Daniel Fabián Rodríguez

Growth control of TiO2 nanotubes in different physical environments

TiO2 nanotubes were fabricated by anodic oxidation of pure titanium substrate in glycerol containing fluoride. Anodisation of the TiO2 foils was carried out in three different conditions: stirring the electrolyte, in a stationary state and air bubbling. For the three conditions mentioned above the formation and dimensions of the resulting nanotubes are detailed. Stirring the electrolyte has proved to be advantageous in comparison with other conditions like air bubbling and stationary state.

Anodization growth of self-organized ZrO2 nanotubes on zircaloy-4. Evaluation of the photocatalytic activity

ZrO2nanotube arrays were prepared through anodic oxidation in glycerol organic electrolyte containing ammonium fluoride. The morphology of these nanotube arrays can be controlled by changing the preparation parameters such as applied voltage, fluoride ion concentration and time of anodization. While the oxidation voltage is the main factor that controls the diameter of nanotubes, the length of nanotubes is mainly depending on the oxidation time, and the crystal type is closely related to the annealing temperature. We also studied their photocatalytic performance. The photocatalytic activity of samples was calculated by the degradation of a model dye, under halogen light illumination.

Gas identification by dynamic measurements of SnO2 sensors

It is well know that the use of chambers with the sensors in the e‐nose improves the measurements, due to a constant gas flow and the controlled temperature sensors[1]. Normally, the chamber temperature is above room temperature due to the heat generated by the heater of sensors. Also, the chamber takes a long time to reach a stable equilibrium temperature and it depends on enviromental conditions. Besides, the temperature variations modify the humidity producing variations in resistance measurements[2]. In this work using a heater system that controls the temperature of the chamber, the desorption process on SnO2 sensor array was study[3]. Also, it was fitted the data signal sensors using a two exponential decay functions in order to determine the desorbing constant process. These constants were used to classify and identify different alcohols and their concentrations.