木质纤维生物质制备碳材料及其在超级电容器中的应用

发布时间：2018-06-20 11:48

本文选题：木质纤维生物质 + 活性炭　；参考：《西北大学》2017年硕士论文

【摘要】：木质纤维生物质具有可再生、来源广泛和廉价易得等特点,对木质纤维生物质的高值利用能够有效缓解当前社会对能源的需求。本文研究了木质纤维生物质制备两种碳材料的方法,并将制备的碳材料用作超级电容器的电极材料,进行了电化学性能表征,具体内容如下:1.以长柄扁桃壳为例,提出了综合利用木质纤维生物质这类可再生资源的方法,同时制备生物乙醇和活性炭,其中乙醇的最大产量为0.0158 gg-1,活性炭比表面积高达2059 m2 g-1。对制备的活性炭进行了 SEM、FTIR、XRD和BET表征并将其用作超级电容器的电极材料。在电流密度为0.5 Ag-1时,活性炭的比电容为358.4 Fg-1,在电流密度为5 A g-1时循环1000次,活性炭的电容器电容为初始电容的86.3%。将长柄扁桃壳转换为乙醇和活性炭并将活性炭用作超级电容器的电极材料为木质纤维生物质的综合利用提供了重要借鉴。2.三维多孔石墨烯在能量的转换和存储中有着广泛的应用,其复杂的制备过程和较高的生产成本仍然是工业化应用中的重大挑战。该工作首次发现当氧化钙与木质纤维生物质的质量比增大时,碳材料的结构由活性炭逐步转变为类石墨烯,对该三维多孔类石墨烯进行了 SEM、TEM、XPS、Raman、XRD和BET表征并将其用作超级电容器的电极材料。在电流密度为1Ag-1充放电时,类石墨烯的比电容为136Fg-1,当电流密度增大至100 Ag-1时,类石墨烯的比电容为105 Fg-1。在电流密度10 Ag-1时循环充放电10000次后类石墨烯的比电容为初始电容的97%。该研究不仅为以木质纤维生物质为原料制备碳材料开辟了新思路,而且为三维多孔类石墨烯的制备和应用提供了一种全新的方法。3.对类石墨烯的形成机理进行了初步的研究。研究发现在氧化钙与木质纤维生物质质量比较小时,氧化钙主要作为木质素裂解的催化剂,当氧化钙与木质纤维生物质质量比增大时,氧化钙不仅作为催化剂,同时也是石墨烯沉积的模板。该工作首次提出自活化色谱柱模型来解释氮气流速对碳材料表面积的影响,为碳材料的可控性制备提供重要依据。
[Abstract]:Lignocellulosic biomass has the characteristics of renewable, wide source and cheap and easy to obtain. The high value utilization of lignocellulosic biomass can effectively alleviate the demand for energy in the current society. In this paper, the methods of preparing two kinds of carbon materials from lignocellulosic biomass were studied. The prepared carbon materials were used as electrode materials for supercapacitors and their electrochemical properties were characterized. The main contents are as follows: 1. Taking almond hulls as an example, a comprehensive method of utilizing wood fiber biomass as renewable resources was put forward. Bioethanol and activated carbon were prepared simultaneously. The maximum yield of ethanol was 0.0158 gg-1, and the specific surface area of activated carbon was up to 2059 m2 g ~ (-1). The prepared activated carbon was characterized by SEM FTIR XRD and BET and used as electrode material for supercapacitors. When the current density is 0.5 Ag-1, the specific capacitance of activated carbon is 358.4 Fg-1, and the capacitor capacitance of activated carbon is 86.3% of the initial capacitance when the current density is 5 A g ~ (-1). The conversion of almond shell to ethanol and activated carbon and the use of activated carbon as electrode material of supercapacitor provide important reference for the comprehensive utilization of lignofiber biomass. Three-dimensional porous graphene has been widely used in energy conversion and storage. Its complex preparation process and high production cost are still major challenges in industrial applications. It was found for the first time that when the mass ratio of calcium oxide to lignocellulosic biomass increased, the structure of carbon materials gradually changed from activated carbon to graphene. The three-dimensional porous graphene was characterized by SEMMOTEMN XPSN Raman XRD and BET and used as electrode material for supercapacitors. When the current density is 1Ag-1, the specific capacitance of graphene is 136Fg-1.When the current density increases to 100 Ag-1, the specific capacitance of graphene is 105Fg-1. When the current density is 10 Ag-1, the specific capacitance of graphene is 97% of the initial capacitance after 10000 cycles. This study not only opens up a new idea for the preparation of carbon materials from woody fiber biomass, but also provides a new method for the preparation and application of three-dimensional porous graphene. The formation mechanism of graphene was preliminarily studied. It was found that when the mass ratio of calcium oxide to wood fiber biomass was small, calcium oxide was mainly used as catalyst for lignin pyrolysis. When the mass ratio of calcium oxide to lignofiber biomass increased, calcium oxide was not only used as catalyst. It is also a template for graphene deposition. In this work, a self-activated chromatographic column model was proposed for the first time to explain the effect of nitrogen flow rate on the surface area of carbon materials, and to provide an important basis for the controllable preparation of carbon materials.
【学位授予单位】：西北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ127.11;TM53

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