TiO₂/C composite as a support for Pd-nanoparticles toward the electrocatalytic oxidation of methanol in alkaline media

The electro-oxidation of methanol was studied in alkaline solution on Pd nanoparticles supported on carbon black (XC-72R, C) and TiO₂/C composite. The materials were prepared via organic colloid route at 170 C with 5 wt% of Pd. X-ray diffraction (XRD), PdO monolayer reduction (PdO_red) and CO-stripping was employed to characterize both structure and electrochemical properties. According to this, the lattice parameter decreases from 0.3991 to 0.3905 nm due to a possible formation of Pd-Ti alloy. This modification is linked with the electrochemical active surface area (ECSA) decreasing from 22 to 18 m² g^-1. On the other hand, studies as a function of temperature and alcohol concentration indicated that the current for methanol electro-oxidation is higher and more stable at Pd/TiO₂-C, with E_a = 44.042 kJ mol^-1. Then, it is highly possible that at Pd/TiO₂-C, the OH^-/OH _ads couple is adsorbed at the TiO₂ sites, increasing the kinetic of methanol oxidation reaction at the catalyst surface.