冷冻干燥法制气凝胶

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.冷冻干燥（Freeze-drying）又称真空冷冻干燥、冻结干燥、冻干（FD）。1811年 诞生，用于生物体脱水1890年 医学上的首次应用，冻干了一批生物器官1932年 引入真空设备，在生物制品、药剂以及食品领域迅猛发展1935年 干燥的过程采用主动加热，开始应用到工业生产1965年 首先采用冻干技术制备出金属超细粉末 如今 在超导材料、超细金属粉末、精细陶瓷、催化剂、高能电池以及薄膜材料等领域都得到了广泛的应用。孙启达,冷冻干燥超细粉体技术及应用M.化学工业出版社,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, 庞文琴, 霍启升.无机合成与制备化学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. 孙启达,冷冻干燥超细粉体技术及应用M.化学工业出版社,20062. 徐如人, 庞文琴, 霍启升.无机合成与制备化学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