Banca de DEFESA: NADJA SOUSA DE OLIVEIRA

Statistical tools in the development of ultrasound-assisted Pt/Ti catalytic materials for the glycerol electro-oxidation. 

electrochemistry, glycerol, statistical tools, ultrasound

Nowadays the demand for alternative sources in substitution of fossil and pollutant energy sources is growing fast. Biodiesel is an important alternative on this scenario with its production increasing each year. This process generates 10 wt% of glycerol as co-product. Since glycerol supply has become higher than its demand in the last decade, research on ways of glycerol valorization have grown markedly, specially through electrocatalytic routes. This work presents a study on the use of chemometric tools and other statistical analyzes to evaluate and improve the conditions of Pt deposition on Ti electrodes using electrochemical techniques. In addition, the catalytic activities toward glycerol electrooxidation on the different electrodeposits obtained were examined by cyclic voltammetry and chronoamperometry in acid media. A 2³ factorial design was used, where the parameters chosen were: number of deposition cycles (NDC – 40 and 60 cycles), scan rate (SR – 100 and 200 mV s^-1 ) and presence and absence of ultrasound (US, 100 W). The electrochemically active surface area (ECSA) was used as response.  The X-ray diffraction peaks indicated the typical character of the platinum fcc structure. The voltammetric profiles of the Pt/Ti for different experimental conditions are similar to that of the typical polycrystalline pure Pt. According with the chemometric results the presence of US, SR, NDC and the interaction between US and SR were significant variables. The best condition evaluated was that performed with higher NDC, in lower SR and in the presence of ultrasound. The results indicate that the ECSA estimated is approximately 2.9 times higher for the Pt obtained with US (in the best condition), when compared to the results obtained without ultrasound. Pt electrodeposits presented promising results for the glycerol electrooxidation process, in which the highest values of current peak were reached in the ultrasound-assisted measurements