木质纳米纤维素基碳气凝胶构建机制及其吸附行为与电学性能

Wood-based nanocellulose aerogels, composed of interconnected three dimensional (3D) networks, have attracted intensive attention because of their unique physical properties, such as low density, flexible, and high porosity. However, the aerogels also have some problems such as non-resilience, combustible, nonconductive and oleophobic, when used for special applications. Although the aerogels can be functionalized by a series of biological/physical/chemical methods, the complex equipments and expensive processing costs dramatically hamper the large-scale production of these aerogels for industry application. Here, lightweight, resilience, and conductive carbon aerogels will be produced from wood-based nanocellulose, via a facile route by pyrolyzing wood nanocellulose aerogels with inert gas protection. The effects of heating stage, temperature increasing/decreasing rate, maximum carbonization temperature, holding temperature and holding time on the structures and characteristics of carbon aerogels, will be investigated systematically. The construction mechanism and multifunctional characteristics of the carbon aerogels will be subsequently illustrated. As the carbon aerogels are ultra-light, high-elastic, non-combustible, hydrophobic and lipophilic, the adsorption behavior of the aerogels for a wide range of organic solvents and oils will be studied, to show their excellent adsorption ability, recyclability and selectivity. As the carbon aerogels are electrical conductive, their conductivity and electrochemical properties will be researched, to reveal their potential applications for elastic conductor and supercapacitor.

木质纳米纤维素气凝胶因具有低密度、柔韧、高孔隙率等特点，作为一种新型的三维块体材料，日渐受到关注。但是，这一材料在某些特殊领域应用时，也存在一定缺陷，如不具有弹性、易燃、不导电、亲水疏油等。虽然采用改性方法可赋予气凝胶新的功能，但复杂的加工工序及昂贵的制造成本，限制了这一材料的工业化应用前景。本研究拟采用高温碳化方法处理木质纳米纤维素气凝胶，在惰性气氛保护下，将高结晶度的纳米纤维素转变成无定型的碳纳米纤维，制备超轻、高弹、导电型碳气凝胶。研究碳化过程中的升温阶段、升温速度、最高碳化温度、阶段保温温度、保温时间、降温速度等对碳气凝胶结构与特征的影响。明确木质纳米纤维素碳气凝胶的构建机制，挖掘碳气凝胶的多种效能。充分利用碳气凝胶超轻、高弹、不燃、疏水亲油的特征，研究其对油污及有机溶剂的吸附行为。充分研究碳气凝胶的导电性能与电化学性能，发掘其作为弹性导体及超级电容器材料的应用潜力。

以木质纳米纤维素为基本构筑单元制备的气凝胶具有低密度、柔韧、高孔隙率等特点，使得这一材料作为一种新型的三维块体材料，日渐受到关注。但是，纳米纤维素气凝胶在某些特殊领域应用时，也存在一定缺陷，如不具有弹性、易燃、不导电、亲水疏油等。虽然采用改性方法可赋予气凝胶新的功能，但复杂的加工工序及昂贵的制造成本，限制了这一材料的应用前景。本研究采用高温碳化方法处理木质纳米纤维素气凝胶，将高结晶度的纳米纤维素转变成无定型的碳纳米纤维，制备出了一系列超轻、高弹、导电性能优异的碳气凝胶。开发了这些材料在环境纯化、弹性导体等领域的应用潜力，同时揭示了相关科学问题的科学机制，主要成果如下：.1、系统研究了碳化过程中的升温阶段、升温速度、最高碳化温度、阶段保温温度、保温时间等对碳气凝胶结构与特征的影响，并探索出了优化的碳化参数，在此基础上利用纳米纤维素为构筑单元，制造了一系列新型的气凝胶/泡沫与碳气凝胶材料。.2、研究并揭示了碳气凝胶的疏水亲油机制，结合碳气凝胶兼具的耐低/高温的热稳定性、弹性等优点，研究了碳气凝胶作为吸附剂对油和有机溶剂的吸附行为。结果表明：（1）碳气凝胶对不同类型的油及有机溶剂均具有非常高的吸附能力，吸附值为7422至22356。（2）在苛刻条件下，如高温或者低温，以及面对腐蚀性液体，碳气凝胶仍能够保持自身结构完整性，并仍然可以对油污及有机溶剂保持较高的吸附效率。.3、利用木材、竹材、麻、棉花等衍生的纳米纤维素制备碳气凝胶，对比研究了碳气凝胶的结构与性能差异。研究了碳气凝胶的导电性能与电化学性能。在纳米纤维素表面原位聚合聚吡咯，并制备复合气凝胶，经进一步碳化处理后，制备了氮掺杂碳气凝胶。研究了这些碳气凝胶作为弹性导体及超级电容器材料的应用潜力。.4、严格按照计划任务书完成研究规划，共发表SCI论文4篇，其中3篇为封面文章。另有一篇综述已投稿给Chemical Society Review（影响因子：38.618）,正在审稿中。获得授权发明专利3项。