Spectroelectrochemistry at free-standing carbon nanotubes electrodes

A versatile and low-cost methodology for fabricating free-standing carbon nanotubes (CNT) electrodes for electrochemical and spectroelectrochemical applications is described. The uniformity, flexibility and resistance to bending of these films make them one of the most interesting membranes in a wide range of applications. CNT electrodes were characterized by Raman spectroscopy and scanning electron microscopy and their electrochemical performance was assessed employing various redox species such as ferrocenemethanol, hexacyanoferrate (II) and dopamine. Free-standing single-walled CNT electrodes exhibit good conductivity and transparency to UV–vis radiation, making them suitable as optically transparent electrodes. This is exemplified by monitoring, using UV–vis absorption spectroelectrochemistry, the electrodeposition of gold nanoparticles (AuNPs) on one face of the free-standing CNT electrodes, while the other face remained unmodifiedMinisterio de Economía y Competitividad (CTQ2014-55583-R, CTQ2014-61914-EXP, CTQ2015-71955-REDT) and Junta de Castilla y León (BU033U16)Ministerio de Economía y Competitividad (CTQ2014-55583-R, CTQ2014-61914-EXP, CTQ2015-71955-REDT) and Junta de Castilla y León (BU033U16

Monitoring charge transfer at polarisable liquid/liquid interfaces employing time-resolved Raman spectroelectrochemistry

In-situ Raman spectroscopy is implemented for the first time to monitor dynamic charge transfer processes at polarisable interfaces between two immiscible electrolyte solutions (ITIES) in real time. A custom-designed new electrochemical cell is described which allows probing the Raman signals of ferroin ions as a function of the potential applied across the water|1,2-dichlorobenzene (DCB) interface. This approach is also used for investigating the heterogeneous electron transfer reaction involving dimethylferrocene in DCB and potassium hexacyanoferrate (II/III) in the aqueous phase. The evolution of the Raman signals during potentiodynamic measurements is recorded in real-time with a resolution of a few seconds.Junta de Castilla y Leon (GR71, BU349-U13) and Ministerio de Economia y Competitividad (CTQ2010-17127) is gratefully acknowledged. D.I. thanks Ministerio de Economia y Competitividad for his predoctoral FPI fellowship. D.P. and D.J.F. acknowledge financial support from the EPSRC (grant EP/K007025/1

HISTORICAL RECONSTRUCTION OF HEAVY METAL CONCENTRATION IN THE GULF OF CARIACO, VENEZUELA

<div>210-Pb activity is an useful technique in environmental investigation, to determine sediments accumulation rates, geochronology, and to study metals. Its activity decline exponentially with depth, and is inversely proportional to the</div><div>sedimentation rate at non-impacted ecosystem. Dating of sediments, combined with chemical profile, allow the study of the impact events in coastal zones. In the present study, we have investigated the history of metals concentrations</div><div>and sedimentation rates of recent sediments (100 years) in the Cariaco Gulf, Venezuela (Fig. 1), an important fishery area at the Caribbean Sea, with industrial, harbor, agricultural and urban activities (Fig. 2).</div