The Catalytic Performance Of Hydrogenated Pt/TiO₂?B? Nanobelts Catalysts For Catalytic Oxidation Of CO

With the rapid development of economy and society,fossil energy?water,oil,natural gas?has been consumed in large quantities,which has caused a series of environmental problems,and has affected the daily life of human beings and the sustainable development of society.Carbon monoxide produced by incomplete combustion of fossil fuels is very harmful to human life.The effective means to eliminate the low concentration of CO in automobile exhaust or factory waste gas is catalytic oxidation.In this work,TiO₂ nanobelts were prepared by hydrothermal method.Its crystal form is TiO₂?B?.After a certain amount of chloroplatinic acid impregnated,the Pt/TiO₂ catalysts were obtained prereduced by pure hydrogen at different temperatures.The catalytic performance of Pt/TiO₂ catalyst for CO oxidation was evaluated.All the catalysts showed good activity and water resistance.Our findings show that through hydrogen spillover from Pt to TiO₂,surface-engineered defects of oxygen vacancies are“constructed”on the conventional“catalytic inert”TiO₂support during hydrogenation,thus generating active surface adsorbed oxygen species.With the increase of the reduction temperatures,the TiO₂?B?phase gradually transforms to the anatase phase,which takes place from bulk to surface of TiO₂,and eventually completes at 700°C.Compared with the anatase phase,the oxygen vacancies are more easily formed on the TiO₂?B?phase,and the latter has the much stronger interactions with Pt,as well.As the reduction temperature increases,the metal-support interaction between Pt and TiO₂?B?is strengthened.Meanwhile,we simultaneously observe the increase of the dispersion of Pt,the proportion of Pt⁰ and the adsorbed oxygen species on the surface.Our findings reveal that upon the hydrogenated Pt/TiO₂ catalysts the surface adsorbed oxygen and Pt⁰ are active species for catalytic oxidation of CO.Among the hydrogenated catalysts,H-600 shows the highest catalytic activity because it has the largest amount of the active Pt⁰ sites and surface adsorbed oxygen species.In addition,it shows the high water vapor resistance.In order to enhance the performance of catalysts,basing on the above research,different amounts of alkali metal promotor potassium was added.After that,the K-Pt/TiO₂ catalysts were hydrogenated and used for catalytic oxidation of CO.The catalyst with a potassium content of 0.3 wt%exhibited the best catalytic performance among all the catalysts.The results of X-ray photoelectron spectroscopy and oxygen storage complete capacity demonstrated that the alkali metal promotor K promoted the formation of oxygen vacancies and increased the amount of active oxygen species.A proper amount of potassium can lead to the increase of dispersion of Pt,and it can enhance the performance for catalytic oxidation of CO.