Centro de Investigación y Desarrollo Tecnológico en Electroquímica

About: Centro de Investigación y Desarrollo Tecnológico en Electroquímica is a based out in . It is known for research contribution in the topics: Cyclic voltammetry & Catalysis. The organization has 537 authors who have published 682 publications receiving 10382 citations. The organization is also known as: Centro de Investigacion y Desarrollo Tecnologico en Electroquimica & Center of Research and Technologic Development in Electrochemistry.

Reversible photochromic effect in the TiO2—polymer hybrid system

Abstract: The photochromism of poly methyl methacrylate–TiO2 composites have been investigated in this research. Amorphous titanium oxide was synthesized by sol–gel using titanium isopropoxide. The titanium solution was mixed with a dissolved polymer. The composite shows photo-response under UV radiation by changing, generally, to a dark brown tonality. This effect was reversible in different time ranges according to the intensity and exposure time. The mechanism for this photochromic change was proposed as a reduction of TiOOH domains to Ti3+ and not directly from amorphous TiO2, which provide electron-hole pairs after absorbing UV. The backscattered electrons image shows the clusters or domains of titanium compounds as white dots, ranging from 0.1 to 1 μm. The electron spin resonance spectroscopy signals indicated a titanium valence change from Ti(IV) to Ti(III). The X-ray photoelectron spectroscopy peaks positions for Ti 2p1/2 and Ti 2p3/2 were assigned as Ti4+. The values were obtained for Ti 2p3/2 and the identified species were Ti4+ and Ti3+, that correspond to TiO2, Ti2O3, and Ti(OOH). Few and small crystalline domains were identified by Transmission Electron Microscope as orthorhombic TiO2.’