Effect of different zeolite as Pt supports for methanol oxidation reaction

In this work, we investigate the effect of zeolite-carbon composite as support of Pt (Pt/zeolite-carbon) on the electrocatalytic activity for methanol oxidation reaction (MOR) in acid media. Three different zeolites were evaluated: faujasite (FAU), merlinoite (W) and analcime (ANA). Zeolite-carbon substrate and Pt nanoparticles were synthesized by sol gel and ultrasound, methods, respectively. FAU zeolite exhibits higher specific surface area constituted by micro and mesoporosity compared to ANA and W zeolites, which are characterized by their mesoporous structure. TEM results shows that Pt/FAU-C enhances the formation of smaller Pt clusters compared to Pt/W-C and Pt/ANA-C which exhibit a homogeneous Pt dispersion. XRD results indicate that Pt/zeolite-C shows different intensity of Pt crystallinity. XPS analysis indicated the presence of Pt0 and Pt2+ on the electrocatalysts. The content of Pt0 was influenced by the nature of the support evaluated. The Pt/FAU-C electrocatalyst exhibited higher electrochemical activity for MOR showing the lowest onset potentials and the highest oxidation current of methanol compared to Pt/W-C, Pt/ANA-C and Pt/C. It was associated with the intrinsic properties of substrates that modify the size, dispersion, crystallinity, electronic density and hydrogen ion spillover for MOR.