ZIFs基三维碳纳米材料的制备及在环境电化学中的应用
发布时间：2018-11-01 20:40
【摘要】：为了促进可持续发展,绿色、可再生的燃料电池、超级电容器等清洁能源和过氧化氢传感器等环境监测技术正不断被开发出来,以满足日益增长的能源与环境需求。其中,如何针对这些新兴的能源与环境技术开发出恰当的电极材料,进一步缩小器件体积、并同时提高其能量转化效率和精确度是目前亟待解决的问题。本论文以类沸石咪唑结构(ZIFs)这种新型纳米材料为基础,设计并开发了一系列碳纳米电极。深入探究了电极材料的形貌和结构,研究二者与电化学性能之间的关系,深层次地阐明了ZIFs基碳纳米材料在能源与环境中的应用潜力。具体有以下三个方面:(1)通过引入含镍配位化合物的方式,设计并合成了基于ZIF-67的Co、Ni、N三元掺杂碳纳米材料。得到的碳纳米材料显示出了珊瑚或海绵状形貌,将离散的ZIF-67颗粒聚集成一个整体结构,提供了丰富的微孔隙率和高吡啶氮含量,并形成了 Co-N-C和Ni-N-C键作为多重活性位点。作为电极在酸性和碱性条件下的氧气还原反应(ORR)和氧气析出反应(OER)均显示出了非常强的活性,EOER和EORR之间的过电位差值为0.78 V,ORR和OER的双功能性能超过了商业化Pt/C和大部分非贵金属催化剂。(2)通过ZIF-67与石墨烯复合形成三明治结构,以提高电子传输速率,并在此基础上,通过化学气相沉积(CVD)的方法掺杂硼原子,形成BNC键和Co2B键作为新活性位点,并使吡啶氮含量上升。将此电极材料用于H202检测,可以使线性响应范围提升至0.5 μM～60 mM,检测限低至0.19μM,响应时间约为3 s,性能优于目前报道的同类材料。检测范围在低浓度区(0.5 mM)和高浓度区(0.5 mM)的线性相关系数均能达到0.999以上。(3)通过将ZIFs引入气凝胶中并碳化的方式,设计并合成了 ZIF-7复合纤维素和壳聚糖气凝胶材料,碳化后得到的材料显示出三明治和串珠状的微观结构。这种ZIF-7与气凝胶纤维的复合,可以加快电子在一维或二维方向的传输,使内阻减小。该材料作为电极材料应用于超级电容器中分别显示出150.4F·g-1和173.1F·g-1的比电容和小于2Ω的电荷转移电阻,远高于碳化原料作为电极的比电容,是理想的超级电容器电极材料。
[Abstract]:In order to promote sustainable development, green, renewable fuel cells, supercapacitors and other clean energy and hydrogen peroxide sensors and other environmental monitoring technologies are being developed to meet the increasing energy and environmental needs. Among them, how to develop appropriate electrode materials for these new energy and environmental technologies, further reduce the volume of devices, and improve their energy conversion efficiency and accuracy are the problems to be solved. In this paper, a series of carbon nanoelectrodes were designed and developed on the basis of zeolite imidazole-like structure (ZIFs). The morphology and structure of electrode materials and the relationship between them and electrochemical properties were studied. The application potential of ZIFs based carbon nanomaterials in energy and environment was expounded. There are three aspects as follows: (1) Co,Ni,N ternary doped carbon nanomaterials based on ZIF-67 were designed and synthesized by introducing nickel coordination compounds. The obtained carbon nanocomposites exhibit coral or spongy morphology, aggregating discrete ZIF-67 particles into a single structure, providing rich microporosity and high pyridine nitrogen content. Co-N-C and Ni-N-C bonds were formed as multiple active sites. The oxygen reduction reaction (ORR) and the oxygen precipitate reaction (OER) at acidic and alkaline conditions showed very strong activity. The overpotential difference between EOER and EORR was 0.78 V, and the overpotential difference between EOER and EORR was 0.78 V, and the overpotential difference between EOER and EORR was 0.78 V. The bifunctional properties of ORR and OER are superior to those of commercial Pt/C and most non-noble metal catalysts. (2) the sandwich structure is formed by combining ZIF-67 with graphene to improve the electron transport rate. Boron atoms were doped by chemical vapor deposition (CVD) to form BNC bond and Co2B bond as new active sites, and the content of pyridine nitrogen increased. The linear response range can be raised to 0. 19 渭 m and the response time is about 3 s. The linear response range of the electrode material is better than that of the similar materials reported in this paper. The linear response range of the electrode can be increased to 0. 19 渭 M and the response time is about 3 s. The linear correlation coefficients in the low concentration region (0. 5 mM) and the high concentration region (0. 5 mM) can reach more than 0.999. (3) by introducing ZIFs into aerogels and carbonizing, ZIF-7 composite cellulose and chitosan aerogel materials were designed and synthesized. The carbonized materials showed sandwich and beaded microstructure. The combination of ZIF-7 and aerogel fiber can accelerate the transmission of electrons in one or two dimensional direction and reduce the internal resistance. The specific capacitance of 150.4 F g -1 and 173.1 F g -1 and charge transfer resistance of less than 2 惟 are shown in the supercapacitors as electrode materials, which are much higher than the specific capacitance of carbonized raw materials as electrodes. It is an ideal electrode material for supercapacitor.
【学位授予单位】：中国科学院大学(中国科学院过程工程研究所)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;O613.71
，
本文编号：2305043
[Abstract]:In order to promote sustainable development, green, renewable fuel cells, supercapacitors and other clean energy and hydrogen peroxide sensors and other environmental monitoring technologies are being developed to meet the increasing energy and environmental needs. Among them, how to develop appropriate electrode materials for these new energy and environmental technologies, further reduce the volume of devices, and improve their energy conversion efficiency and accuracy are the problems to be solved. In this paper, a series of carbon nanoelectrodes were designed and developed on the basis of zeolite imidazole-like structure (ZIFs). The morphology and structure of electrode materials and the relationship between them and electrochemical properties were studied. The application potential of ZIFs based carbon nanomaterials in energy and environment was expounded. There are three aspects as follows: (1) Co,Ni,N ternary doped carbon nanomaterials based on ZIF-67 were designed and synthesized by introducing nickel coordination compounds. The obtained carbon nanocomposites exhibit coral or spongy morphology, aggregating discrete ZIF-67 particles into a single structure, providing rich microporosity and high pyridine nitrogen content. Co-N-C and Ni-N-C bonds were formed as multiple active sites. The oxygen reduction reaction (ORR) and the oxygen precipitate reaction (OER) at acidic and alkaline conditions showed very strong activity. The overpotential difference between EOER and EORR was 0.78 V, and the overpotential difference between EOER and EORR was 0.78 V, and the overpotential difference between EOER and EORR was 0.78 V. The bifunctional properties of ORR and OER are superior to those of commercial Pt/C and most non-noble metal catalysts. (2) the sandwich structure is formed by combining ZIF-67 with graphene to improve the electron transport rate. Boron atoms were doped by chemical vapor deposition (CVD) to form BNC bond and Co2B bond as new active sites, and the content of pyridine nitrogen increased. The linear response range can be raised to 0. 19 渭 m and the response time is about 3 s. The linear response range of the electrode material is better than that of the similar materials reported in this paper. The linear response range of the electrode can be increased to 0. 19 渭 M and the response time is about 3 s. The linear correlation coefficients in the low concentration region (0. 5 mM) and the high concentration region (0. 5 mM) can reach more than 0.999. (3) by introducing ZIFs into aerogels and carbonizing, ZIF-7 composite cellulose and chitosan aerogel materials were designed and synthesized. The carbonized materials showed sandwich and beaded microstructure. The combination of ZIF-7 and aerogel fiber can accelerate the transmission of electrons in one or two dimensional direction and reduce the internal resistance. The specific capacitance of 150.4 F g -1 and 173.1 F g -1 and charge transfer resistance of less than 2 惟 are shown in the supercapacitors as electrode materials, which are much higher than the specific capacitance of carbonized raw materials as electrodes. It is an ideal electrode material for supercapacitor.
【学位授予单位】：中国科学院大学(中国科学院过程工程研究所)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;O613.71
，
本文编号：2305043
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