Two Highly Stable Proton Conductive Cobalt(II)–Organic Frameworks as Impedance Sensors for Formic Acid

Metal–organic frameworks (MOFs) have been extensively explored as advanced chemical sensors in recent years. However, there are few studies on MOFs as acidic gas sensors, especially proton conductive MOFs. In this work, two new proton-conducting 3D MOFs, {[Co₃(p-CPhHIDC)₂(4,4′-bipy)(H₂O)] ⋅ 2 H₂O}_n ( 1 ) (p-CPhH₄IDC=2-(4-carboxylphenyl)-1 H-imidazole-4,5-dicarboxylic acid; 4,4′-bipy=4,4′-bipyridine) and {[Co₃(p-CPhHIDC)₂(bpe)(H₂O)] ⋅ 3 H₂O}_n ( 2 ) (bpe=trans-1,2-bis(4-pyridyl)ethylene) have been solvothermally prepared and investigated their formic acid sensing properties. Both MOFs 1 and 2 show temperature- and humidity-dependent proton conductive properties and exhibit optimized proton conductivities of 1.04×10⁻³ and 7.02×10⁻⁴ S cm at 98 % relative humidity (RH) and 100 °C, respectively. The large number of uncoordinated carboxylic acid sites, free and coordination water molecules, and hydrogen-bonding networks inside the frameworks are favorable to the proton transfer. By measuring the impedance values after exposure to formic acid vapor at 98 % or 68 % RH and 25 °C, both MOFs indicate reproducibly high sensitivity to the analyte. The detection limit of formic acid vapor is as low as 35 ppm for 1 and 70 ppm for 2 . Meanwhile, both MOFs also show commendable selectivity towards formic acid among interfering solutions. The proton conducting and formic acid sensing mechanisms have been suggested according to the structural analysis, E_a calculations, N₂ and water vapor absorptions, PXRD and SEM measurements. This work will open a new avenue for proton-conductive MOF-based impedance sensors and promote the potential application of these MOFs for indirectly monitoring the concentrations of formic acid vapors.     

A Co(OH)2−graphene nanosheets composite as a high performance anode material for rechargeable lithium batteries

A Co(OH)₂?graphene nanosheets (Co(OH)₂?GNS) composite as a high performance anode material was firstly prepared through a simultaneous hydrothermal method. The structure, morphology and electrochemical performance of the obtained samples were systematically investigated by X-ray diffraction (XRD), transmission electron microscope (TEM) and electrochemical measurements. According to the TEM analysis, the surface of the Co(OH)₂ is surrounded with GNS in the Co(OH)₂?GNS composite. The specific discharge (lithiation) and charge (delithiation) capacities of Co(OH)₂?GNS attain to 1599 and 1120 mAh/g at a current density of 200 mA/g in the first cycle, respectively. After 30 cycles, the reversible capacity of Co(OH)₂?GNS is still 910 mAh/g with the retention of 82%. The particular structure of Co(OH)₂ particles surrounded by the GNS could limit the volume change during cycling and provide an excellent electronic conduction pathway, which could be the main reason for the remarkable improvement of electrochemical performance.     

基于胸腺嘧啶-汞离子-胸腺嘧啶结构和纳米金放大传感器检测汞离子

利用Hg2+与DNA中胸腺嘧啶(T)结合的高度特异性和纳米金在石英晶体微天平(QCM)上的信号放大作用,设计了一种简便灵敏的Hg2+检测方法.纳米金采用柠檬酸钠还原法制备,其表面用末端带巯基的寡核苷酸探针进行自组装修饰,并用6-巯基己-1-醇(MCH)部分取代表面探针,以减少杂交空间位阻.结果表明,寡核苷酸链长为9bp、T个数为7的序列具有较高灵敏度;线性范围为5.0～100 nmol/L;检出限为2.0 nmol/L;Ca2+、Mg2+等其它金属离子无明显干扰.用于环境水样中Hg2+的测定, RSD<2.9%;加标回收率为97.3%～101.2%     

基于细胞色素C/氧化锌的过氧化氢生物传感器

在铟锡氧化物(ITO)导电玻璃上,通过物理气相沉积纳米氧化锌制备了Nano-ZnO/ITO,并采用浸渍法将细胞色素C(Cyt.c)直接修饰于Nano-ZnO膜上,制得了Cyt.c修饰电极(Cyt.c/Nano-ZnO/ITO/CME),构建了基于直接电子传递的过氧化氢(H2O2)生物传感器.Nano-ZnO的X射线衍射光谱表明Nano-ZnO 膜为多晶六边形纤维锌矿结构;扫描电子显微镜(SEM) 表明Nano-ZnO 膜为多孔纳米材料,微粒直径在50～100 nm,且堆积形成多孔Nano-ZnO结构;紫外可见吸收光谱的最大吸收峰为360 nm,室温禁带宽度 3.37 eV.交流阻抗、紫外可见光谱以及循环伏安法证明了吸附在Nano-ZnO上的Cyt.c保持了生物催化活性,并实现了在Nano-ZnO上的直接电子传递.H2O2生物传感器(Cyt.c/Nano-ZnO/ITO/CME)的线性范围5×10-5～5×10-3 mol/L;灵敏度7.2×10-3 A·cm-2·mol/L,检出限4×10-5mol/L; 响应时间约3 s.     

Syntheses, structures, fluorescence and thermal properties of three lanthanide coordination polymers built by N-benzoyl-N′-(4-benzoxy)thiourea

Three novel lanthanide 1-D chain coordination polymers, namely {[Tb(μ₂-L)₂(η²-NO₃)(CH₃OH)(H₂O)]·0.5CH₃OH·0.5H₂O}_n (1), {[Dy(μ₂-L)₂(η²-NO₃)(CH₃OH)(H₂O)]·H₂O}_n (2) and {[Ce(μ₂-L)₂(η²-NO₃)(H₂O)₃]·H₂O}_n (3) (HL=N-benzoyl-N′-(4-benzoxy)thiourea), have been prepared and characterized by IR spectroscopy, elemental analysis and single-crystal X-ray diffraction. The luminescence properties and themostabilities of polymers 1-3 have been determined as well.     

两段变温法水热合成多级孔ZSM-5分子筛及其催化裂化性能

以四丙基氢氧化铵（TPAOH）为单一模板剂,采用低温老化、高温晶化2段变温法合成出了球状多级孔ZSM-5分子筛。利用XRD、FT-IR、NH₃-TPD、SEM、TEM以及氮气吸-脱附等测试对合成样品进行了表征。结果表明：直径约为2 μm左右的球状多级孔ZSM-5分子筛颗粒内的晶间介孔和大孔主要由棒状纳米晶堆积而成的,该产品具有较大的比表面积和介孔孔容。同常规水热法一步合成的微孔ZSM-5分子筛相比,2段变温法合成的多级孔ZSM-5分子筛具有更高的B酸/L酸比例（C_BP/C_LP）、强酸/弱酸比例（C_s/Cw）以及活性位可接近性指数（ACI）。催化裂化评价结果显示,得益于活性位可接近性指数等指标的提高,球状多级孔ZSM-5分子筛比常规合成的微孔ZSM-5分子筛具有更高的转化率和丙烯收率等优异的催化性能。     

杂原子取代型磷酸铝分子筛上丁烯异构化反应

采用水热法合成了Si、Zr杂原子取代的磷酸铝分子筛（APO-11）.研究发现,它们(SAPO-11、ZAPO-11)与APO-11分子筛骨架结构相同（AEL型）；三者表面形貌不同,SAPO-11与APO-11分子筛同为球形颗粒,而ZAPO-11则为棒状晶粒.杂原子的取代能改变APO-11分子筛的酸性质以及微孔分布.反应评价显示,异构化活性SAPO-11>> ZAPO-11 > APO-11；其中SAPO-11分子筛,当Si/Al=0.15时,异构化性能最佳.异构化反应的因子（时间、分压、温度）系统考察发现,主要副产物C3、C5＋与i-C4=的浓度呈现不同的变化趋势,从而证实丁烯选择性异构是通过单分子机理实现的,C3、C5＋是通过双分子历程生成的.     

Studies of the intestinal absorption of the alkaloids in the Wu-tou decoction combined with different incompatible medicinal herbs in a Caco-2 cell culture system using UPLC-MS/MS

In this study, seven alkaloids were detected in Wu-tou decoction using ultra performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MSn). The aim of this study was to investigate the effect of Fritillariae Cirrhosae Bulbus, Fritillariae Thunbergii Bulbus, Pinelliae Rhizoma in different ratios with Wu-tou decoction (2:1, 1:1, 1:2) by measuring the therapeutic effects in Wu-tou decoction of main seven alkaloids including benzoylaconitine (BA), benzoylmesaconitine (BM), benzoylhypaconitine (BH), hypaconitine (HA), fuziline (FU), niaolin (NE) and deoxyaconitine (DA). The permeability of aconitum alkaloids extract through a Caco-2 cell monolayer was analyzed in the absence and presence of Fritillariae Cirrhosae Bulbus, Fritillariae Thunbergii Bulbus, and Pinelliae Rhizoma, respectively. The results showed that Pinelliae Rhizoma could reduce the absorption of the alkaloids and increase the excretion of the alkaloids, which would attenuate the therapeutic effects of Wu-tou decoction. Therefore, Pinelliae Rhizoma is an incompatible herb of Wu-tou decoction because of the inhibition of the absorption of alkaloids in the intestine. And that Fritillariae Cirrhosae Bulbus and Fritillariae Thunbergii Bulbus showed the effects to improve the permeability of the alkaloids in Wu-tou decoction. These effects of these two herbs were similar, but the former was stronger than the latter, which most likely is due to the fact that the compositions of these two traditional Chinese medicines are similar. The in vitro data suggests that the compounds such as fritillary presented in alkaloids in the formula maybe improve the therapeutic function caused by the increased bioavailability of alkaloids in intestine.     

苯丙酮尿症新生儿血斑中辅酶及葡萄糖等物质的分析

苯丙酮尿症(PKU)是新生儿先天性苯丙氨酸羟化酶缺陷所引起的苯丙氨酸代谢障碍疾病.本研究采用超高效液相色谱-质谱联用技术, 测定了5例PKU新生儿出生3天和出生30天后的血斑与20例年龄相仿的正常新生儿血斑中辅酶Q10的绝对含量和辅酶Q9的相对含量,其中,健康新生儿血斑中辅酶Q10的含量为(122.1±24.9) ng/mL,PKU新生儿组的含量为(59.0±12.0) ng/mL.采用气相色谱-质谱联用技术测定了胆固醇和葡萄糖的相对含量.研究结果表明,与对照组相比,PKU新生儿血斑中辅酶Q10、Q9、胆固醇和葡萄糖的含量均显著降低,辅酶Q10的降低与血斑中苯丙氨酸含量升高呈现显著反向相关.本研究结果为PKU患儿的饮食治疗方案提供了依据.     

Syngas Production by Methane Reforming with Carbon Dioxide on Noble Metal Catalysts

A series of noble metal catalysts (Ru, Rh, Ir, Pt, and Pd) supported on alumina-stabilized magnesia (Spinel) were used to produce syngas by methane reforming with carbon dioxide. The synthesized catalysts were characterized using BET, TPR, TPO, TPH, and H2S chemisorption techniques. The activity results showed high activity and stability for the Ru and Rh catalysts. The TPO and TPH analyses indicated that the main reason for lower activity and stability of the Pd catalyst was the formation of the less reactive deposited carbon and sintering of the catalyst.