Nanoparticles of Pt/H_xMoO₃ electrodeposited in poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) as the electrocatalyst for methanol oxidation

Nanoparticles of platinum and hydrous molybdenum oxide (Pt/H_xMoO₃) were successfully electrodeposited onto poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) (PEDOT-PSS) film by chronocoulometry (0.2 C). Various loadings of Pt/H_xMoO₃ particles onto the PEDOT-PSS electrode were achieved using the co-deposition technique. The existence of Pt/H_xMoO₃ particles was determined through characterization by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis. XPS results revealed that deposited Pt and molybdenum were metallic Pt and H_xMoO₃, respectively. XRD analysis showed a decrease of Pt crystalline facets for the incorporation of H_xMoO₃ into PEDOT-PSS-Pt, indicating a strong interaction between Pt and H_xMoO₃. Scanning electron microscopy (SEM) results revealed a uniform dispersion of Pt/H_xMoO₃ particles, with the particle size of 70-90 nm, in the PEDOT-PSS matrix. The cyclic voltammetry study and chronopotentiometry measurements demonstrated that the PEDOT-PSS-Pt/H_xMoO₃ electrode had superior electrocatalytic activity of methanol oxidation with less CO poisoning. The presence of amorphous H_xMoO₃ particles on the Pt surface minimized CO poisoning of methanol oxidation.