Study On Preparation And Electrochemical Performance Of Pt/TiO₂ Catalysts

Direct methanol fuel cell?DMFC?is considered to be one of the small mobile power supply,and methanol has the advantages of the abundant sources,low price,no pollution to environment,no C-C bond and the higher electrochemical activity comparing to other power.But methanol anodic oxidation reaction is autointoxication,low kinetics and serious polarization,so producing new effective anode catalysts that can improve methanol reaction activity and resist to CO poisoning is the problem that must be solved continuously.This dissertation focused on about the synthesis of metal oxide TiO₂ nanomaterials as carrier modified Pt-based catalyst.The research contents are as follows:Part ?.TiO₂ nanofibers with different crystalline phases were prepared by electrospinning technique and calcined at 400-700 ?;Pt/TiO₂ catalysts were fabricated by reduction impregnation method using them as carriers.Studying on catalytic activity and stability of catalysts,and exploring the influence of calcination temperature on TiO₂ phase and electrocatalytic performance in an acidic solution.Research results show,with the increase of temperature,the content of Rutile in TiO₂ nanofibers is increasing.TiO₂ nanofiber has the value of Rutile content is 2.67 wt.%and the smallest grain size of Pt nanoparticles loading on the surface of nanofiber and the largest active area at 550 ?.Catalyst using it as the carrier has the best catalytic activity,stability and anti-poisoning ability in methanol oxidation reaction.Part ?.TiO₂ aerogel was prepared by sol-gel and organic solvent sublimation drying?OSSD?method,and Pt/TiO₂ aerogel catalyst was fabricated by reduction impregnation method;the Pt/P25 catalyst was prepared with the same mass fraction of Pt nanoparticles using the commercial TiO₂ nanosphere?P25?as the carrier.Electrochemical tests show that Pt/TiO₂ aerogel catalyst exhibits the highest catalytic activity,stability and anti-poisoning ability in methanol oxidation reaction.Part ?.TiO₂-CeO₂ nanofibers,which were prepared by sol-gel method and electrospinning technique with different content of CeO₂,can form Pt/TiO₂-CeO₂ catalysts fabricating by loading Pt,then the effects of different carriers on electrocatalytic performance were discussed.Charactering the chemical composition,crystalline phase and microscopic surface state,and testing electrocatalytic oxidation activity of methanol of electrode materials.The results indicate that Pt/TiO₂-CeO₂ catalyst has the best catalytic activity,stability and anti-poisoning ability in methanol oxidation reaction when w?CeO₂?/w?TiO₂?is 10%.