Palladium nanoparticles supported on carbon Vulcan XC72 (Pd/C) and biocarbon (Pd/BC) synthesized by sodium borohydride process were used as catalysts for ethanol electro-oxidation in alkaline media. The biocarbon (BC) from coconut shell with mesoporous and high surface area (792 m 2 g −1) was obtained by carbonization at 900 °C and the hydrothermal treatment in a microwave oven. The D-band and G-band intensity ratio (I D /I G) from Raman analysis showed high disorder of the biocarbon, while X-ray photoelectron spectroscopy (XPS) suggests higher percentage of oxygen groups on the surface of biocarbon than of Vulcan XC72. From X-ray diffraction (XRD), it was observed peaks in 2θ degree related to the face centered cubic (fcc) structure of palladium and the mean crystallite sizes calculated based on the diffraction peak of Pd (220) were 5.6 nm for Pd/C and 5.3 nm for Pd/BC. Using Transmission Electron Microscope (TEM), it was observed particles well dispersed on both carbons support materials. The electrocatalytic activity of the materials was investigated by cyclic voltammetry (CV) and chronoamperometry (CA) experiments. The peak current density (on CV experiments) from ethanol electro-oxidation on Pd/BC was 50% higher than on Pd/C, while the current density measured at 15 min of CA experiments was 80% higher on Pd/BC than on Pd/C. The higher catalytic activity of Pd/BC might be related to the large surface area of the biocarbon (792 m 2 g −1) vs (239 m 2 g −1) of Vulcan carbon, the defects of the biocarbon structure and higher amount of oxygen on the surface than Carbon Vulcan XC 72.
The overuse of non-renewables resources in the last decades has generated negative consequences for the society, which have boosting the search for mitigating the damage caused in the environment. Aiming to contribute to the expansion of the strategies to control the pollutants in the environment thought the development of low-cost technologies, the mean goal of present work is to develop active materials with high thermic resistance and suitable specific area to adsorption and impregnation of metals. In this regard, it was studied three different routes of treatment of the biocarbons. The biocarbons materials were characterized by infrared spectroscopy (IR), Raman spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TG), and Brunauer–Emmett–Teller analysis (BET). The three different strategies of treatment resulted in changes in the carbonaceous structure of the biocarbon, resulting in suitable characteristics for support material for catalysts, such as activities sites with negative charge to promote the attachment of the metals on the carbon surface. It was also observed the enhancement of the specific surface area, that ranges from 341.4 to 749.7 m2 g-1, changes of D and G band of carbon and high temperature resistance, which promote catalytic reactions with catalyst loss.
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