1. “Self-cleaning coatings of doped TiO 2 nanostructured powders for applications in construction industry” I. Deligkiozi *, P. Karlsson, T. Kosanovic, M. Pappa, P.M. Sakas, A. Zoikis–Karathanasis Center for Research and Technology Hellas, CERTH/IRETETH, Volos, Greece Deligkiozi Ioanna, Chem. Engineer, ΝΤUA, B.Sc., M.Sc., Ph.D. _________________________________________

2. Outline of the presentation 2  Introduction to the scope  Theoretical aspects  Scientific background & targets  Experimental results  Concluding remarks EinB2014 - 3 rd International Conference “ENERGY in BUILDINGS 2014”

3. Early adopters Rapid advancements Mass market Basic research Applied research 1970 1990 2000 2006 2010 2020 Low High Nanotechnology & building materials? 3 1 nm = billionth of a meter 10 -9 m CNTs 1 nm CNTs 1 nm Hair 100 μm Hair 100 μm House 100 m House 100 m € 1000 billion (National Science Foundation) EinB2014 - 3 rd International Conference “ENERGY in BUILDINGS 2014” Construction industry is a $1 trillion industry/year Improves the functional properties NEW advanced materials

4. Primarily used as white pigment TiO 2 – an Ideal Photocatalyst 4 EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

5. Shift the optical gap toward the visible range Dopants Metallic dopantsAg Non-metal dopantsN, S and C Basic idea 5 TiO 2 (anatase) E g =3.2eV ex  387nm E t  5% EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

6. h + + - - NanoTiO 2 Scope & Photo-degradation High photo-chemical corrosive resistance, Strong oxidizing power, Photocatalysis takes place at ambient temperature, Atmospheric oxygen is used for the reaction, High Surface area, Small Crystalline Size, Anatase form of TiO 2, High crystallinity, Porous structure, Cheap and can be reused 6  Sol-Gel synthesis  Doping of TiO 2 size and surface modification by metal and non – metal elements.  Reducing the particle size in the nano meter scale  Absorption in the visible range can be improved by  Anatase phase EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

7. V.B. C.B. hv (UV light) e-e- O2O2 O2-O2- Doped- TiO 2 -OH Organic Pollutant Degradation -OH 7 Energy Level Eg Photo-degradation mechanism e-e- h+h+ Reduction Oxidation < 2.3 eV (Vis light) Efficiency of photocatalysis depends on how well one can prevent this charge recombination ~3.2ev (UV light) Electron-Hole recombination is on the order of < 30ps, hence efficiency is low (< 5%). EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014” hv (Vis light)

8. Application of Self-Cleaning coatings Nanotechnology materials & coatings for retrofitting Self - Cleaning Glasses Self – Cleaning & Antibacterial coatings Self – Cleaning Concrete Self – Cleaning paints 8 EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

9. Sol-Gel Synthesis --- Different parameters -- 2 Different experimental processes -- 2 Different non metal doping sources (Urea, Thiourea) -- 1 Different metal doping source Characterization -- XRD -- SEM -- Band Gap -- Z-sizer Photo - catalysis -- Investigate loadings -- Methylene Blue (MB) -- Methyl orange (MO) 9 EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

10.  Synthesis  Characterization  Photo - Catalysis 10 EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

11. Sol-Gel Synthesis steps 11 EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

12. Ti precursor Ti precursor TBOT Precipitation agent i-PrOH BuOH Urea Thiourea Calcination 400 o C 500 o C 600 o C 700 o C 800 o C Non-Metal dopants Non-Metal dopants Experimental design Metal dopants Metal dopants Silver Nitrate 12 EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

13. Hydrolysis TBOT aq. HNO 3 vigorous stirring 3h r.t. Precipitation n-BuOH dropwise vigorous stirring overnight r.t Crystallization S, N @ Ag Doped TiO 2 10g of Urea/Thiourea @ 0.13, 0.26 & 0.56g of Ag stirring and ultra sound Condensation 400 o C Purification H 2 SO 4 1M washing with water pH=6 Sol-gel synthesis of Co-doped TiO 2 Calcination at 400, 500, 600, 700 and 800 o C 13 EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

14.  Synthesis  Characterization  Photo - Catalysis 14 EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

15. Kubelka-Munk function, F(R) Extrapolation of this Tauc linear regime line to the photon energy axis yields the band gap Band Gap measurements 15 EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

16. Doping amount Thiourea (S,N) 1g3.065 5g3.04 10g2.3 & 3.15 15g2.99 Band gaps for [S,N] doped TiO 2 16. 1g Thiourea 5g Thiourea 10g Thiourea 15g Thiourea EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

17. Band gaps for [S,N] & [Ag] doped TiO 2 17 Energy Band Gap 2.2 eV Energy Band Gap 2.2 eV EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

18. XRD powder diffraction 18 Spurr-Myers equation Anatase to Rutile Transformation Scherrer equation Grain size evaluation EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

19. Sol-gel hydrolysis & XRD 19 EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

20. 20 XRD [S,N] doping vs Temparature 88 % [A] / 12% [R] 100 % [R] 20 X-ray diffraction patterns of thiourea doped TiO 2 nano-powder calcinated at 400, 500, 600, 700 and 800 o C for 2 h EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

21. SEM measurements 21 EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

22. DLS measurements Dynamic Light Scattering (DLS) was used in order to define the size distribution of sample powders. DopantTreatment Mean Intensity Peak 0.3-100.0nm100-999nm1μm-10μm 10g Thiourea 400  C 220.21126.01420.05177.0 10g Urea 400  C/filtered 24.3653.6670.42 10g Tiourea 400  C 70.30 255.0 10g Urea 0.13g Ag 400  C 220.2 10g Urea, 0.13g Ag 500  C 5.9950.75255.0 10g TU, 0.13g Ag 400  C/filtered 78.77 22 EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

23.  Synthesis  Characterization  Photo - Catalysis 23 EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

24. 24 Homemade Photocatalytic Reactor 24 Degradation of MO & MB: TiO 2 = 50 mg, C=5.3 mg/L, Volume=0.25 L, Temperature = 28 o C, Light sourceWavelength output 4 daylight lamps, 18W 380-790 nm, Daylight Sylvania, F18/54-765-T8 1050 Lumen EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

25. 25 Evaluation of Photocatalytic Degradation EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

26. Photocatalysis in MO 26 Comparison between UV-Vis and Vis irradiation on the same sample Comparison between N doped and N, Ag doped samples. EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

27. Photocatalysis in MO 27 Comparison among samples calcined at 500  C and having all different dopants (N, S and Ag). Assessment on the Ag doping amount EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

28. Diminished radiation conditions 28  Simulation of indoor conditions, cloudy day, shades, etc  Lamps: 4 OSRAM F18W/54-765  Membrane to cut off UV by 99%, IR by up to 92% and visible band by 10%  Total solar energy rejection of 49%  Irradiation time: 17 hours Photocatalytic activity of thiourea and silver modified titania under diminished radiation conditions (UV and IR cut off as well as visible irradiance diminishment.) EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

29. Concluding Remarks 29 Nitrogen, sulfur and silver doped Titania nanoparticles were synthesized using sol- gel technique 10g Thiourea [S, N] & 0.13g [Ag] Reduction of the Band Gap < 2.3 Dominantly anatase phase From the degradation of MO & MB dye experiments doping effect was observed in the doped Titania photocatalyst Efforts are underway to formulate the paintings systems EinB2014 - 3rd International Conference “ENERGY in BUILDINGS 2014”

30. 30 Deligkiozi Ioanna, Chem. Engineer, ΝΤUA, B.Sc., M.Sc., Ph.D. deligioanna@gmail.com “Self-cleaning coatings of doped TiO 2 nanostructured powders for applications in construction industry” I. Deligkiozi *, P. Karlsson, T. Kosanovic, M. Pappa, P.M. Sakas, A. Zoikis–Karathanasis 1 Center for Research and Technology Hellas, CERTH/IRETETH, Volos, Greece