. doi:10.1002/1521-4109(200107)13:113.0.co;2-9Doménech-Carbó, A., Doménech-Carbó, M. T., & Mas-Barberá, X. (2007). Identification of lead pigments in nanosamples from ancient paintings and polychromed sculptures using voltammetry of nanoparticles/atomic force microscopy. Talanta, 71(4), 1569-1579. doi:10.1016/j.talanta.2006.07.053SHUGAR, A. N. (2000). BYZANTINE OPAQUE RED GLASS TESSERAE FROM BEIT SHEAN, ISRAEL. Archaeometry, 42(2), 375-384. doi:10.1111/j.1475-4754.2000.tb00888.xPavlov, D., & Monakhov, B. (1987). Effect of Sb on the electrochemical properties of Pb/PbSO4/H2SO4 and Pb/PbO/PbSO4/H2SO4 electrodes. Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 218(1-2), 135-153. doi:10.1016/0022-0728(87)87012-2Pavlov, D., Monakhov, B., Maja, M., & Penazzi, N. (1989). Mechanism of Action of Sn on the Passivation Phenomena in the Lead‐Acid Battery Positive Plate (Sn‐Free Effect). Journal of The Electrochemical Society, 136(1), 27-33. doi:10.1149/1.2096603Cai, W.-B., Wan, Y.-Q., Liu, H.-T., & Zhou, W.-F. (1995). A study of the reduction process of anodic PbO2 film on Pb in sulfuric acid solution. Journal of Electroanalytical Chemistry, 387(1-2), 95-100. doi:10.1016/0022-0728(94)03866-2Komorsky-Lovrić, Š., Lovrić, M., & Bond, A. M. (1992). Comparison of the square-wave stripping voltammetry of lead and mercury following their electrochemical or abrasive deposition onto a paraffin impregnated graphite electrode. Analytica Chimica Acta, 258(2), 299-305. doi:10.1016/0003-2670(92)85105-fDe Keersmaecker, M., Dowsett, M., Grayburn, R., Banerjee, D., & Adriaens, A. (2015). In-situ spectroelectrochemical characterization of the electrochemical growth and breakdown of a lead dodecanoate coating on a lead substrate. Talanta, 132, 760-768. doi:10.1016/j.talanta.2014.10.035Meyer, B., Ziemer, B., & Scholz, F. (1995). In situ X-ray diffraction study of the electrochemical reduction of tetragonal lead oxide and orthorhombic Pb(OH)Cl mechanically immobilized on a graphite electrode. 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The structure of glasses and crystalline compounds in the system PbOSiO2, studied by X-ray photoelectron spectroscopy. Journal of Non-Crystalline Solids, 48(2-3), 423-430. doi:10.1016/0022-3093(82)90177-6Matson, D. W., Sharma, S. K., & Philpotts, J. A. (1983). The structure of high-silica alkali-silicate glasses. A Raman spectroscopic investigation. Journal of Non-Crystalline Solids, 58(2-3), 323-352. doi:10.1016/0022-3093(83)90032-7Mysen, B. O., & Frantz, J. D. (1994). Silicate melts at magmatic temperatures: in-situ structure determination to 1651�C and effect of temperature and bulk composition on the mixing behavior of structural units. Contributions to Mineralogy and Petrology, 117(1), 1-14. doi:10.1007/bf00307725Götz, J., Hoebbel, D., & Wieker, W. (1976). Silicate groupings in glassy and crystalline 2PbO·SiO2. Journal of Non-Crystalline Solids, 20(3), 413-425. doi:10.1016/0022-3093(76)90122-8Lee, S. K., & Stebbins, J. F. (2003). Nature of Cation Mixing and Ordering in Na-Ca Silicate Glasses and Melts. The Journal of Physical Chemistry B, 107(14), 3141-3148. doi:10.1021/jp027489yRobinet, L., Bouquillon, A., & Hartwig, J. (2008). Correlations between Raman parameters and elemental composition in lead and lead alkali silicate glasses. Journal of Raman Spectroscopy, 39(5), 618-626. doi:10.1002/jrs.1894Colomban, P., & Treppoz, F. (2001). Identification and differentiation of ancient and modern European porcelains by Raman macro- and micro-spectroscopy. Journal of Raman Spectroscopy, 32(2), 93-102. doi:10.1002/jrs.678Robinet, L., Coupry, C., Eremin, K., & Hall, C. (2006). The use of Raman spectrometry to predict the stability of historic glasses. Journal of Raman Spectroscopy, 37(7), 789-797. doi:10.1002/jrs.1540Robinet, L., Coupry, C., Eremin, K., & Hall, C. (2006). Raman investigation of the structural changes during alteration of historic glasses by organic pollutants. 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On-line database of voltammetric data of immobilized particles for identifying pigments and minerals in archaeometry, conservation and restoration (ELCHER database)

[EN] A web-based database of voltammograms is presented for characterizing artists' pigments and corrosion products of ceramic, stone and metal objects by means of the voltammetry of immobilized particles methodology. Description of the website and the database is provided. Voltammograms are, in most cases, accompanied by scanning electron microphotographs, X-ray spectra, infrared spectra acquired in attenuated total reflectance Fourier transform infrared spectroscopy mode (ATR-FTIR) and diffuse reflectance spectra in the UV-Vis-region. For illustrating the usefulness of the database two case studies involving identification of pigments and a case study describing deterioration of an archaeological metallic object are presented. (C) 2016 Elsevier B.V. All rights reserved.Research was conducted within the "Grupo de analisis cientifico de bienes culturales y patrimoniales y estudios de ciencia de la conservacion" Microcluster of the University of Valencia Excellence Campus. Financial support is gratefully acknowledged from the MINECO Projects CTQ2014-53736-C3-1-P and CTQ2014-53736-C3-2-P which are also supported with ERDF funds. The authors would like to thank to Gonzalo Girones Sarrio manager of GongDisseny Co. by the technical support for building the site structure and the structure of the database, Archbishop of Valencia, Dr. Ignacio Bosch Reig and Dr. Pilar Roig Picazo directors of the intervention project in the Basilica de la Virgen de los Desamparados de Valencia, the conservator Estrella Arcos Von Haartman (Quibla Restaura Company) and City Council Town of Malaga, the Museum of Archaeology of Xativa, its director Angel Velasco and the conservators Isabel Martinez Lazaro and Betlem Martinez for facilitating access to samples as well as Manuel Planes Insausti and Dr Jose Luis Moya Lopez technical supervisors of the Electron Microscopy Service of the Universitat Politecnica de Valencia where were carried out SEM-EDX analyses.Domenech-Carbo, A.; Domenech Carbo, MT.; Valle-Algarra, FM.; Gimeno-Adelantado, J.; Osete Cortina, L.; Bosch-Reig, F. (2016). On-line database of voltammetric data of immobilized particles for identifying pigments and minerals in archaeometry, conservation and restoration (ELCHER database). Analytica Chimica Acta. 927:1-12. https://doi.org/10.1016/j.aca.2016.04.052S11292

Theory of Square-Wave Voltammetry of Two-Electron Reduction with the Adsorption of Intermediate

Thermodynamically unstable intermediate of fast and reversible two-electron electrode reaction can be stabilized by the adsorption to the electrode surface. In square-wave voltammetry of this reaction mechanism, the split response may appear if the electrode surface is not completely covered by the adsorbed intermediate. The dependence of the difference between the net peak potentials of the prepeak and postpeak on the square-wave frequency is analyzed theoretically. This relationship can be used for the estimation of adsorption constant