Avci, Nursen

Cimieri, Iolanda

Poelman, Dirk

Poelman, Hilde

English

Ghent University Academic Bibliography

IntroductionPhotocatalysis : removal of small amounts of VOCs from contaminated indoor atmosphere.TiO2 is close to being an ideal photocatalyst: non toxic, physico-chemically stable, self-cleaning and highly selective.Sol-gel method is one of the most versatile methods to obtain TiO2: control of stoichiometry, synthesis in mild and ambient atmospheric conditions,high purity, porosity and homogeneity.Aim of this study: synthesize stable TiO2 sols by the sol-gel method, preparation of thin films, evaluate the influence of a stabilizing agent (diethyleneglycol) and the effect of V, Nb and Ta doping on the photocatalytic activity of the films.Conclusions • DEG addition does not improve the photocatalytic activity of the films.• The visible response is larger for the 10wt.% doped film than for the 20wt.% one, in casethe alkoxide is used as dopant precursor.• The doping process was successful and the dopants were inserted into the TiO2 unit cell asconfirmed by XRD analysis.• Among the developed catalyst, the 10 wt.% Ta doped titania shows the highestphotocatalytic activity and this is attributed to a similar ionic radius between Ta and Ti.Sol-gel preparation of pure and doped TiO2 films for the photocatalytic oxidation of ethanol in airIolanda Cimieri 1 , Hilde Poelman 2 , Nursen Avci 1 , Dirk Poelman 11LumiLab, Department of Solid State Sciences, Ghent University, Belgium2Department of Chemical Engineering, Ghent University, Belgium References[1] H. Tomaszewski et al.,  Int. J. Photoenergy 8 (2007) 1-5Contact: iolanda.cimieri@ugent.beDouble coated film, pre-heated at 100C for 8h and calcinedat 450 C for 2h: highly active if compared with TiO2 filmsprepared from Degussa P25.Photocatalytic measurements: carried out in a stainless steel batch reactor, in acontrolled Ar/O2 atmosphere, by means of an atmospheric gas analyser containing amass spectrometer.Choice of the best film preparation conditions:• Number of layers (single, double and triplecoating)• Pre-heat treatment at  100 C for 8h• Different calcination temperature(450, 500 or 550 C)Doping effectAim: obtain a higher photoresponse in the visible region.Experiments: series of 10 and 20wt.% vanadium, niobium and tantalum-dopedTiO2 catalysts .Precursor used: dopant alkoxide; for V doping two different precursors: alkoxideand V2O5 .Stabilizer effectAddition of DEG: stabilization of the sol and improvement of the adhesionfilm/glass [1].DEG experiments performed:Sample Number of layersPre-heat treatmentat 100⁰CCalcinationtemperature(⁰C)Photocatalyticactivity  3σ(ppm/min)A 1 yes 450 3.090.23B 2 yes 450 3.240.28C 3 yes 450 1.760.15D 1 no 450 1.870.30E 2 yes 500 0.600.05F 2 yes 550 0.490.06P25 4   3.640.03• Different amounts of additive (molar ratios 1, 2.5, 5 and 10) • Number of layers (single and double coating)

Sol-gel preparation of pure and doped TiO2 films for the photocatalytic oxidation of ethanol in air

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Sol-gel preparation of pure and doped TiO2 films for the photocatalytic oxidation of ethanol in air

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Ghent University Academic Bibliography