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Bing Qin Zhi-Long Yu Jin Huang Yu-Feng Meng Rui Chen Zhi Chen Shu-Hong Yu 《Angewandte Chemie (International ed. in English)》2023,62(5):e202214809
Cellulose aerogels are plagued by intermolecular hydrogen bond-induced structural plasticity, otherwise rely on chemicals modification to extend service life. Here, we demonstrate a petrochemical-free strategy to fabricate superelastic cellulose aerogels by designing hierarchical structures at multi scales. Oriented channels consolidate the whole architecture. Porous walls of dehydrated cellulose derived from thermal etching not only exhibit decreased rigidity and stickiness, but also guide the microscopic deformation and mitigate localized large strain, preventing structural collapse. The aerogels show exceptional stability, including temperature-invariant elasticity, fatigue resistance (∼5 % plastic deformation after 105 cycles), high angular recovery speed (1475.4° s−1), outperforming most cellulose-based aerogels. This benign strategy retains the biosafety of biomass and provides an alternative filter material for health-related applications, such as face masks and air purification. 相似文献
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Jian-Wen ShiHao-Jie Cui Jian-Wei ChenMing-Lai Fu Bin XuHong-Yuan Luo Zhi-Long Ye 《Journal of colloid and interface science》2012,388(1):201-208
In order to more easily separate TiO2 photocatalyst from the treated wastewater, TiO2 film was immobilized on the surface of activated carbon fibers (ACFs) by employing two kinds of coating procedures, dip-coating, and hydrothermal treatment. The effects of coating procedures on microstructure of TiO2-coated ACFs (TiO2/ACFs), such as morphology, porous property, crystal structure, and light absorption characteristics were investigated in detail. The adhesion property between TiO2 film and ACFs was evaluated by ultrasonic vibration, and the photocatalytic activity of TiO2/ACFs was tested by the photocatalytic decoloration of methylene blue solution. The results show that hydrothermal treatment presented many advantages to obtain high-performance TiO2/ACFs photocatalyst in comparison with dip-coating. Hydrothermal treatment could improve the binding property between TiO2 films and ACFs, which endowed the as-obtained TiO2/ACFs photocatalyst with improved reusable performance, and TiO2/ACFs synthesized by hydrothermal treatment presented higher photocatalytic activity. 相似文献
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Three new metal-organic complexes, namely [Zn(POA)2(H2O)2](1), [Zn(POA)2(H2O)2]·2H2O(2) and [Zn(POA)2]n(3), have been synthesized by organic ligand 2-carboxylic acid-4-nitropyridine-1-oxide(POA) and zinc(Ⅱ) ions. The structures of complexes 1~3 are characterized by single-crystal X-ray analysis, XRD powder diffraction analysis, infrared spectroscopy and thermal stability analysis method. Complex 1 belongs to monoclinic system, space group C2/c with a = 22.8215(15), b = 7.5613(16), c = 10.048(3) ?, β = 109.47°, V = 1634.7(6) ?~3, Z = 4, F(000) = 944, Dc = 1.900 g/cm^3, C(12)H(10)N4O(12)Zn, Mr = 467.61 and μ = 1.584 mm-1. The whole molecule presents "V" shape. Complex 2 is a centrosymmetric structure in triclinic system with space group P1: a = 7.4728(5), b = 7.6825(6), c = 8.5184(6) ?, α = 65.975(2), β = 79.87(2), γ = 89.855(2)°, V = 4384.1(5) ?~3, Z = 1, F(000) = 256, Dc = 1.908 g/cm^3, C(12)H(14)N4O(14)Zn, Mr = 503.64 and μ = 1.492 mm-1. Complex 3 is a one-dimensional chain structure belonging to monoclinic system and space group P21/c with a = 4.9456(6), b = 12.5322(14), c = 11.2514(13) ?, β = 97.313(11)°, V = 6916.8(14) ?~3, Z = 2, F(000) = 432, Dc = 2.072 g/cm^3, C(12)H6N4O(10)Zn, Mr = 431.58, and μ = 1.852 mm-1. In three complexes, six oxygen atoms from the surrounding coordination atoms form a ZnO6 distorted octahedral coordination geometry around the zinc ions. Meanwhile, fluorescent properties of the three complexes were investigated at room temperature. The fluorescence spectroscopic analysis demonstrated that the ligand POA shows red-shift after coordinating with the zinc(Ⅱ) ions. 相似文献
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利用密度泛函理论B3LYP方法, 在6-311G*基组水平上对(KN3)n(n=1~5)团簇各种可能的结构进行了几何结构优化, 预测了各团簇的最稳定结构. 并对最稳定结构的振动特性、成键特性、电荷分布和稳定性性质进行了分析研究. 结果表明, 叠氮化合物中叠氮基以直线型存在, KN3团簇最稳定结构为直线型, (KN3)n(n=2~3)团簇最稳定结构为环形结构, (KN3)n(n=4~5)团簇最稳定结构是由(KN3)2团簇最稳定结构形成的平面和空间结构. N-N 键键长在0.1156~0.1196 nm之间, N-K键键长在0.2357~0.2927 nm之间; 叠氮基中间的N原子显示正电性, 两端的N原子显示负电性, 且与K原子直接作用的N原子负电性更强, 金属K原子与N原子之间形成离子键. (KN3)n(n=1~5)团簇最稳定结构的IR光谱最强振动峰均位于2180~2230 cm-1, 振动模式为叠氮基中N-N键的反对称伸缩振动. 稳定性分析显示, (KN3)3团簇具有相对较高的动力学稳定性. 相似文献
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DAI Jian-ying ZHANG Li-fu XIU Zhi-long School of Life Science Biotechnology Dalian University of Technology Dalian P. R. China 《高等学校化学研究》2011,(2):273-276
S-Ribosylhomocysteinase(LuxS) is the key enzyme in the synthetic pathway of a quorum sensing autoinducer AI-2. LuxS from a 2,3-butanediol produced strain Klebisella pneumoniae CICC 10011 was cloned and characterized. The luxS gene is composed of 540 bp with 172 amino acids encoded. The Km value for S-ribosylhomo- cysteine(SRH) was (27±1) umol/L, kcat was (0.112±0.004) s-1 and kcat/Km was 4.4×103 L umol-1·s-1 at 25 ℃. LuxS was activated by divalent metal ions, the highest activity was detected with Co2+ form... 相似文献