A Self-Assembled Organic/Metal Junction for Water Photo-Oxidation.

We report the in situ self-assembly of TTF, TTF•+, and BF4- or PF6- into p-type semiconductors on the surface of Pt microparticles dispersed in water/acetonitrile mixtures. The visible light photoactivation of these self-assemblies leads to water oxidation forming O2 and H+, with an efficiency of 100% with respect to the initial concentration of TTF•+. TTF•+ is then completely reduced to TTF upon photoreduction with water. The Pt microparticles act as floating microelectrodes whose Fermi level is imposed by the different redox species in solution; here predominantly TTF, TTF•+, and HTTF+, which furthermore showed no signs of decomposition in solution.

Electrochemical Reduction of Protic Supercritical CO2 on Copper Electrodes.

The electrochemical reduction of carbon dioxide is usually studied in aqueous solutions under ambient conditions. However, the main disadvantages of this method are high hydrogen evolution and low faradaic efficiencies of carbon-based products. Supercritical CO2 (scCO2 ) can be used as a solvent itself to suppresses hydrogen evolution and tune the carbon-based product yield; however, it has received little attention for this purpose. Therefore, the focus of this study was on the electrochemical reduction of scCO2 . The conductivity of scCO2 was increased through the addition of supporting electrolyte and a cosolvent (acetonitrile). Furthermore, the addition of protic solutions of different pH to scCO2 was investigated. 1 m H2 SO4 , trifluoroethanol, H2 O, KOH, and CsHCO3 solutions were used to determine the effect on current density, faradaic efficiency, and selectivity of the scCO2 reduction. The reduction of scCO2 to methanol and ethanol are reported for the first time. However, methane and ethylene were not observed. Additionally, corrosion of the Cu electrode was noticed.

Inkjet Printing Meets Electrochemical Energy Conversion.

Inkjet printing is a very powerful digital and mask-less microfabrication technique that has attracted the attention of several research groups working on electrochemical energy conversion concepts. In this short review, an overview is given about recent efforts to employ inkjet printing for the search of new electrocatalyst materials and for the preparation of catalyst layers for polymer electrolyte membrane fuel cell applications. Recent approaches of the Laboratory of Physical and Analytical Electrochemistry (LEPA) at the École Polytechnique Fédérale de Lausanne for the inkjet printing of catalyst layers and membrane electrode assemblies are presented and future energy research directions of LEPA based on inkjet printing in the new Energypolis campus in the Canton of Valais are summarized.

Critical View on graphene oxide production and its transfer to surfaces aiming electrochemical applications.

Graphene and related materials has been studied aiming their use in several applications including electrochemical sensing systems for a large number of different analytes. However, there have been proportionally only a few studies discussing deeply the implications of the different variables that could be tuned in the preparations of these materials for the development of the electrochemical platforms. In this review it is discussed how the size, number of layers, crystallinity and purity of the graphite starting material affects the final graphene oxide (GO) and reduced graphene oxide (rGO) prepared by chemical exfoliation. The exfoliation process and the most frequently applied transfer methods used to prepare thin films of GO and rGO on surfaces/electrodes of sensing platforms are also discussed. The electrochemical behavior of these materials is evaluated as a role of surface organization and adsorption. Considering the parameters previously presented, it is outlined some of the most relevant sensors and biosensor systems, which employ graphene related materials and attempts to explore different possibilities of deposition.

Electrochemical approaches employed for sensing the antioxidant capacity exhibited by vegetal extracts: a review.

Vegetal extracts are among the most important source of polyphenols in the diet, highlighting the importance of their characterization and determination. For this reason, analytical methods have gained increasing interest, with many publications devoted to this subject. Among the wide possibilities of analytical methods, electroanalytical techniques can provide valuable information, since the antioxidant activity of polyphenols is related to their electrochemical properties. This review analyzes and highlights the role of electroanalytical approaches for sensing the antioxidant capacity exhibited by vegetal extracts, as well as focuses on their importance for human health. The analytical capacity of the electrochemistry is comprehensively stated with the selected results found in the literature, mainly from 2000 up to the present date.