纤维素纳米纤维生物模板复合气凝胶的合成方法
Summary
提出了纤维素纳米纤维生物模板复合气凝胶的合成方法。由此产生的复合气凝胶材料为催化、传感和氢气储存应用提供了潜力。
Abstract
本文提出了一种合成纤维素纳米纤维生物模板化复合气凝胶的方法。惰性金属气凝胶合成方法往往导致脆弱的气凝胶形状控制不良。使用Carboxy甲基化纤维素纳米纤维(CNFs)形成共价粘结水凝胶,可减少金属离子,如在CNF上,在上临界后控制纳米结构和宏观气凝胶单体形状干燥。在存在乙烯二胺的情况下,使用1-乙基-3-(3-二甲基氨基丙基)盐酸甲酰胺(EDC)实现碳甲基化纤维化纳米纤维的交联。CNF 水凝胶在整个合成步骤中保持其形状,包括共价交联、与前体离子的平衡、高浓度还原剂的金属还原、水中的沉淀、乙醇溶剂交换和 CO2超临界干燥。改变前体钚的电浓度,可以通过直接的电子化学还原来控制最终气凝胶复合材料中的金属含量,而不是依赖于其他预成型纳米粒子的相对缓慢的凝聚溶胶技术。该方法以扩散为基础,将化学物种引入和去除水凝胶,适用于较小的散装几何形状和薄膜。纤维素纳米纤维-铂复合气凝胶的特征,带扫描电子显微镜、X 射线衍射学、热重力分析、氮气吸附、电化学阻抗光谱和循环伏特测量表示具有高表面积、金属化的多孔结构。
Introduction
基斯特勒首先报道的气凝胶,提供比散装材料1、2、3密度低的多孔结构。贵金属气凝胶因其在功率和能源、催化和传感器应用方面的潜力而引起了科学界的兴趣。贵金属气凝胶最近通过两种基本策略合成。一种策略是诱导预先形成的纳米粒子4、5、6、7的凝聚。纳米粒子的溶胶凝聚可以由链接分子驱动,溶液离子强度的变化,或简单的纳米粒子表面自由能量最小化7,8,9。另一个策略是从金属前体溶液9、10、11、12、13的单一还原步骤中形成气凝胶。这种方法还用于形成双金属和合金贵金属气凝胶。第一种策略通常很慢,可能需要长达数周的纳米粒子凝聚14。直接还原方法虽然通常比较快,但宏观气凝胶单体的形状控制较差。
一种可能的综合方法,以解决挑战与控制惰性金属气凝胶宏观形状和纳米结构是采用生物温度15。生物模板利用从胶原蛋白、明胶、DNA、病毒到纤维素等生物分子,为纳米结构的合成提供一个形状导向模板,由此产生的金属纳米结构具有生物模板分子16,17。纤维素纳米纤维作为生物模板很有吸引力,因为纤维素材料具有高天然丰度,其高纵横比线性几何形状,以及化学功能化其葡萄糖单体的能力 18,19 20,21,22,23.纤维素纳米纤维 (CNF) 已用于合成用于光阳极24的三维 TiO2纳米线、用于透明纸电子25的银纳米线 25 和用于催化的铂气凝胶复合材料26.此外,TEMPO氧化纤维素纳米纤维已被用作生物模板和还原剂在制备铂装饰CNF气凝胶27。
这里提出了一种合成纤维素纳米纤维生物模板复合气凝胶的方法。形状控制较差的易碎气凝胶适用于一系列贵金属气凝胶合成方法。用于形成共价水凝胶的Carboxy甲基化纤维素纳米纤维(CNFs)允许减少CNF上的金属离子,如金晶,从而在超临界干燥后控制纳米结构和宏观气凝胶单片形状。Carboxy甲基化纤维素纳米纤维交联是使用1-乙基-3-(3-二甲基氨基丙基)盐酸甲二酰胺(EDC)在乙烯二胺作为CNF之间的链接分子的情况下实现的。CNF 水凝胶在整个合成步骤中保持其形状,包括共价交联、与前体离子的平衡、高浓度还原剂的金属还原、水中的沉淀、乙醇溶剂交换和 CO2超临界干燥。前体子浓度变化允许通过直接减少的气凝胶金属含量来控制最终气凝胶的金属含量,而不是依赖于在溶胶方法中使用的预成型纳米粒子的相对缓慢的凝聚。该方法以扩散为基础,将化学物种引入和去除水凝胶,适用于较小的散装几何形状和薄膜。纤维素纳米纤维-铂复合气凝胶的特征,带扫描电子显微镜、X 射线衍射学、热重力分析、氮气吸附、电化学阻抗光谱和循环伏特测量表示高表面积,金属化的多孔结构。
Protocol
Representative Results
Discussion
这里介绍的贵金属纤维素纳米纤维生物模板气凝胶合成方法,使气凝胶复合材料具有稳定的金属成分。离心后压实纤维纳米纤维的共价交联导致水凝胶在随后的氧化铝在氧化铝的合成步骤中具有机械的持久性,即钠的电平衡、电化学还原、喷皮、溶剂交换,和超临界干燥。水凝胶稳定性在电化学还原步骤中至关重要,因为还原剂溶液的浓度高(2MNaBH 4),并因此产生猛烈的氢进化。本研究中使用的?…
Offenlegungen
The authors have nothing to disclose.
Acknowledgements
作者感谢美国陆军贝内特实验室的斯蒂芬·巴托卢奇博士和约书亚·莫雷尔博士使用他们的扫描电子显微镜。这项工作得到了美国西点军校的教师发展研究基金赠款的支持。
Materials
| 0.5 mm platinum wire electrode | BASi | MW-4130 | Used for auxillery electrode and separately for lacquer coating and use as a working electrode |
| 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) | Sigma-Aldrich | 1892-57-5 | |
| 2-(N-morpholino)ethanesulfonic acid (MES) | Sigma-Aldrich | 117961-21-4 | |
| Ag/AgCl (3M NaCl) Reference Electrode | BASi | MF-2052 | |
| Carboxymethyl cellulose, TEMPO Cellulose Nanofibrils, Dry Powder | University of Maine Process Development Center | No 8 | |
| Ethanol, 200 proof | PHARMCO-AAPER | 241000200 | |
| Ethylenediamine | Sigma-Aldrich | 107-15-3 | |
| Fourier-Transform Infrared (FTIR) Spectrometer, Frontier | Perkin Elmer | L1280044 | |
| Hydrochloric Acid | CORCO | 7647-01-0 | |
| Na2PdCl4 | Sigma-Aldrich | 13820-40-1 | |
| NaBH4 | Sigma-Aldrich | 16940-66-2 | |
| Pd(NH3)4Cl2 | Sigma-Aldrich | 13933-31-8 | |
| Potentiostat | Biologic-USA | VMP-3 | Electrochemical analysis-EIS, CV |
| Scanning Electron Mciroscope (SEM) Helios 600 Nanolab | ThermoFisher Scientific | ||
| Supercritical Dryer | Leica | EM CPD300 | Aerogel supercritical drying with CO2 |
| Surface and Pore Analyzer | Quantachrome | NOVA 4000e | Nitrogen gas adsorption |
| Thermal Gravimetric Analysis | TA instruments | TGA Q500 | |
| Ultrasonic Cleaner | MTI | EQ-VGT-1860QTD | |
| XRD | PanAlytical | Empyrean | X-ray diffractometry |
Referenzen
- Kistler, S. S. Coherent Expanded Aerogels and Jellies. Nature. 127, 741 (1931).
- Du, A., Zhou, B., Zhang, Z., Shen, J. A Special Material or a New State of Matter: A Review and Reconsideration of the Aerogel. Materials. 6 (3), 941 (2013).
- Tappan, B. C., Steiner, S. A., Luther, E. P. Nanoporous Metal Foams. Angewandte Chemie International Edition. 49 (27), 4544-4565 (2010).
- Bigall, N. C., et al. Hydrogels and Aerogels from Noble Metal Nanoparticles. Angewandte Chemie International Edition. 48 (51), 9731-9734 (2009).
- Ranmohotti, K. G. S., Gao, X., Arachchige, I. U. Salt-Mediated Self-Assembly of Metal Nanoshells into Monolithic Aerogel Frameworks. Chemistry of Materials. 25 (17), 3528-3534 (2013).
- Gao, X., Esteves, R. J., Luong, T. T. H., Jaini, R., Arachchige, I. U. Oxidation-Induced Self-Assembly of Ag Nanoshells into Transparent and Opaque Ag Hydrogels and Aerogels. Journal of the American Chemical Society. 136 (22), 7993-8002 (2014).
- Herrmann, A. -. K., et al. Multimetallic Aerogels by Template-Free Self-Assembly of Au, Ag, Pt, and Pd Nanoparticles. Chemistry of Materials. 26 (2), 1074-1083 (2014).
- Ding, Y., Chen, M., Erlebacher, J. Metallic Mesoporous Nanocomposites for Electrocatalysis. Journal of the American Chemical Society. 126 (22), 6876-6877 (2004).
- Liu, W., et al. High-Performance Electrocatalysis on Palladium Aerogels. Angewandte Chemie International Edition. 51 (23), 5743-5747 (2012).
- Shafaei Douk, A., Saravani, H., Noroozifar, M. Three-dimensional assembly of building blocks for the fabrication of Pd aerogel as a high performance electrocatalyst toward ethanol oxidation. Electrochimica Acta. 275, 182-191 (2018).
- Burpo, F. J., et al. Direct solution-based reduction synthesis of Au, Pd, and Pt aerogels. Journal of Materials Research. 32 (22), 4153-4165 (2017).
- Burpo, F. J., et al. A Rapid Synthesis Method for Au, Pd, and Pt Aerogels Via Direct Solution-Based Reduction. JoVE. (136), e57875 (2018).
- Qin, G. W., et al. A Facile and Template-Free Method to Prepare Mesoporous Gold Sponge and Its Pore Size Control. The Journal of Physical Chemistry C. 112 (28), 10352-10358 (2008).
- Hench, L. L., West, J. K. The Sol-Gel Process. Chemical Reviews. 90 (1), 33-72 (1990).
- Sotiropoulou, S., Sierra-Sastre, Y., Mark, S. S., Batt, C. A. Biotemplated Nanostructured Materials. Chemistry of Materials. 20 (3), 821-834 (2008).
- Huang, J., et al. Bio-inspired synthesis of metal nanomaterials and applications. Chemical Society Reviews. 44 (17), 6330-6374 (2015).
- Burpo, F. J., Mitropoulos, A. N., Nagelli, E. A., Ryu, M. Y., Palmer, J. L. Gelatin biotemplated platinum aerogels. MRS Advances. 10, 1-6 (2018).
- Jarvis, M. Cellulose stacks up. Nature. 426, 611 (2003).
- Siró, I., Plackett, D. Microfibrillated cellulose and new nanocomposite materials: a review. Cellulose. 17 (3), 459-494 (2010).
- Dufresne, A. Nanocellulose: a new ageless bionanomaterial. Materials Today. 16 (6), 220-227 (2013).
- Grishkewich, N., Mohammed, N., Tang, J., Tam, K. C. Recent advances in the application of cellulose nanocrystals. Current Opinion in Colloid & Interface Science. 29, 32-45 (2017).
- Eyley, S., Thielemans, W. Surface modification of cellulose nanocrystals. Nanoscale. 6 (14), 7764-7779 (2014).
- Missoum, K., Belgacem, M., Bras, J. Nanofibrillated Cellulose Surface Modification. A Review. Materials. 6 (5), 1745 (2013).
- Li, Z., Yao, C., Wang, F., Cai, Z., Wang, X. Cellulose nanofiber-templated three-dimension TiO2 hierarchical nanowire network for photoelectrochemical photoanode. Nanotechnology. 25 (50), 504005 (2014).
- Hal Koga, ., et al. Uniformly connected conductive networks on cellulose nanofiber paper for transparent paper electronics. Npg Asia Materials. 6, 93 (2014).
- Fal Burpo, ., et al. Cellulose Nanofiber Biotemplated Palladium Composite Aerogels. Molecules. 23 (6), 1405 (2018).
- Gu, J., Hu, C., Zhang, W., Dichiara, A. B. Reagentless preparation of shape memory cellulose nanofibril aerogels decorated with Pd nanoparticles and their application in dye discoloration. Applied Catalysis B: Environmental. 237, 482-490 (2018).
- Coates, J. in A Practical Approach. In Encyclopedia of Analytical Chemistry .doi:10.1002/9780470027318.a5606 (ed. , (2006).
- Sal Wang, ., et al. Cellulose nanofiber-assisted dispersion of cellulose nanocrystals@polyaniline in water and its conductive films). RSC Advances. 6 (12), 10168-10174 (2016).
- Grabarek, Z., Gergely, J. Zero-length crosslinking procedure with the use of active esters. Analytical Biochemistry. 185 (1), 131-135 (1990).
- Shabanpour, B., Kazemi, M., Ojagh, S. M., Pourashouri, P. Bacterial cellulose nanofibers as reinforce in edible fish myofibrillar protein nanocomposite films. International Journal of Biological Macromolecules. 117, 742-751 (2018).
- Brunauer, B., Emmett, P., Teller, P. Adsorption of gases in multimolecular layers. Journal of the American Chemical Society. 60, (1938).
- Barrett, E., Joyner, L., Halenda, P. The determination of pore volume and area distributions in porous substances. I. Computations. 73, (1951).
