UNIVERSITY OF PATRAS FORTH
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UNIVERSITY OF PATRAS D. Kouzoudis http://www.icmmm.net/ ICMMM2011 , 8-10 Dec 2011, Beijing Zhengzhou, China 2012.9.21-23 FORTH-ICEHT UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Zeolite thin films as new materials for chemically active layers in magneto-elastic sensors D. Kouzoudisa, V. Nikolakisb, Th. Baimposb a Editor-in-chief, Sensor Letters University of Patras, Greece b FORTH, Patra Greece ICMMM2011 , 8-10 Dec 2011, Zhengzhou, China http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Zeolite thin films as new materials for chemically active layers in magneto-elastic sensors VOC Outline • Zeolite films – excellent active sensing layers Review Zeolite film • Magnetoelastic (ME) resonance sensors ME sensor • Volatile Organic Compounds (VOC) • Detection of VOCs with Zeolite/ME sensors ICMMM2011 , 8-10 Dec 2011, Zhengzhou, China http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Zeolites (Review on Sensing Applications) ICMMM2011 , 8-10 Dec 2011, Zhengzhou, China http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Zeolites • Inorganic, crystalline, aluminosilicate materials • Chemically and thermally stable • Industry: Excellent catalysts, molecular sieves, ion- exchangers, water softeners •170 different types, about 17 of them commercial interest ICMMM2011 , 8-10 Dec 2011, Zhengzhou, China http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Zeolites + + Na+ = • Consist of interconnected SiO2 and AlO2 tetrahedra & Cations+ • Tetrahedra form 3D frameworks with linked channels down to molecular level • High porosity, pores fixed down to nm sizes -> gas sensing • Exceptionally high specific-surface-area 400 m2/gr (two large apartments in one gram !!!) http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis Zeolite Building blocks FORTH-ICEHT SiO2 tetrahedra Chemical formula SiO2? Tetrahedra connected at corners Each Oxygen is shared by 2 tetrahedra All corners are connected 4 × ½ = 2 O atoms → Si O Si O O O Si Si Si Schematically, oxygen are shown as straight lines (bonds) and Si at the corners All corners are connected → 4 lines from each Si http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Zeolite - Silicalite (MFI) 1-D channels Si Si O All bonds are homopolar → no polarity in the crystal → Extremely hydrophobic http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Zeolite - Silicalite (MFI) Simplified planar view (SiO2) http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Broken Bond Two Different Building blocks SiO2 AlO2 The Al cannot form heteropolar bond with one O => Local electronegativity => Extra cation Na+, Ca++ trapped => Polarity in the crystal Na+ http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Zeolite LTA, Si/Al = 1 Simplified planar view + Na http://www.icmmm.net/ Na+ [(SiO2) (AlO2)- ]. zH 2O 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Zeolite LTA, Si/Al = 1 + + + Simplified planar view + + + + http://www.icmmm.net/ Na+ [(SiO2) (AlO2)- ]. zH 2O 2012.9.21-23 Beijing Na UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Zeolite LTA, Si/Al = 1 + LTA + Cations cause polarity → attract polar molecules (water, CO2) http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Zeolite FAU, Si/Al ≠1 FAU + + + (Na+, Ca++) + Xm+y/m [(SiO2)x (AlO2)-yhttp://www.icmmm.net/ ]. zH2O 2012.9.21-23 Beijing UNIVERSITY OF PATRAS LTA MFI FAU D. Kouzoudis Si 50% - Al 50% Cations Na, Ca Polar 3-D straight channels Si 100% non-polar Hydrophobic 1-D channels Si x% - Al y% Cations Na, Ca Polar 3-D entangled channels http://www.icmmm.net/ 2012.9.21-23 Beijing FORTH-ICEHT Ring 8 Ring 10 Ring 12 UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Useful Zeolite properties for sensing • Trap selectively gas molecules of the right size • Trap selectively gas molecules of the right shape • Trap selectively gas molecules of the right polarity • Highly polar materials, ion conductors and ion exchangers • Al+3 acidic site: catalyze a number of chemical reactions • Room temperature operation • High specific surface http://www.icmmm.net/ 2012.9.21-23 Beijing Molecular Sieving for octane-isomers LTA UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Main Disadvantages: • Polar Zeolites adsorb humidity, need initial degassing • Slow Diffusion (gas out) http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Basically there are 5 different ways on how to use Zeolites for Sensing Applications: Mass Load Film Properties Filter Guest/Host Composite http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis Mass Load: Selective adsorption of certain molecules → Microbalance senses mass load zeolite microbalance QCM, SAW, Magneto-elastic, Microcantilever http://www.icmmm.net/ 2012.9.21-23 Beijing FORTH-ICEHT UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Film: Selective adsorption of certain molecules → Redox interactions with cations → Change of film property zeolite V Impedance Spectroscopy Resistive Sensors Capacitive Optical http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis Filter : Selective adsorption of certain molecules → make it to the sensitive layer (+ catalysis ) zeolite sens. layer sensor MOS silicon sensors http://www.icmmm.net/ 2012.9.21-23 Beijing FORTH-ICEHT UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Guest/Host: Certain molecular complexes pinned at zeolite sites act as sensing centers such as fluorophores, dyes complex Fluorescent Optical sensors zeolite http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Composite: Zeolite placed inside a matrix in order to improve its sensing properties zeolite matrix http://www.icmmm.net/ 2012.9.21-23 Beijing Conductive Polymer sensors UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Type Mass load Sensor QCM SAW microcantilever Sensed Gas NO, SO2, DMMPS. acetone pentane, hexane, H2O, NH3 freon Film proton conductive zeolites Na+ ion conducting zeolites Ru(II) complex/zeolite methylene blue/zeolite LiCl/zeolites magnetoelastic optical fiber surface plasmon resonance NH3 hydrocarbons methanol, 2-propanol and 3-pentanol Guest/host Filter Composites polyaniline/zeolite zirconia/zeolite platinum/Y-zeolites SrTi1-xFexO3/zeolite TiO2/zeolite SnO2/zeolite O2, H2O O2, CO, CO2, organics, butylamine CO NO C4H10, CO and H2 hydrocarbons alkanes hydrocarbons methane, propane, and ethanol Xiaowen Xu, Jing Wang, and Yingcai Long, Sensors 2006, 6, 1751-1764 http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Zeolite based gas sensors Detection of Sensor type Zeolit e Detection principle Freon-12 PZT m-balance MFI Adsorption mass load Acetone QCM MFI Adsorption mass load Humidity Water 500 °C Ammonia Ohmic HEU H MFI H BEA Ionic conductivity Hydrocarbons Electroch. cell NaMF I Ionic conductivity Nitric oxide Electroch. cell NaFA U Catalysis Pentanoic acid Optical fiber MFI adsorption induced reflectivity changes http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Electrical resistance of chromium titanium oxide (CTO) sensors overlaid with zeolites Detection ethanol / isopropanol in dry air operated at 4000C zeolite ethanol CTO isopropanol V BINIONS et al.: IEEE SENSORS JOURNAL, VOL. 11, NO. 5, MAY 2011 http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Typically ethanol / isopropanol react with O-- ions, producing CO2 and releasing electrons => Change of resistance They give similar signal because of same functional group Bare Sensor O-- ethanol CTO isopropanol V BINIONS et al.: IEEE SENSORS JOURNAL, VOL. 11, NO. 5, MAY 2011 http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT The zeolite can make the difference acting as both as a shieve and catalyst enhancing the reaction zeolite ethanol CTO isopropanol V BINIONS et al.: IEEE SENSORS JOURNAL, VOL. 11, NO. 5, MAY 2011 http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT +LTA zeolite Sensor Signal Bare Sensor ethanol Bare Sensor +LTA isopropanol Time BINIONS et al.: IEEE SENSORS JOURNAL, VOL. 11, NO. 5, MAY 2011 http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Hydrocarbon C3H8 Gas Detection – Impedance sensor The ionic conductivity is measured by impedance spectroscopy Z Gunter Hagen and Ralf Moos, SENSOR LETTERS 9, 110–113, 2011 http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Humidity Detection – Optical Sensor methylene blue mordenite zeolite UV–VIS diffuse reflectance spectra change in color upon protonation /deprotonation of dye molecules intercalated into the zeolite http://www.icmmm.net/ S. Sohrabnezhad et al. / Materials Letters 61 (2007)Beijing 2311–2314 2012.9.21-23 UNIVERSITY OF PATRAS D. Kouzoudis QCM (Quartz crystal microbalance ) left: Top electrode, right: back electrode WWW.wikipedia.com http://www.icmmm.net/ 2012.9.21-23 Beijing FORTH-ICEHT UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Sensing of SO2 , FAU zeolite When SO2 is adsorbed on FAU, the mass increase reduces QCM frequency M. Osada, I. Sasaki, M. Nishioka, M. Sadakata, T.Okubo, Microporous and Mesoporous Materials 23 (1998) 287–294 http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Micro-Cantilevers Micro-Cantilevers: rectangularshaped bars of Si, less than 1 μm thick. Adsorption results in bending of the cantilever Mass Loads as small as ~ 5 ng. http://www.icmmm.net/ 2012.9.21-23 Beijing Cantilever array sensor by Hans Peter Lang1,2*, Martin Hegner1, and Christoph Gerber1 UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Humidity sensor using ZSM-5 single crystals Outgased Zeolite Sensor Non-Outgased Zeolite Sensor L.Scandella, G. Binder, T. Mezzacasa, J. Gobrecht, R. Berger, H.P. Lang, Microporous & Mesoporous Materials 21 ( 1998) 403 http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis Detection of dissolved organics in water Adsorption alters zeolite index of refraction → altering the optical reflectivity → reducing reflected signal power. http://www.icmmm.net/ Jian Zhang and Junhang Dong, Langmuir 2005, 21, 8609-8612 2012.9.21-23 Beijing FORTH-ICEHT SEM image of MFI thin films grown on endface of an optical fiber UNIVERSITY OF PATRAS D. Kouzoudis Calibration curve of pentanoic acid http://www.icmmm.net/ 2012.9.21-23 Beijing FORTH-ICEHT UNIVERSITY OF PATRAS D. Kouzoudis Typical Zeolite Synthesis Precursors Commercial Ludox (Si source) Aluminum foil, Al2O3 (Al source) NaOH: Sodium hydroxide (Na source) + organics (catalysts, need removal) TEA: Triethanolamine TPAOH: Tetrapropylamonium hydroxide (also TEOS:tetraethyl orthosilicate) http://www.icmmm.net/ 2012.9.21-23 Beijing FORTH-ICEHT UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Typical Synthesis on Metglas strip Create Nucleation site: Dip substrate in solution with FAU crystals (older solution or commercial batch) Hydrothermal SynthesisQ: Put in autoclave 6 days 4.17 Na2O/ Al2O3/ 6 TEA/ 1.87 SiO2/ 460 H2O T=85 oC (S. Qiu, et al. Microporous Mesoporous Mater., 21, (1998) 245-251) Remove organics: Heat treat composite at 300 oC for 12 hrs Metglas surface before synthesis Metglas’ cross section surface after synthesis http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis Magnetoelastic Sensors http://www.icmmm.net/ 2012.9.21-23 Beijing FORTH-ICEHT UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Magneto-Elastic materials: Alter their shape under magnetic field H a) Spontaneous Magnetostriction b)Forced Magnetostriction Magneto-Elastic ribbons Metglas H=0 Length increase Un-magnetized Magnetized-up H≠0 http://www.icmmm.net/ 2012.9.21-23 Beijing H>>0 UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Magneto-Elastic ribbons An alternating magnetic field induces vibrations in the sensor V = V0 sin(ωt) A pick up coil detects magnetic flux changes → generates AC voltage EMF V0 Frequency The amplitude V0 peaks when excitation frequency equals resonance frequency f0 f0 E / http://www.icmmm.net/ 2012.9.21-23 Beijing Elastic modulus density UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT The resonance frequency depends on mass m and elastic (Young) modulus f0 1 2L E 1 E 2L m a) Mass loads decrease frequency b) E is constant in most solid materials but in magnetoelastic materials it depends on constant (biasing) fields H and stresses σ H and σ increase or decrease frequency •Change on the mass molecules adsorbed in the zeolite’s crystal reflects to changes on the sensor’s resonance frequency http://www.icmmm.net/ 2012.9.21-23 Beijing [1]Grimes CA, Mungle CS, Zeng ZF, et al., Sensors 2 (7): 294-313 JUL 2002 UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Shift in resonance frequency CO2 EMF (mV) zeolite Frequency (kHz) Resonance Frequency [kHz] ME sensor 96,8 N2 96,4 Τ=30οC 96,0 95,6 95,2 94,8 94,4 CO2 94,0 0 20 40 60 80 100 http://www.icmmm.net/ Time [min] Cyclic gas changes 2012.9.21-23 Beijing 120 UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Sensor fabrication Cut of Metglas ribbon (20 mm x 6mm x 30μm) Metglas cleaning i)CH3CCl3 ii)CH3OH MFI sensor Hydrothermal syntesis 19.5 SiO2 + 438 H20 + organics T=185oC FAU sensor Deposition of FAU crystals on Metglas strip by dip coating Autoclave Ozonication to remove organics at 2000 C Hydrothermal syntesis 4.17 Na2O + Al2O3 + 1.87 SiO2 + 460 H2O + organics T=85 oC Heat treat 280 oC 12 hrs to remove organics Zeolite20-30 mm 2826http://www.icmmm.net/ Metglas 30 mm Zeolite20-30 2012.9.21-23 Beijing mm UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Synthesis details Temperature [0C] Ref Zeolite Composition Time (hr) FAU 4.17Na2O:1Al2O3:10TEA:1.87SiO2:460 H2O 170 85 [1] LTA 5SiO2:Al2O3:50Na2O:1000H2O 24 60 [2] MFI 1.5TPAOH :19.5SiO2 :438H2O 24 185 [3] [1] S. Qiu, J. Yu, G. Zhu, O. Terasaki, Y. Nozue, W. Pang, R. Xu, Microporous and Mesoporous Mater., 21, 245, (1998) [2] G. J. Myatt, P. M. Budd, C. Price, and S. W. Carr, J. Mater. Chem. 2, 1103, (1992) [3] Tuan, V. A.; Li, S. G.; Falconer, J. L.; Noble, R. D, Journal of Membrane Science, 196, 111, (2002) http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT LTA FAU IZA Side B IZA Side B Side A Side A 10 15 20 2 theta 25 10 30 MFI 060 040 020 IZA Side B Side A 10 15 2 theta 20 25 http://www.icmmm.net/ 302012.9.21-23 Beijing 15 20 2 theta 25 30 35 UNIVERSITY OF PATRAS D. Kouzoudis FAU FORTH-ICEHT LTA MFI http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis Volatile Organic Compounds http://www.icmmm.net/ 2012.9.21-23 Beijing FORTH-ICEHT UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Volatile Organic Compounds - VOCs • Organic liquids with high vapor pressure • Common by-products in several industrial processes but are also found in everyday life. • Most of the VOCs vapors are considered harmful and their sensing is a necessity VOC Organic http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Some common VOCs Typical VOC Appearance Formaldehyde Plywood, pressed and particle board, fiberboard, adhesives, smoke and fumes Benzene Gasoline fumes, rubber and plastic solvents, smoke, stains, paints, varnishes Xylenes Adhesives, smoke, solvents, enamels, non-lead auto fuels, wall compounds, caulking, clothes and shoe dyes, wall paper, floor coverings, grease cleaner, varnish, pesticides and kerosene vapors Toluene Same as Xylenes, plus vinyl floor and wall coverings and calcium silicate sheets Styrene Paints, synthetic rubber, plastics and resins Toluene diisocyante (TDI) Paints, synthetic rubber, plastics and resins Trichlorethylene Polyurethane foam aerosols Ethyl benzene Solvents Methylene chloride Aerosol finishers and paint strippers Paradichlorobenzene Room deodorizers & mothballs Benzyl chloride & benzal chloride Vinyl tiles covered with Butyl Benzyl Phthalate 2-Butanone (MEK) Same as Xylenes and Toluene Petroleum distillates Cleaning, solvent, paint thinner & stripper materials 4-Phenylcyclohexene Synthetic carpet and pads http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT The VOCs of our work Propylene C3H6 Ethyl-acetate C4H8O2 Propane C3H8 n-Hexane C6H14 http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT c-Hexane C6H12 Benzene C6H6 para-Xylene C8H10 ortho-Xylene http://www.icmmm.net/ 2012.9.21-23 Beijing C8H10 UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Diameter Vapor Pressure [kPa] VOC Formula Safe < (ppm) Propylene C3H6 - 3.9 Å 1152 Propane C3H8 1000 4.3 Å 970 n-hexane C6H14 20 4.3 Å 20 Ethyl-Acetate CH3COOCH2CH3 50 5.2 Å 12.6 p-xylene p-C6H4(CH3)2 100 5.8 Å 1.16 Benzene C6H6 1 5.8 Å 13.4 c-hexane (CH2)6 200 6Å 13 o-xylene o-C6H4(CH3)2 100 6.8 Å 0.88 http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Detection of VOCs with zeolite/ME sensors http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis Experimental Setup VOC http://www.icmmm.net/ 2012.9.21-23 Beijing FORTH-ICEHT UNIVERSITY OF PATRAS D. Kouzoudis Experimental Setup http://www.icmmm.net/ 2012.9.21-23 Beijing FORTH-ICEHT UNIVERSITY OF PATRAS D. Kouzoudis Air VOC Zeolite film 103,50 ME sensor [kHz] 103,25 AIR f 103,00 102,75 102,50 FORTH-ICEHT 0 50 100 150 200 250 Time [min] http://www.icmmm.net/ 2012.9.21-23 Beijing ME sensor UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Propylene C3H6 – Propane C3H8, only 4% mass difference, 7% size difference, sensing selectivity problem C3H 6 (d=4 Å) LTA d=4.1 Å C3H 8 (d=4.3 Å) http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT f [kHz] Air – C3H6 103,0 102,5 102,0 101,5 101,0 100,5 100,0 99,5 99,0 98,5 98,0 400C 1200C 0 100 200 300 800C 400 0 100 200 300 400 5000 50 100 150 200 250 300 350 400 Time [min] Time [min] Time [min] f [kHz] Air – C3H8 103,0 102,5 102,0 101,5 101,0 100,5 100,0 99,5 99,0 98,5 98,0 AIR C3H8 1200C 0 50 100 150 800C 200 0 50 100 150 400C 200 250 0 50 100 150 Time [min] Time [min] http://www.icmmm.net/ 2012.9.21-23 Beijing Vol. 2, 215–218, 2010 Baimpos T, Nikolakis V, Kouzoudis D: Science of Advanced Materials Time [min] 200 250 UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Small Parenthesis: CO2 detection, with FAU, Si/Al = 1.1 -- ++++ -- No net charge 7.4 Å 2.3 Å No dipole moment Size & shape irrelevant, polar interaction Na+ ion CO2 quadruple moment Resonance Frequency [kHz] quadruple moment ≠ 0 96,8 N2 96,4 Τ=30οC 96,0 95,6 95,2 94,8 94,4 CO2 94,0 0 20 40 60 80 100 http://www.icmmm.net/ Time [min] Cyclic gas changes 2012.9.21-23 Beijing 120 UNIVERSITY OF PATRAS D. Kouzoudis o-xylene o-C6H4(CH3)2 100 Kinetic Diameter Å 6.8 c-hexane (CH2)6 200 6 p-xylene p-C6H4(CH3)2 100 5.8 C 6 H6 1 5.8 CH3COOCH2CH3 50 5.2 C6H14 20 4.3 VOC benzene ethylacetate n-hexane Chemical Formula TLV (ppm) http://www.icmmm.net/ 2012.9.21-23 Beijing FORTH-ICEHT FAU 7.4 Å MFI 5.5 Å LTA 4.1 Å UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT VOC 7.4 Å FAU ME sensor 102,4 97,0 AIR AIR 102,0 f [kHz] 96,5 f [kHz] 30 96,0 ppm 70 520 95,5 95,0 FAU film 6200 100 200 300 400 Time [min] 500 ppm 1000 101,2 2000 100,8 o-xylene 0 510 101,6 600 100,4 c-hexane 0 50 100 150 Time [min] http://www.icmmm.net/ 2012.9.21-23 Beijing 200 250 UNIVERSITY OF PATRAS FORTH-ICEHT AIR Benzene 107,0 D. Kouzoudis 101,5 106,5 AIR FAU f [kHz] f [kHz] 101,0 100,5 106,0 105,5 0 530 ppm 100 400 ppm 100,0 1100 200 300 Time [min] 2300 400 99,5 550 p-xylene 0 100 200 2000 300 400 Time [min] 7700 500 600 97,5 AIR Ethyl Acetate 97,0 96,5 AIR f [kHz] f [kHz] 97,0 n-hexane 96,5 96,0 800 96,0 95,5 500 ppm 0 100 200 1000 300 400 Time [min] ppm 1600 6200 2000 95,5 500 0 50 100 150 200 Time [min] http://www.icmmm.net/ 2012.9.21-23 Beijing 250 300 UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT FAU 0,000 c-hexane n-hexane f/fAIR -0,005 benzene -0,010 -0,015 o-xylene ethyl-acetate p-xylene -0,020 0 2000 4000 6000 VOC concentration [ppm] http://www.icmmm.net/ 2012.9.21-23 Beijing 8000 UNIVERSITY OF PATRAS para-Xylene C8H10 D. Kouzoudis FORTH-ICEHT ortho-Xylene C8H10 http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT VOC MFI MFI film ME sensor 5.5 Å 108,0 f [kHz] 107,5 AIR 107,0 2100 ppm 106,5 106,0 AIR 4100 7500 95000 18000 ppm o-xylene c-hexane 105,5 0 100Time 200 [min] 300 0 100 200 300 Time [min] http://www.icmmm.net/ 2012.9.21-23 Beijing 400 500 D. Kouzoudis 108,0 108,0 107,5 107,5 AIR 107,0 AIR 106,5 4100 ppm 12000 95000 benzene f [kHz] f [kHz] UNIVERSITY OF PATRAS 8200 105,5 105,5 200 300 400 2300 106,5 106,0 100 1000 50 440 ppm 107,0 106,0 0 150 FORTH-ICEHT Time [min] p-xylene 0 100 200 300 400 Time [min] 108,0 AIR AIR 28500 107,5 66000 f [kHz] 107,0 106,5 4100 ppm 18000 1300 ppm 95000 106,0 4800 105,5 ethyl 0 100 200 300 acetate Time [min] 400 0 100 n-hexane 200 http://www.icmmm.net/Time [min] 2012.9.21-23 Beijing 300 400 MFI UNIVERSITY OF PATRAS MFI 0,006 n-hexane 0,003 f/fAIR D. Kouzoudis o-xylene 0,000 benzene -0,003 c-hexane p-xylene -0,006 -0,009 ethyl-acetate -0,012 0 25000 50000 75000 VOC concentration [ppm] http://www.icmmm.net/ 2012.9.21-23 Beijing FORTH-ICEHT UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT LTA VOC LTA film ME sensor 4.1 Å 104,0 103,5 AIR f [kHz] 103,0 AIR 80 ppm 270 102,5 1200 4000 ppm 1200 102,0 18000 92000 6200 101,5 c-hexane o-xylene 101,0 0 100 200 300 400 Time [min] 500 600 0 100 200 300 Time [min] http://www.icmmm.net/ 2012.9.21-23 Beijing 400 D. Kouzoudis 104,0 104,0 103,5 AIR 103,5 103,0 1300 4000 ppm 102,5 19000 102,0 95000 101,5 101,0 f [kHz] f [kHz] UNIVERSITY OF PATRAS 0 100 200 300 400 Time [min] AIR 103,0 110 350 ppm 102,5 1600 LTA 8200 102,0 101,5 benzene FORTH-ICEHT 101,0 p-xylene 0 100 200 300 400 500 Time [min] 104,0 AIR f [kHz] 103,5 AIR 103,0 1200 ppm 102,5 142000 28000 18000 102,0 ethyl acetate 101,5 101,0 1900 6200 ppm 3900 0 100 85000 200 300 Time [min] 400 n-hexane 0 100 200 300 400 Time [min] http://www.icmmm.net/ 2012.9.21-23 Beijing 500 600 UNIVERSITY OF PATRAS D. Kouzoudis LTA 0,000 -0,003 f/fAIR c-hexane n-hexane -0,006 benzene p-xylene -0,009 o-xylene -0,012 0 25000 ethyl-acetate 50000 75000 VOC concentration [ppm] http://www.icmmm.net/ 2012.9.21-23 Beijing FORTH-ICEHT UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Results Numbers: Measured ppm levels by the three sensors. Dashes: no detection Marks √ and × : whether a VOC molecule fits in pore or not. VOC oxylene chexane benzene pxylene ethylacetate nhexane FAU 6 * 150 30 20 MFI √ √ √ √ LTA × - × - × - × - √ 15 200 * 230 √ 770 √ 90 190 × × × × × * http://www.icmmm.net/ 2012.9.21-23 Beijing √ 700 × UNIVERSITY OF PATRAS FORTH-ICEHT Why signal reversal? Stress MFI 0,006 n-hexane 0,003 f/fAIR D. Kouzoudis o-xylene 0,000 benzene -0,003 c-hexane p-xylene -0,006 -0,009 ethyl-acetate -0,012 0 25000 50000 75000 VOC concentration [ppm] http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS D. Kouzoudis MFI one side film (a) air Metglas 30 mm MFI 30 mm (b) n-hexane (d) (c) benzene c-hexane (f) (e) o-xylene FORTH-ICEHT p-xylene http://www.icmmm.net/ 2012.9.21-23 Beijing Video UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Stress calculations based on beam theory Metglas 30 mm MFI 30 mm Strain Stress n-hexane 4,4 131 p-xylane 2,4 73 benzene 1,2 37 e‰ http://www.icmmm.net/ 2012.9.21-23 Beijing s (Mpa) UNIVERSITY OF PATRAS D. Kouzoudis http://www.icmmm.net/ 2012.9.21-23 Beijing FORTH-ICEHT UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Slow recovery times - Diffusion AIR p-xylene 101,5 f [kHz] 101,0 100,5 400 ppm 100,0 99,5 http://www.icmmm.net/ 2012.9.21-23 Beijing 550 2000 0 100 200 300 400 Time [min] 7700 500 600 UNIVERSITY OF PATRAS f D. Kouzoudis FORTH-ICEHT 101.2 101.0 Theory + data 100.8 100.6 100.4 100.2 20 40 60 80 100 120 140 t Solution a) Thinner zeolite films than 20 mm b) Derivative of Response curve. http://www.icmmm.net/ 2012.9.21-23 Beijing UNIVERSITY OF PATRAS MFI 0,006 n-hexane 0,003 f/fAIR D. Kouzoudis o-xylene 0,000 benzene -0,003 c-hexane p-xylene -0,006 -0,009 ethyl-acetate -0,012 0 25000 50000 75000 VOC concentration [ppm] http://www.icmmm.net/ 2012.9.21-23 Beijing FORTH-ICEHT UNIVERSITY OF PATRAS D. Kouzoudis Effects of stress MFI Metglas 30 mm MFI 30 mm http://www.icmmm.net/ 2012.9.21-23 Beijing FORTH-ICEHT UNIVERSITY OF PATRAS D. Kouzoudis Effects of stress MFI Metglas 30 mm MFI 30 mm http://www.icmmm.net/ 2012.9.21-23 Beijing FORTH-ICEHT UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT Stress calculations based on beam theory Metglas 30 mm MFI 30 mm Strain Stress n-hexane 4,4 131 p-xylane 2,4 73 benzene 1,2 37 e‰ http://www.icmmm.net/ 2012.9.21-23 Beijing s (Mpa) UNIVERSITY OF PATRAS D. Kouzoudis MFI one side film (a) air (b) n-hexane (d) (c) benzene c-hexane (f) (e) o-xylene p-xylene http://www.icmmm.net/ 2012.9.21-23 Beijing FORTH-ICEHT UNIVERSITY OF PATRAS D. Kouzoudis Conclusions • Zeolite films excellent sensing active layers with nanopores • High selectively on gas size, shape, polarity • Room temperature operation • High specific surface • Adsorption stress plays role • Drawback: Slow recovery time due to diffusion http://www.icmmm.net/ 2012.9.21-23 Beijing FORTH-ICEHT UNIVERSITY OF PATRAS D. Kouzoudis http://www.icmmm.net/ 2012.9.21-23 Beijing FORTH-ICEHT UNIVERSITY OF PATRAS D. Kouzoudis FORTH-ICEHT nd 2 the International Conference on Management, Manufacturing and Materials Engineering ICMMM 2012 Beijing, China Sept. 21-23 2012 http://www.icmmm.net/ http://www.icmmm.net/ 2012.9.21-23 Beijing
