冷凍干燥法制氣凝膠

1、University of Science and Technology of China1. Introduction 2. Synthesis of UFA3. Freeze-drying technique4. ConclusionWhat is the lightest material in the world?AerogelMechanica PropertieslElectrical ConductivitiesThermal AcousticLarge open pores and High internal surface areaLow DensitySynthesis b

2、y Freeze-drying technique Haiyan S，Zhen X，Chao G. Advanced Materials. 2013, 25:2554-2560.CNTs aqueous dispersion 1.0mg/ml，28ml GGO aqueous dispersion 1.0mg/ml，28ml MixingStiring for 1.5 h Haiyan S，Zhen X，Chao G. Advanced Materials. 2013, 25:2554-2560. mixture mold freeze-drying for 2d chemically red

3、uced by N2H4 vapor at 90 for 24 h vacuum-drying at 160 for 24 hMechanism :water became ice，then vapored, left many voidsmold decides the shape Haiyan S，Zhen X，Chao G. Advanced Materials. 2013, 25:2554-2560. Haiyan S，Zhen X，Chao G. Advanced Materials. 2013, 25:2554-2560.(d)(c)(e)(f) Haiyan S，Zhen X，C

4、hao G. Advanced Materials. 2013, 25:2554-2560.冷凍干燥（Freeze-drying）又稱真空冷凍干燥、凍結(jié)干燥、凍干（FD）。1811年 誕生，用于生物體脫水1890年 醫(yī)學(xué)上的首次應(yīng)用，凍干了一批生物器官1932年 引入真空設(shè)備，在生物制品、藥劑以及食品領(lǐng)域迅猛發(fā)展1935年 干燥的過程采用主動加熱，開始應(yīng)用到工業(yè)生產(chǎn)1965年 首先采用凍干技術(shù)制備出金屬超細粉末 如今 在超導(dǎo)材料、超細金屬粉末、精細陶瓷、催化劑、高能電池以及薄膜材料等領(lǐng)域都得到了廣泛的應(yīng)用。孫啟達,冷凍干燥超細粉體技術(shù)及應(yīng)用M.化學(xué)工業(yè)出版社,2006.History of F

5、reeze-dryingPhase diagram of salt-water systemShibing Ye et al, J. Mater. Chem. A, 2013, 1, 34953502SEM images of (a and b) GOA and (c and d) GEA-9Multifunctional Graphene/Platinum/Nafion（全氟磺酸） HybridsLuis Estevez et al. J. Am. Chem. Soc. 2011, 133: 61226125Justin E.Silpe, et al. Langmulr , 2013 , 2

6、9: 8782-8787.Freeze-dryingFreeze-dryingl The as-prepared material shows a uniform particle size distribution and the particle size is much smaller than 300 nm.l the composite delivered a reversible capacity of 125.2 mAhg-1 without obviously fading after 100 cycles.Qiao Y Q, Wang X L, Mai Y J, et al.

7、 Journal of Alloys and Compounds, 2012, 536: 132-137.徐如人, 龐文琴, 霍啟升.無機合成與制備化學(xué)M.高等教育出版社,2009.Salt solution（or colloid ）Spray-freezingCongelationMetal salt ballComposite Oxides Oxides, Matel ultra-fine powdersVacuum dryingPyrolyzation or other treatmentPrepare ultra-fine powderAdavantages：1. Can be obt

8、ained in a homogeneous mixture of the components in solution, suitable for adding trace components, synthesize complex functional ceramic materials nanoparticles.2. Size of nanoparticles range from 1 nm to 50 nm .3. Easy to operate and good in the preparation of high purity ceramic material.Disadvan

9、tages： Efficiency is relatively low, corrosive gas impact the life of the equipment. .uThe principle of Freeze-drying technique uSynthesis of Advanced Materials by Freeze- drying technique has many Advantages:template-freesimpleretain the original structurescalable fabricationuEnlightenment: new win

10、e in an old bottle; new concepts in an old framework1. 孫啟達,冷凍干燥超細粉體技術(shù)及應(yīng)用M.化學(xué)工業(yè)出版社,20062. 徐如人, 龐文琴, 霍啟升.無機合成與制備化學(xué)M.高等教育出版社,2009.3. Han Y, Xu Z, Gao C. Ultrathin graphene nanofiltration membrane for water purificationJ. Advanced Functional Materials, 2013.4. Estevez L, Kelarakis A, Gong Q, et al. Multifunctional graphene/platinum/nafion hybrids via ice templatingJ. Journal of the American Chemical Society, 2011, 133(16): 6122-6125.5. Mecklenburg M, Schuchardt A, Mishra Y K, et al. Aerographite: Ultra Lightweight, Flexible Nanowall, Carbon Microtube Material with Outstanding Mechanical Perfor