(404f) Ptir/IrOx on Fluffy TiO2 /CNTs As a Catalyst for Methanol Oxidation

A new strategy for Iridium decoration with Pt nanoparticles by loading them onto a fluffy 10-nm titanium dioxide (TiO₂) surface via aqueous solution reduction method with 20 wt.% of Pt and Ir combined. As a prepared catalyst, denoted PtIr/ IrO_x-C-TiO₂/CNTs, was used for methanol electro-oxidation (MOR). The purpose is to load those metals onto a stable, conductive, and anticorrosion support of C-TiO₂/CNTs. It was found that in this study the TiO₂ coating plays a crucial role by offering a high geometrical surface area that makes optimum support to host the metal nanoparticles with small nanoparticle size. Having those metals deposited onto doped TiO₂ with small size particles has increased the active site population toward methanol molecules and enhanced the catalyst activity. Based on electrochemical results of MOR, PtIr/IrO_x-C-TiO₂/CNTs has shown a significant improvement in the anodic to cathodic current ratio with a 5.6-fold and a negative shift in onset by 120 mV relative to E-TEK (Pt/C). Furthermore, both metals shared electrons in back donation with the oxide support as a positive shift in their binding energy as revealed by XPS. We may attribute the high forward/backward current ratio and high current after one hour to hydrated iridium oxide phase incorporated on reduced Ti_xO_2-x where hydroxyl ligand is formed supplying protons to Pt-CO_ads. All other characterizations and the analyses such as X-ray diffraction (XRD), transmission electron microscopy (TEM), electron spectrum (EELS) were carried out to further understand the prepared catalyst.