Preparation Of Cu,Ce,B Doped TiO₂ Nanotubes And Research On Their Photocatalytic Denitration Performance

As one of the major air pollutants,nitrogen oxides leads to a series of environment problems such as photochemical smog,acid rain,greenhouse effect and haze weather and so on,which are harmful to the ecosystem and humanity.As an environmentally friendly and low cost method for removal of nitrogen oxides,photocatalyst has attracted an increasing attention.Among various kinds of the photocatalysts,TiO2 nanotube with great surface area,strong adsorption capacity and high conversion efficiency of photoelectric has now been applied to photocatalysis,sensing and solar cellother fields.However,the efficiency of photocatalytic reactions is limited by the wide band gap and by the high recombination rate of photoinduced electron-hole pairs of TiO2.In order to improve the photocatalytic performance,a series of of Cu,Ce,B sing-doped and co-doped TiO₂ nanotubes were prepared in the research.In this paper,TiO2 nanotubes?TNTs?were synthesized using the TiO2 nano-particle as raw material and CTAB as a surfactant by hydrothermal method,and the effects of hydrothermal reaction time,picking and calcinations time on the nantobutes forming were further investigated.The study shows TNTs were obtained by the sheet from powder,then rolled up into tubes as the reaction time going on,the ratio of structural transformation from nanopowder to nanotube is nearly 100%when reaction time is 29h;the Ti O2 nanootubes have a better dispersibility and the tube wall were smooth after picking;The TEM,XRD and TG-DSC shows that nanotubes have reached the best morphology under 400^oC calcining;Simultaneously,the paper studys the effect of the crystalline phase and morphology of TiO2,the amount of photocatalytic catalyst,oxygen conentent,relative humidity?RH?,nitrogen oxides concentration and flow rate on the photocatalytic denitration,and the optimal formula of experimental conditions were selected:the antase TNTs,the amount of photocatalytic catalyst is 0.4g,oxygen conentent is 20%,relative humidity?RH?is 65%,nitrogen oxides concentration is 100ppm and flow rate is 100mL/min.To address the wide band gap and the high recombination rate of photoinduced electron-hole pairs of TiO2,Cu,Ce,B single-doped and co-doped TNTs were successfully prepared by hydrothermal method.The phase,morphology,size and structure of as-prepared samples were characterized by XRD,TEM and EDS,which indicated that Cu,Ce,B were implanted into the lattice of TiO2;While the photocatalytic performance of as-prepared samples were evaluated by UV-Vis,PL,XPS and MS,which proved that exists the optimal single-dopded ratio of Cu,Ce,B and discussed the modification mechanism of doping:doping of cerium oxides(Ce⁴⁺/Ce³⁺)and boron into the lattice of TiO₂ will introduce impurity energy levels in the conduction band?CB?and the valance band?VB?,which further narrows the band-gap.Meanwhile,Copper and cerium oxides can trap photo generated electrons and prohibit the recombination of electron-hole pairs.The possible mechanism for photocatalytic denitration reaction was proposed through FT-IR spectrum of Cu,Ce,B tri-doped TNTs before and after reaction.