Preparation And Electrochemical Properties Of Pt-TiO₂/Ti Composite Electrode

TiO₂/Ti is an electrode with high corrosion resistance. And nano Pt is a catalyst with high catalytic activity, whose size, shape and distribution infect its properties. Therefore, in order to prepare a composite electrode with high activity, the special nano Pt-TiO₂/Ti composite structure was prepared by anodic oxidation- electrodeposition with ultrasonics, and characterized properties in this work.Firstly, TiO₂ naotubes were gained on the substrate by constant voltage anodic oxidation with the hydrofluoric acid as electrolyte. Then nano-Pt coating was deposited on the TiO₂ naotubes by constant current electrodecomposition with the chloroplatinic acid as electrolyte .The morphology and the structure of TiO₂ naotubes and nano-Pt coating were observed and analysed respectively with the aid of FESEM and XRD. The effects of the anodization parameters on the morphology and crystal structure of TiO₂ nanotubes and the electrodeposition parameters on the morphology and crystal structure of nano Pt were respectively investigated. It was indicated that the tidiest TiO₂ nanotubes were obtained on the pure titanium at 20V voltage and 25 minutes oxidation time; when the electrolyte was low in concentration or the depositing current was small, the as-deposited Pt appeared mostly in particles, and tended to be changed in flower structures or plexi structures with the increasing of the current or the deposition time. Meanwhile, the composite electrode with the upper layer of Pt and the lower structure of TiO₂ nanotubes was prepared by depositing with ultrasonicassisted.Moreover, Pt-TiO₂/Ti composite structure was characterized respectively by CV and polarization curve in the 0.5mol/L sulfuric acid and 0.5mol/L methanol mixed with sulfuric acid. The results showed that the electrocatalytic activitics and the stability of the composite electrode for the methanol oxidation were better than those of Pt electrode and Pt/Ti electrode. And the electrode possessed the best properties prepared at the 5mA/cm2 current density in the 1.0g/L electrolyte for 1 minute.