Assessment of atomic layer deposited TiO2 photocatalytic self-cleaning by quartz crystal microbalance

The self-cleaning properties emerging from photocatalytic effects consist in the elimination of an organic contamination layer by light-induced redox reactions. Quartz crystal microbalances (QCMs), monitoring the contaminant mass loss under UV illumination, were used to investigate this effect and its efficiency. A new setup dedicated to such purpose is introduced along with the results of a self-cleaning experiment performed with a 20-nm TiO2 thin film coated on a QCM by atomic layer deposition. In particular, a 10-nm paraffin oil thin film deposited under vacuum is shown to be degraded down to its complete removal according to a zeroth order photocatalytic reaction. Finally, the experimental opportunities offered by the new setup, such as a controlled environment composition, are presented.Peer reviewe

MnO 2 Thin Films on 3D Scaffold: Microsupercapacitor Electrodes Competing with “Bulk” Carbon Electrodes

International audienceA simple, binder-free fabrication of high capacitance electrodes based on manganese dioxide (MnO2) thin films is reported. The 3D structure of these electrodes significantly improves the areal capacitance of the MnO2 thin films up to 670 mF cm−2 in aqueous electrolyte, which is 4.5 times higher than the best reported capacitance of 3D electrodes thus far. This capacitance is on the same order of magnitude as that of a bulk carbon electrode. Moreover, the 3D MnO2-based electrode exhibits a stable cycling behavior for more than 15 000 cycles

Du document au dossier : changement de paradigme dans la formation en archivistique au Bénin

Le programme de formation en archivistique mis en place au début des années 1980 en République du Bénin s’est inspiré du modèle élaboré au lendemain de la Révolution française et longtemps mis en oeuvre par l’École nationale des chartes. Une évaluation récente a révélé trois absences fondamentales dans l’enseignement : 1) compétences en gestion des documents actifs ; 2) normes de description archivistique ; et 3) outils d’indexation matière. En réponse, un nouveau programme de formation a été conçu.L’article décrit les difficultés rencontrées dans la gestion des archives dans l’administration et dans les entreprises au Bénin, et la solution qu’apporte l’Université d’Abomey-Calavi.The archival training program implemented in the early 1980s in the Republic of Benin was inspired by the model developed in the aftermath of the French Revolution and long implemented by the École nationale des chartes. A recent evaluation revealed three fundamental gaps in teaching : 1) skills in active records management ; 2) archival description standards ; and 3) subject indexing tools. In response, a new training program has been developed.The article describes the difficulties encountered in the management of archives in government and businesses in Benin, and the solution provided by the University of Abomey-Calavi

Asymmetric electrochemical capacitor microdevice designed with vanadium nitride and nickel oxide thin film electrodes

Vanadium nitride thin film has been coupled with electrodeposited nickel oxide in order to design an electrochemical capacitor microdevice. VN has been used as negative electrode while NiO was used as the positive one in 1 M KOH electrolyte. VN exhibits a pseudo-capacitive behavior while NiO shows a faradaic behavior. This asymmetric microdevice has been operated between 0.5 and up to 1.8 V in aqueous based electrolyte (1 M KOH). Long term cycling ability (10,000 charge/discharge cycles) has been demonstrated with interesting energy (1.0 μW h cm−2) and power (40 mW cm−2) densities. Keywords: Electrochemical capacitor, Supercapacitor, Microdevice, Vanadium nitride, Nickel oxid