Optimizing PtSn composition in direct sugarcane extract fuel cells

Abstract

Pt90Sn10/C composition exhibited a strong maximum power density value and a good sugar oxidation response in sugar extract solution in comparison with others electrocatalysts prepared. Pt90Sn10/C demonstrated a maximum power density approximately 93% higher than that of Pt80Sn20/C, which is the second most active material and more than 8 times bigger than Pt/C. The primary difference between the two lies in glucose consumption, which is approximately 90% higher in Pt90Sn10/C. It is important to highlight that in the more active materials; fructose consumption remains relatively constant, ranging between 7 and 8%. The enhanced performance could be attributed to both the altered electronic properties resulting from tin integration into the platinum crystal lattice and the activation of water at less positive potentials by a bifunctional mechanism. XRD results showed that the lattice parameters were expanded indicating the insertion of Sn to Pt, while that cyclic voltammetry showed that all materials present the hydrogen adsorption–desorption region over Pt (− 0.2 to 0.15 V); however, when increasing the tin content in the catalyst, the region decreases the definition and is associated with the presence of transition metals such as Sn. TEM images and histograms for PtSn showed the increase in the average particle size accompanying the tin enrichment in the composition; this effect could be tin oxide in material surface and is in agreement with other works.