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

Jasim, A. - Presenter, University of Missouri
Xing, Y., University of Missouri
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/ IrOx-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/IrOx-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 TixO2-x where hydroxyl ligand is formed supplying protons to Pt-COads. 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.