Na2O掺杂C12A7材料的结构及其抗菌性能

本文利用溶胶-凝胶方法制备了Na2O掺杂的C12A7(12CaO.7Al2O3-Na2O)材料,通过X-射线衍射(XRD)、电子顺磁共振(EPR)、电感等离子体耦合-原子发射光谱(ICP-AES)和飞行时间质谱(TOF-MS)研究了材料结构与性能。选用金黄色葡萄球菌和大肠杆菌为受试菌种,研究了C12A7-Na2O的抗菌性能。结果表明,Na2O掺杂对C12A7的晶体结构以及材料中的氧负离子的浓度没有显著的影响,且C12A7-Na2O材料具有较高的抗菌性能。利用扫描电镜(SEM)对杀菌前后的金黄色葡萄球菌和大肠杆菌的菌体形态进行了观测,初步探讨了C12A7-Na2O的抗菌机理。     

溶胶-凝胶法制备多孔晶体材料C12A7-Cl-

利用溶胶-凝胶法制备了多孔晶体材料C12A7-Cl- (Ca12Al14O32Cl2), 制备凝胶的原料是四水合硝酸钙、九水合硝酸铝、氯化钙、尿素和乙二醇. 混合溶液经过搅拌2-3 h形成溶胶, 再经350 ℃热处理后形成凝胶体, 最终在流动氩气气氛中1000 ℃烧结后得到材料. 用X射线衍射, 场发射扫描电子显微镜, 热重分析, 电子顺磁共振和离子色谱等方法表征合成的C12A7-Cl-多孔晶体材料. 结果表明, 利用溶胶-凝胶法成功地生成了C12A7 结构, 氯负离子是材料中存储的主要负离子. 此外, 从C12A7-Cl-晶体材料表面发射的氯负离子也被飞行时间质谱观测到. 上述结果说明溶胶-凝胶法可被用于制备C12A7-Cl-晶体材料.     

Ca3Al2Ge3O12:Cr3+的光谱性质及晶场参数计算

为了解Cr3 离子在钙铝锗酸盐Ca3Al2Ge3O12石榴石中的光谱性质,合成了Ca3Al2Ge3O12:Cr3 多晶材料;测量了其X射线衍射图,漫反射光谱,激发、发射光谱等;分析了Cr3 离子在钙铝锗酸盐中的发光特性;计算了其晶场强度(Dq/B),Stokes位移(ΔEs)及黄昆-里斯因子(S)等.在450nm激发下,Ca3Al2Ge3O12:Cr3 室温发射光谱主要由三个宽带及附加其上的弱R线构成,分别对应于Cr3 离子的4T1、4T2、2T2到4A2能级跃迁.低温时R线变得强而锐.通过计算,Dq/B=2.43,ΔEs=1884cm-1,S=5.21.表明在Ca3Al2Ge3O12中Cr3 离子处于较弱的晶场强度,电子-声子耦合较强,为发展可调谐激光材料提供重要线索.     

低温区CsI掺杂的12CaO·7Al2O3型发射材料负离子的发射特性

本文利用潮湿浸渍法将碘化铯(CsI)掺杂至12CaO·7Al2O3(C12A7)型负离子存储发射材料的表面并对其的结构与存储特性进行了X射线衍射和电子顺磁共振的表征,与此同时还对该材料的发射特性、离子发射分支比以及温度对发射强度的影响等方面进行了研究和分析。将实验和表征结果与未掺杂的C12A7进行对比后发现,C12A7表面上CsI的掺入很大程度上改善了该材料的发射特性。掺杂CsI后,在800 V·cm-1的引出场下,发射温度由570℃降低至470℃,与此同时,在同样的发射条件下,其发射强度也明显增强。低温区(<500℃)氧负离子O-的发射纯度接近100%。以上结果表明掺杂CsI至C12A7表面是一种在低温下获得氧负离子O-源的有效途径。     

添加碱金属对甲烷与空气制合成气的催化剂性能的影响

考察了添加在镍基催化剂中的碱金属助剂 ,对甲烷与空气制合成气的催化反应性能的影响 ;并用 TPO、TPR、CO2 程序升温脱附 (TPD)、XPS及 CO脉冲色谱技术 ,对催化剂进行了表征 .实验表明 ,碱金属助剂对降低催化剂结炭有一定的作用 ,催化剂的抗积炭性能为 Ni- K2 O/Ca O- Al2 O3>Ni- L i2 O/Ca O- Al2 O3>Ni- Na2 O/Ca O-Al2 O3>Ni/Ca O- Al2 O3.在实验中发现 ,碱金属的添加 ,可使催化剂的 Ni比表面积变小、吸附 CO2 的能力增强 ,且结合能可发生不同程度的改变 .从而解释了碱土金属助剂对催化剂活性和抗积炭性的影响 .实验显示 ,Ni-L i2 O/Ca O- Al2 O3具有较好的活性和抗积炭性能     

Al掺杂尖晶石LiMn2O4正极材料的性能

尖晶石LiMn2O4作为锂离子电池正极可大电流放电,且成本低、环境友好.采用溶胶-凝胶法制备尖晶石LiMn2O4及Al掺杂材料.使用X-射线衍射(XRD)和扫描电子显微镜(SEM)观察材料结构与形貌.结果表明,复合材料颗粒尺寸300-500 nm,呈类球形.电化学恒流充放电测试表明,Al掺杂尖晶石LiMn2O4电极的循环性明显提高,Al掺杂5%LiMn2O4(by mass,下同)正极在1C倍率充放电100周期循环后的容量保持率为98.2%,1C倍率充电、5C倍率放电下,100周期循环后其容量保持率为99.0%,表现出较优的电化学循环性能.     

Gd_(3(1-x))Al_5O_(12)∶RE_(3X)分立材料芯片制备及发光性能研究

将组合材料芯片技术中四元组合法应用于新型发光材料Gd3(1-x)Al5O12∶RE3X的RE激活剂和敏化剂种类优选.由Gd3Al5O12基体材料芯片获得如下的研究结果:1)在紫外激发下(254 nm)Gd3(1-x)Al5O3∶Eu3x材料具有红色荧光性能;2)Pr(n(Pr)∶n(Eu)<1∶10)、Ce(n(Ce)∶n(Eu)<1∶10)共掺杂时会降低发光强度.光谱分析表明:Pr、Ce能级嵌入,使得激活剂和敏化剂发生共振能量传递,是Gd3Al5O12∶Eu(简称为GAG∶Eu)发光效率降低的主要原因.筛选结果得到柠檬酸盐硝酸盐溶胶凝胶法制备粉体筛选实验结果验证.实验结果表明组合法在发光材料开发上具有高效性.     

BaO对Pd/Al2O3催化性能的影响

以 Pd(C2 H3O2 ) 2 为前身 ,制备了系列 Ba O- Al2 O3复合氧化物负载钯的催化剂 .用质量滴定法 ,测定了复合载体的零电荷点 (pzc) .结果表明 ,体系的 pzc随 Ba O含量的增加而增大 ,在 5 %～ 10 %之间存在一拐点 ,并与XRD所测 Ba O在 Al2 O3上的单层分散阈值相对应 .复合载体在制备中发生固相反应 ,所生成的 Ba Al2 O4可以阻止 Al2 O3的相变 ,并极大地提高载体的热稳定性 ,其中 5 % Ba O的作用最为明显 .Ba O的引入 ,增强了 Pd/Al2 O3对 CO的氧化能力 ,同时 ,提高了其热稳定性     

金属有机骨架材料MIL-53(Al)负载钴催化剂的CO催化氧化反应性能

采用溶剂法合成了热稳定性高的金属有机骨架材料MIL-53(Al)(MIL:Materials of Institut Lavoisier),用此材料为载体负载钴催化剂用于CO的催化氧化反应,并与Al2O3负载的钴催化剂进行了对比.采用热重-差热扫描量热(TG-DSC)、傅里叶变换红外(FTIR)光谱、X射线衍射(XRD)、N2物理吸附-脱附、透射电子显微镜(TEM)、氢气程序升温还原(H2-TPR)等方法对催化剂的结构性质进行了表征.TG和N2物理吸附-脱附结果表明,载体MIL-53(Al)有好的稳定性和高的比表面积;XRD以及TEM结果表明Co/MIL-53(Al)上负载的Co3O4颗粒粒径(平均约为5.03 nm)明显小于Al2O3上Co3O4颗粒粒径(平均约为7.83 nm).MIL-53(Al)的三维多孔结构中分布均匀的位点能很好地分散固定Co3O4颗粒,高度分散的Co3O4颗粒有利于CO的催化氧化反应.H2-TPR实验发现Co/MIL(Al)催化剂的还原温度低于Co/Al2O3催化剂的还原温度,低的还原温度表现为高的催化氧化活性.CO催化氧化结果表明,MIL-53(Al)负载钴催化剂的催化活性明显高于Al2O3负载钴催化剂,MIL-53(Al)负载钴催化剂在160°C时使CO氧化的转化率达到98%,到180°C时CO则完全转化,催化剂的结构在催化反应过程中保持稳定.     

Li_4Ti_5O_(12)亚微米球的制备及其在锂离子电池中的应用

主要合成了具有尖晶石结构的Li4Ti5O12亚微米球电极材料,并研究了其作为锂离子电池负极材料的电化学性能.材料的制备分为三个步骤:TiCl4水解得到金红石相的TiO2,然后将得到的TiO2与LiOH进行水热反应得到中间相LiTi2O4+δ,最后将中间相高温煅烧得到尖晶石结构的Li4Ti5O12.采用XRD、SEM和TEM等手段对材料的结构和形貌进行表征.结果表明,尖晶石相的Li4Ti5O12负极材料具有分级结构,是由20～30nm的小颗粒堆积成约为200～300nm的亚微米球.将制备的Li4Ti5O12材料进行恒电流充放电测试表明,材料具有优异的倍率放电性能和较好的循环可逆性;在1C充放电时,首次放电比容量达到174.3mAh/g,在第5～50次循环过程中仅有微小的不可逆容量损失.采用循环伏安法测得Li+的扩散系数为1.03×10-7cm2/s.研究表明合成的Li4Ti5O12亚微米球在高效可充电锂离子电池中具有良好的应用前景.     

Characterization of C12A7-O- Catalyst and Mechanism of Phenol Formation by Hydroxylation of Benzene

The benzene conversion and phenol selectivity from C6H6/O2/H2O over Ca24Al28O644+·4O-(C12A7-O-) catalyst were investigated using a flow reactor. The benzene conversion increases with the increase of temperature, and the phenol selectivity mainly depends on both reaction temperature and the composition of the mixtures. The changes of the catalyst structure before and after the reactions and the intermediates on the catalyst surface and in the bulk were investigated by XRD, EPR and FT-IR. The catalytic reactions do not cause any damage to the structure of the positively charged lattice framework C12A7-O-, but part of the O- and O2- species in the bulk of C12A7-O- translate to OH- after the reactions. The neutral species and anion intermediate were investigated by Q-MS and TOF-MS respectively. It is suggested that the active O- and OH- species played a key role in the process of phenol formation.     

One-step synthesis of phenol by O- and OH- emission material

A novel approach to the direct synthesis of phenol from benzene was obtained with high benzene conversion (30%) and phenol selectivity (approximately 90%) by using a microporous material [Ca24Al28O64]4+.4O-(C12A7-O-) as catalyst with oxygen and water; active O- and OH- anions are proposed to play important roles in the formation of phenol by hydroxylating the aromatic ring of benzene.     

Reduction features of NO over a potassium-doped C12A7-O- catalyst

The NO reduction features over a noble-metal-free NO(x) storage/reduction catalyst ([Ca24Al28O64](4+*)4O-/K, defined as C12A7-O-/K), including the NO conversion, the N2 selectivity, and sulfur tolerance, were investigated with hydrogen and C3H6 as the reducing agents in a fixed-bed continuous flow reactor. The NO conversion and the N2 selectivity on the C12A7-O-/K catalyst mainly depends on the sample temperature, the percentage of potassium, the reducing agents, and the composition of the mixture of gases. The C12A7-O-/10%K catalyst possessed the highest selective reduction ability (to N2) among the catalysts C12A7-O-/x%K. Over 50% of NO can be reduced to N2 with H2 as the reduction agent at 550-700 degrees C. The C12A7-O-/K catalyst also shows higher NO(x) storage capacity (183.9 micromol/g at about 550 degrees C) as well as sulfur tolerance for both the NO(x) storage and the reduction processes. The catalyst characteristics and the intermediate species formed in the NO storage and reduction processes were investigated by the X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and time-of-flight mass spectrometry. The mechanism of NO(x) reduction was addressed according to the above investigations.     

Bioconversion of 7-Hydroxyflavanone: Isolation, Characterization and Bioactivity Evaluation of Twenty-One Phase I and Phase II Microbial Metabolites

Microbial metabolism of 7-hydroxyflavanone (1) with fungal culture Cunninghamella blakesleeana (ATCC 8688a), yielded flavanone 7-sulfate (2), 7,4'-dihydroxyflavanone (3), 6,7-dihydroxyflavanone (4), 6-hydroxyflavanone 7-sulfate (5), and 7-hydroxyflavanone 6-sulfate (6). Mortierella zonata (ATCC 13309) also transformed 1 to metabolites 2 and 3 as well as 4'-hydroxyflavanone 7-sulfate (7), flavan-4-cis-ol 7-sulfate (8), 2',4'-dihydroxychalcone (9), 7,8-dihydroxyflavanone (10), 8-hydroxyflavanone 7-sulfate (11), and 8-methoxy-7-hydroxyflavanone (12). Beauveria bassiana (ATCC 7159) metabolized 1 to 2, 3, and 8, flavanone 7-O-β-D-O-4-methoxyglucopyranoside (13), and 8-hydroxyflavanone 7-O-β-D-O-4-methoxyglucopyranoside (14). Chaetomium cochlioides (ATCC 10195) also transformed 1 to 2, 3, 9, together with 7-hydroxy-4-cis-ol (15). Mucor ramannianus (ATCC 9628) metabolized 1 in addition to 7, to also 4,2',4'-trihydroxychalcone (16), 7,3',4'-trihydroxyflavanone (17), 4'-hydroxyflavanone 7-O-α-L-rhamnopyranoside (18), and 7,3',4'-trihydroxy-6-methoxyflavanone (19). The organism Aspergillus alliaceus (ATCC 10060) transformed 1 to metabolites 3, 16, 7,8,4'-trihydroxyflavanone (20), and 7-hydroxyflavanone 4'-sulfate (21). A metabolite of 1, flavanone 7-O-β-D-O-glucopyranoside (22) was produced by Rhizopus oryzae (ATCC 11145). Structures of the metabolic products were elucidated by means of spectroscopic data. None of the metabolites tested showed antibacterial, antifungal and antimalarial activities against selected organisms. Metabolites 4 and 16 showed weak antileishmanial activity.     

Microbial metabolism. Part 12. Isolation, characterization and bioactivity evaluation of eighteen microbial metabolites of 4'-hydroxyflavanone

Fermentation of 4'-hydroxyflavanone (1) with fungal cultures, Beauveria bassiana (ATCC 13144 and ATCC 7159) yielded 6,3',4'-trihydroxyflavanone (2), 3',4'-dihydroxyflavanone 6-O-β-D-4-methoxyglucopyranoside (3), 4'-hydroxyflavanone 3'-sulfate (4), 6,4'-dihydroxyflavanone 3'-sulfate (5) and 4'-hydroxyflavanone 6-O-β-D-4-methoxyglucopyranoside (7). B. bassiana (ATCC 13144) and B. bassiana (ATCC 7159) in addition, gave one more metabolite each, namely, flavanone 4'-O-β-D-4-methoxyglucopyranoside (6) and 6,4'-dihydroxyflavanone (8) respectively. Cunninghamella echinulata (ATCC 9244) transformed 1 to 6,4'-dihydroxyflavanone (8), flavanone-4'-O-β-D-glucopyranoside (9), 3'-hydroxyflavanone 4'-sulfate (10), 3',4'-dihydroxyflavanone (11) and 4'-hydroxyflavanone-3'-O-β-D-glucopyranoside (12). Mucor ramannianus (ATCC 9628) metabolized 1 to 2,4-trans-4'-hydroxyflavan-4-ol (13), 2,4-cis-4'-hydroxyflavan-4-ol (14), 2,4-trans-3',4'-dihydroxyflavan-4-ol (15), 2,4-cis-3',4'-dihydroxyflavan-4-ol (16), 2,4-trans-3'-hydroxy-4'-methoxyflavan-4-ol (17), flavanone 4'-O-α-D-6-deoxyallopyranoside (18) and 2,4-cis-4-hydroxyflavanone 4'-O-α-D-6-deoxyallopyranoside (19). Metabolites 13 and 14 were also produced by Ramichloridium anceps (ATCC 15672). The former was also produced by C. echinulata. Structures of the metabolic products were elucidated by means of spectroscopic data. None of the metabolites tested showed antibacterial, antifungal and antiprotozoal activities against selected organisms.     

溶胶-凝胶法制备多孔晶体材料C12A7-C1~-

利用溶胶-凝胶法制备了多孔晶体材料C12A7-Cl~-(Ca_(12)Al_(14)O_(32)Cl_2),制备凝胶的原料是四水合硝酸钙、九水合硝酸铝、氯化钙、尿素和乙二醇.混合溶液经过搅拌2-3 h形成溶胶,再经350℃热处理后形成凝胶体,最终在流动氩气气氛中1000℃烧结后得到材料.用X射线衍射,场发射扫描电子显微镜,热重分析,电子顺磁共振和离子色谱等方法表征合成的C12A7-Cl~-多孔晶体材料.结果表明,利用溶胶.凝胶法成功地生成了C12A7结构,氯负离子是材料中存储的主要负离子.此外,从C12A7-Cl~-晶体材料表面发射的氯负离子也被飞行时间质谱观测到.上述结果说明溶胶-凝胶法可被用于制备C12A7-Cl~-晶体材料.     

New fluoro triazol porphyrin‐cellulose: synthesis,characterization and antibacterial activity

This work describes the modification and the characterization of cellulose that was superficially modified with a cationic fluoro porphyrin. The porphyrin was synthesized and affixed onto the cellulose surface via a copper nanoparticles‐catalyzed Huisgen‐Meldal‐Sharpless. 1,3‐Dipolar cycloaddition has been occurred between azide groups present on the cellulosic surface and porphyrinic alkynes. The modified cellulose fabric was characterized with infrared spectroscopy, and with thermogravimetric analysis by a scanning electron microscopy (SEM). The antibacterial effects of fluoro triazol porphyrin‐cellulose fabric against Escherichia coli O157:H7 (ATCC 43889) and Staphylococcus aureus (ATCC 25923) have been tested, and were excellent. Copyright © 2016 John Wiley & Sons, Ltd.     

Hydride ion as photoelectron donor in microporous crystal

Atomic hydrogen (H0) and trapped electrons generated by UV illumination (lambda approximately 330 nm) at 4 K were observed using electron paramagnetic resonance (EPR) in a 12CaO.7Al2O3 (C12A7) crystal heated in a hydrogen atmosphere. The concentration ratio of generated H0 to the electrons encaged in the subnanometer-sized cages of C12A7 (F+ centers) is almost 1:1, providing direct evidence that a hydride ion, H-, accommodated in the cage by the heat treatment was dissociated to a pair of an H0 and an electron by a UV photon: H- --> H0 + e- (F+). After annealing at 300 K, H0 was completely annihilated, while approximately 60% of the trapped electrons survived. The remaining electrons can hop between neighboring cages and give electrical conductivity to C12A7. The hyperfine splitting of the EPR spectrum of H0 in C12A7 (48.6 mT) is 4% smaller than that of the neutral hydrogen atom (50.6 mT), implying that H0 is trapped at the interstitial sites among the cages.