Design and preparation of highly active carbon nanotube-supported sulfated TiO2 and platinum catalysts for methanol electrooxidation

A novel electrocatalyst structure of carbon nanotube-supported sulfated TiO2 and Pt (Pt–S–TiO2/CNT) is reported. The Pt–S–TiO2/CNT catalysts are prepared by a combination of improved sol–gel and ethylene glycol reduction methods. Transmission electron microscopy and X-ray diffraction show that the sulfated TiO2 is amorphous and is coated uniformly on the surface of the CNTs. Pt nanoparticles of about 3.6 nm in size are homogenously dispersed on the sulfated TiO2 surface. Fourier transform infrared spectroscopy analysis proves that the CNT surfaces are modified with sulfated TiO2 and a high concentration of SOx, and adsorbed OH species exist on the surface of the sulfated TiO2. Electrochemical studies are carried out using chronoamperometry, cyclic voltammetry, CO stripping voltammetry and impedance spectroscopy. The results indicate that Pt–S–TiO2/CNT catalysts have much higher catalytic activity and CO tolerance for methanol electrooxidation than Pt/TiO2/CNTs, Pt/CNTs and commercial Pt/C.