The nanoTiO₂-CNT-PtNi complex catalysts were prepared by the direct hydrolysis of electrosynthetic precursor Ti(OEt)₄ and electrochemical scan electrodepositing method. The results of XRD and SEM show that the PtNi nanoparticle of average size 8 nm was dispersed uniformly on nanoTiO₂-CNT complex film surface. The electrocatalytic activity of the nanoTiO₂-CNT-PtNi complex catalysts was investigated by cyclic voltammetry and chronopotentiogram. The results indicated that the nanoTiO₂-CNT-PtNi complex catalysts with Pt loading of 0.32 mg/cm² exhibited high electrochemically active surface area of 90 m²/g and very high electrocatalytic activity and stability for electro-oxidation of methanol. The oxidation peak potential of methanol was 0.67 and 0.44 V at room temperature in atmosphere pressure, respectively, and shifted to 0.64 and 0.30 V at 60 ℃ and the oxidation peak current of methanol was 1.38 A/cm². The high electrocatalytic activity and good stability can be attributed to the synergistic catalytic effect of nanocomposite, which leads to the weak adsorption of CO on complex nanostructure catalysts, avoiding poisoning of the catalysts.

Key words: direct methanol fuel cell, anode catalyst, nanocrystalline TiO₂, carbon nanometer tube, PtNi alloy particle, complex catalyst, electro-oxidation of methanol, scan electrodepositing