Platinum Nanoparticles Synthesis Supported in Mesoporous Silica and Its Effect in MCM-41 Lattice

Platinum nanoparticles were incorporated in MCM-41 mesoporous support. Two different ways to incorporate metallic nanoparticles were evaluated (i) Pt wetness impregnation in MCM-41 previously synthesized and (ii) Pt incorporated in situ during MCM-41 synthesis in alkaline (iia) and acid (iib) media. Synthesis conditions influence was studied by X-Ray diffraction, nitrogen adsorption analysis and electron microscopy. High surface areas (up to 900 m2/g) were obtained in all methods. However, high Pt loading were observed only in wetness impregnation and in situ incorporation in alkaline media methods. Additionally, composites Pt/MCM-41-black carbon were prepared and their electrocatalytic activity and electrical bulk resistance were studied by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), respectively. An interesting behaviour was observed in the samples where the platinum was in situ incorporated; the samples show structural and textural properties modifications compared to raw MCM-41.Hydrogen oxidation reaction by CV was observed in high Pt loading samples. On the other hands, EIS results indicate that Pt/MCM-41 materials synthesized by in situ incorporation methods have lower electrical bulk resistance than the samples prepared by wetness impregnation method.