The Experimental Research On Modification Of TiO₂ Denitration

In this paper,we finally used sol-gel hydrothermal method to prepare different metal doping modification of TiO₂ catalyst after comparing with the difference between the sol-gel method,column brace soil preparation method and sol-gel hydrothermal prepration of TiO₂ catalyst.Its calcination temperature can be reduced 300 ℃ comparing with the sol-gel method,which is greatly reduced energy consumption.With NO as the research object of different modified TiO₂ catalyst has carried on the visible light catalytic experiment and selective catalytic reduction（SCR）to explore the preparation conditions and reaction conditions on the modified TiO₂ catalyst removal of NO effect,and to explore its continuous use,reaction kinetics and reaction mechanism,etc.The experimental results show that with cerium nitrate as the source of Ce（doped molar ratio,1%）,nitric acid cobalt for Co source（doped molar ratio,5%）,under the condition of water fluid temperature is 160℃water reactioning after 24 h,and then calcined under 200℃ we can prerare the best performance Ce（1%）-Co（5%）-TiO₂ catalyst.The visible light efficiency of this catalyst for concentration of 672mg/m3 NO can up to 92.69%,and for concentration to 3424 mg/m3 its visible light catalytic efficiency can still reach 71.86% at the room temperature.Using the catalyst for the selective catalytic removal of NO experiment,it found that when the concentration of NO was 600 mg/m3,the removal efficiency of this catlyst can reach 98.99%.What’s more,when increasing the concentration of NO to 2047 mg/m3,its denitration efficiency can still reached 83.74%,that is to say the prepard-catalyst has a good performance.In addition,the catalyst was applied to the experiment of the resistance of SO₂,and it found that in the resistance of SO₂,the efficiency of the commercial catalysts was reduced about 10%,but the Ce（1%）-Co（5%）-TiO₂ catalyst was about 5%,which proved the Ce（1%）-Co（5%）-TiO₂ catalyst also has strong ability to resist poisoning.For the modified TiO₂ catalyst to BET,XRD,SEM,EDS,UV-Vis,NH3,TPD,XPS characterization analysis test,the results show that the Ce,Co element doping TiO₂ catalyst increased its specific surface,reduced its grain size and maked the crystal degree of crystallization more perfect.Besides,it promotes the catalyst for the NO adsorption,so as to make the catalyst of catalytic oxidation of NO increased.At the same time,the element doping makes the particles forbidden band width is reduced,catalyst redshift,widened the scope of its response to visible light,make its visible light catalytic performance improvement.The particles of forbidden band width is reduced,the catalyst formed red-shift,so that its response scope of the visible light was widened.In addition,the surface acidity and the acid of the catalyst were improved,which made its adsorption performance of NH3 a further enhance,the catalytic oxidation of NO₂ reduction efficiency,which finally showed the modified TiO₂ catalyst for NO removal effect.