Study on the Relationship between Structure of Supramolecular Ion Material and Performance of Humidity Sensing

相对湿度是许多领域的关键参数，环境湿度与人们的生活密切相关，因此对湿度进行测量和控制是各个领域中值得关注的问题之一. 在前期的研究中，作者制备了一种新型的超分子离子材料（SIM），它是由基于咪唑的双阳离子（如1,10-双（3-甲基咪唑-1-基）癸烷，C10(mim)2）和电活性二阴离子（如2,2\'-连氮基-双（3-乙基苯并噻唑啉-6-磺酸），ABTS）组成的，发现其对湿度具有敏感且快速的响应. 在此基础上，本文制备了6种不同碳链（C4，C6，C8，C10，C12，C14）的咪唑基化合物，发现其中3种（C10，C12，C14）可与ABTS形成水稳定的SIM. 循环伏安法、计时电流法以及石英晶体微量天平表征了这些超分子离子材料的湿度传感性能，发现基于C12的SIM具有最佳的湿度传感性能. 同时，SEM结果显示随着碳链的增加，离子材料的厚度变薄并且形态变得不规则. 因此，作者认为疏水作用和材料比表面积均会影响湿度传感的灵敏度. 本研究为发展新的湿度响应的离子传感材料奠定了基础.Humidity measurement and control is one of the most notable issues in various areas, such as climate, industry, agriculture, electronics, especially human comfort and health. In our previous study, we have found that a new kind of supramolecular ionic material (SIM), consisting of an imidazolium-based dication (e.g., 1,10-bis(3-methylimidazolium-1-yl) decane, C10(mim)2) and electroactive dianionic (e.g., 2,2\'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid), ABTS), shows ultrasensitive and ultrafast response towards humidity sensing. Herein we prepared six kinds of imidazolium-based dications with different carbon chain lengths (i.e., C4, C6, C8, C10, C12, C14), and found that three of them (i.e., C10, C12, C14) could form water-stable SIM with ABTS. Cyclic voltammetry, chronoamperometry and quartz crystal microbalance were used to characterize the humidity sensing performance of these supramolecular ionic materials. The results show that the C12-based SIM has the best humidity sensing performance compared with the other two kinds of SIM. Moreover, SEM images show that the thickness of the ionic material became thinner with the increase of the carbon chain length. We, thus, conclude that both the hydrophobic interaction and the specific surface area of SIMs would contribute to the performance of humidity response. This paper would lay the foundation for the development of new ionic compound for humidity sensing.This research was supported by the National Natural Science Foundation of China (No. 21475138).作者联系地址：1. 湘潭大学化学学院，环境友好化学与应用教育部重点实验室，湖南 湘潭 411105；2. 北京分子科学国家实验室，中国科学院化学研究所活体分析化学重点实验室，北京 100190Author's Address: 1. Key Laboratory of Environmental Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan, Hunan 411105, China; 2. Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, the Chinese Academy of Sciences, Beijing 100190, China通讯作者E-mail：[email protected]

An Enzymatic Ethanol/O2 Biofuel Cell Powered by Commercial Vodka Fuel

本文以乙醇脱氢酶（ADH）和胆红素氧化酶（BOD）为生物催化剂，以碳纳米管为电极材料，构筑了全酶型乙醇/氧气生物燃料电池. 将乙醇脱氢酶负载于单壁碳纳米管（SWCNT）上，采用亚甲基绿（MG）为NADH的电化学催化剂，实现乙醇的生物电化学催化氧化，制备了生物燃料电池ADH/MG/SWCNT/GC的电极（阳极）. 同时，将胆红素氧化酶固定于单壁碳纳米管上，通过其直接电子转移，实现了氧气的生物电化学催化还原，制得生物燃料电池的BOD/SWCNT/GC阴极. 据此构筑了全酶型的无膜生物燃料电池，在空气饱和40 mmol·L-1乙醇磷酸缓冲溶液中该电池开路电压为0.53 V，最大输出功率密度为11 μW·cm-2. 以商品化伏特酒作为燃料，该生物燃料电池最大输出功率为3.7 μW·cm-2.This study demonstrates the performance of a new type alcohol/O2 biofuel cell assembled by using alcohol dehydrogenase (ADH) and bilirubin oxidase (BOD) as the biocatalysts of the bioanode and the biocathode for the bioelectrocatalytic oxidation of alcohol and reduction of oxygen, respectively. To construct the bioanode and the biocathode, single-walled carbon nanotubes (SWCNTs) were used. In the bioanode, SWCNTs were used as the supporting materials for both methylene green (MG) which was used as the electrocatalyst for the oxidation of NADH and ADH. The as-constructed MG/ADH/SWCNTs-based bioanode exhibits a good activity toward the bioelectrocatalytic oxidation of ethanol. In the biocathode, the use of SWCNTs essentially facilities the direct electron transfer of BOD, and thereby enables the bioelectrocatalytic reduction of oxygen into water at a relatively high potential. An ethanol/O2 biofuel cell configuration was then assembled by utilizing the MG/ADH/SWCNTs as the bioanode and the BOD/SWCNTs as the biocathode. The biofuel cell gives a maximum power output of 11 μW·cm-2 in the presence of 40 mmol·L-1 ethanol as biofuel under ambient air in phosphate buffer (pH 7.0). Finally, we demonstrate that the ethanol/O2 biofuel cell could be powered by commercially available Vodak, giving a maximum power output of 3.7 μW·cm-2.国家自然科学基金项目（No. 21321003，No. 21175012）资助作者联系地址：1. 中国科学院化学研究所，北京 100190；2. 北京理工大学化工与环境学院，北京 100081Author's Address: 1. Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, the Chinese Academy of Sciences CAS, Beijing 100190, China; 2. School of Chemical Engineering and Environment, Beijing Institute of Technology, Beijing 100081, China通讯作者E-mail：[email protected]

In-situ characterization of C-60 coalescence reaction

UV radiation-induced coalescence reaction of C-60 were in situ monitored by Raman spectroscopy for the first time, and the process was also characterized by STM and laser desorption mass spectrometry. The Raman measurement reveal that, after the coalescence reaction, the vibration bands corresponding to the highly symmetric A(g) mode of the C-60 molecules either disappear or become very weak, while the bands from other vibration modes just get broaden and red-shifted, suggesting that the coalesced products are larger conjugated molecules but with lower symmetry. The STM measurements show the growth of the coalesced products which eventually form a film. (C) 1999 Elsevier Science B.V. All rights reserved

Collapse of a mass-selected C-60 ion beam collided on crystal surfaces

Mass-selected C-60 ion beams were accelerated to different kinetic energies and deposited on the (0001) surface of highly oriented pyrolytic graphite and the (111) surface of a gold single-crystal. Scanning tunnelling microscopy (STM), Raman spectroscopy and laser desorption mass spectrometry were used to characterize the deposited species. The STM images showed that C-60 molecules colliding on the surface were not dissociated, but their cages collapsed and deformed to planar structures. The Raman spectra of the deposited species are different from the spectral feature of fullerene, and they were similar to that from the glassy carbon instead. The deposited species were desorbed and mass analysed. Both positive and negative C-60 ions were observed in the desorption mass spectra confirming that the species collapsing on the solid surface were the C-60 clusters. It was also found that the collision energy resulting in the collapse of the cage structure of C-60 was around 400 eV, and that fragmentation of the collapsed species does not occur if the energy does not exceed 1 kV

Collapse of a mass-selected C60 ion beam collided on crystal surfaces

地址: 1. XIAMEN UNIV, INST CHEM PHYS, STATE KEY LAB PHYS CHEM SOLID SURFACES, XIAMEN 361005, PEOPLES R CHINA 2. XIAMEN UNIV, DEPT CHEM, XIAMEN 361005, PEOPLES R CHINAMass-selected C-60 ion beams were accelerated to different kinetic energies and deposited on the (0001) surface of highly oriented pyrolytic graphite and the (111) surface of a gold single-crystal. Scanning tunnelling microscopy (STM), Raman spectroscopy and laser desorption mass spectrometry were used to characterize the deposited species. The STM images showed that C-60 molecules colliding on the surface were not dissociated, but their cages collapsed and deformed to planar structures. The Raman spectra of the deposited species are different from the spectral feature of fullerene, and they were similar to that from the glassy carbon instead. The deposited species were desorbed and mass analysed. Both positive and negative C-60 ions were observed in the desorption mass spectra confirming that the species collapsing on the solid surface were the C-60 clusters. It was also found that the collision energy resulting in the collapse of the cage structure of C-60 was around 400 eV, and that fragmentation of the collapsed species does not occur if the energy does not exceed 1 kV