Pt and PtSn catalysts supported on activated carbon from amazonian biomass for ethanol electro-oxidation
摘要
The use of carbonaceous materials derived from biomass, such as those used to support platinum-based catalysts in fuel cells, has increased in recent years due to their advantages regarding sustainability and the circular economy. These biomass-derived materials, whose physicochemical characteristics, such as porosity and surface area, can be controlled through thermal and chemical activation, have become increasingly popular. This study obtained activated carbon by chemically treating biomass residues of tucumã, which was then used as a support for platinum and platinum-tin nanoparticle catalysts. These catalysts were evaluated for the electrochemical oxidation of ethanol. The activated carbon exhibited predominantly acidic functional groups, especially carboxylic (4.158 mM g−1) and carbonyl (3.447 mM g−1) groups, rather than basic groups (4.525 mM g−1). Additionally, the catalysts displayed reflections typical of the face-centered cubic structure of polycrystalline platinum at 39.2° and 45.7° (2θ), corresponding to the (111) and (200) planes, respectively. Lastly, this study found a significant correlation between ethanol concentration and peak current density, with an asymptotic increase in current for both catalysts as ethanol concentration increased. Interestingly, the PtSn/AC catalyst showed a slight decrease in current density from 8.44 mA cm−2 at 0.8 mol L−1 ethanol to 8.24 mA cm−2 at 1.0 mol L−1 ethanol.