Banca de DEFESA: RODRIGO DA SILVA FRANCO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : RODRIGO DA SILVA FRANCO
DATE: 03/11/2022
TIME: 08:30
LOCAL: Instituto de Química
TITLE:

APPLICATION OF CHEMOMETRIC TOOLS IN THE STUDY OF Pd ELECTRODEPOSITION PROCESS IN THE PRESENCE AND ABSENCE OF ULTRASOUND ON MODIFIED DIFFUSION LAYERS

KEY WORDS:

ANOVA-PCA, Electrodeposition, Palladium, factorial design, Ultrasound, Cyclic Voltammetry.

PAGES: 104
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Físico-Química
SPECIALTY: Eletroquímica
SUMMARY:

One of the main challenges in the preparation of gas diffusion electrodes is related with the high cost of platinum that is the main component of the catalytic layer. In this context, palladium is an interesting candidate to substitute platinum, partially or completely, due to its lower cost, higher abundance and good catalytic activity on reactions using hydrogen. In this study, the electrodeposition of palladium was investigated by using electrochemical techniques assisted by ultrasound. The electrochemical deposition was studied by using a factorial design 2^4-1 as a chemometric tool, aiming to reduce the number of experiments and estimate the effects of interactions between the variables. The investigated variables were the number of deposition cycle (NDC = 100 and 300 cycles); scan rate (SR = 50 and 100 mV s^-1); Pd²⁺ concentration ([Pd²⁺] = 0.5 and 1.0.10^-3 mol L^-1) and in the absence or presence of ultrasound waves (US, 100 W). The electrochemically active surface area (ECSA) was used as response. According with the study every variables were significant, the US, NDC, SR and the [Pd²⁺], with the US presenting more significance. Some second and third order interactions were also significant. The best condition evaluated was that performed with higher NDC, [Pd²+], in lower SR and in the presence of ultrasound. Through the application of the ANOVA-PCA technique, it was possible to observe that all variables contribute to a change in the profile of the observed voltammetric responses, especially in the peak related to the hydrogen desorption process. Morphological and structural analyzes by scanning electron microscopy (SEM), scanning electron microscopy by field emission generated by an electron gun (FEG), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS) were performed. In general, it was possible to verify that the use of ultrasound during the Pd electrodeposition process promoted an increase in the amount of electrodeposited Pd, affecting the morphology of the agglomerated nanoparticles, which seem to promote an increase in ECSA

COMMITTEE MEMBERS:
Interno - 1698441 - RENNAN GEOVANNY OLIVEIRA ARAUJO
Interno - 2362069 - RAILDO ALVES FIUZA JUNIOR
Externa ao Programa - 1091039 - SILVANA MATTEDI E SILVA - UFBAExterno ao Programa - 1160224 - GABRIEL CHRISTIANO DA SILVA - UFBAExterno à Instituição - GIANCARLO RICHARD SALAZAR BANDA - UNIT
Externo à Instituição - Francisco Trivinho Strixino - UFSCAR
Externo à Instituição - Vinicius Del Colle - UFAL