Poly (p-phenylendiamine/TiO₂) nanocomposite promoted Pt/C catalyst for methanol and ethanol electrooxidation in alkaline medium

In the present study, poly (p-phenylendiamine/titanium dioxide) (PpPDA/TiO₂) nanocomposites (NCs) were prepared by in situ polymerization of p-phenylenediamine monomer with of different TiO₂ loading. A facile method was developed to promote the electrocatalytic activity of commercial Pt/C catalyst by ultrasonically mixing Pt/C catalyst and PpPDA/TiO₂ NCs. The PpPDA/TiO₂ NC, Pt/C catalyst and composite catalyst of Pt/C + PpPDA/TiO₂ were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The surface morphology of Pt/C is significantly influenced by the presence of PpPDA/TiO₂ NC as confirmed by SEM observations. Cyclic voltammetry (CV) measurements showed that the PpPDA/TiO₂ NC leads to a significant improvement in the activity and stability of Pt/C for alcohol oxidation especially for ethanol oxidation in alkaline medium. For Pt/C + PpPDA/TiO₂, the onset potentials shift to negative values by 30 and 160 mV compared to the onset potentials of Pt/C for methanol and ethanol oxidation, respectively. Chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) results also confirmed that this composite catalyst has superior catalytic performance towards ethanol oxidation compared to the pure Pt/C catalyst.