用扫描电子显微镜对聚苯乙烯 b 聚丙烯酸 (PS b PAA)嵌段共聚物在水中自组装形貌进行了观察。结果表明 :外界环境和制样方法能够影响聚合物的自组装和聚集情况。 0℃时 ,PS38 b PAA2 10 胶束聚集形成纺锤状结构。而在临界条件下 ,缓慢...用扫描电子显微镜对聚苯乙烯 b 聚丙烯酸 (PS b PAA)嵌段共聚物在水中自组装形貌进行了观察。结果表明 :外界环境和制样方法能够影响聚合物的自组装和聚集情况。 0℃时 ,PS38 b PAA2 10 胶束聚集形成纺锤状结构。而在临界条件下 ,缓慢改变体系冷冻 解冻循环次数 ,则会得到这些纺锤结构的花状聚集体。展开更多
Ophiopogonis polysaccharide-iron(Ⅲ)(OPI)was prepared and characterized in the present study.The optimum condition for preparing OPI was as follows:OP and trisodium citrate were mixed at a weight ratio of 4:1 and reac...Ophiopogonis polysaccharide-iron(Ⅲ)(OPI)was prepared and characterized in the present study.The optimum condition for preparing OPI was as follows:OP and trisodium citrate were mixed at a weight ratio of 4:1 and reacted in a water bath at 70°C for 3 h within the pH range of 8.0–8.5.Aggregation morphology or structure of OPI in aqueous solution and solid state was studied by scanning electron microscopy,transmission electron microscopy and small-angle X-ray diffraction.In aqueous solution,OPI could self-assemble into micron vesicles with flower-shaped morphology.Results of X-ray diffraction showed OPI with layered structure.A core-shell model was proposed for OPI.展开更多
The design of selective and efficient covalent organic frameworks(COFs)based electrocatalysts with tunable morphology for efficient CO_(2) reduction reaction(CO_(2)RR)to CH_(4) is highly desirable.Here,two kinds of an...The design of selective and efficient covalent organic frameworks(COFs)based electrocatalysts with tunable morphology for efficient CO_(2) reduction reaction(CO_(2)RR)to CH_(4) is highly desirable.Here,two kinds of anthraquinone-based COFs(i.e.,AAn-COF and OH-AAn-COF)with tunable 1D superstructures(e.g.,nanofibers(NF)and hollow tubes(HT))have been produced via Schiff-base condensation reaction.Interestingly,a rarely reported nanosheet-based self-template mechanism and a nanosheet-crimping mechanism have been demonstrated for the production of COF-based nanofibers and hollow tubes,respectively.Besides,the obtained COF-based superstructures can be post-modified with transition metals for efficient CO_(2)RR.Specifically,AAn-COF-Cu(NF)and OH-AAn-COF-Cu(HT)exhibit superior faradaic-efficiency with CH_(4)(FECH_(4))of 77%(-128.1 mA cm^(-2),-0.9 V)and 61%(-99.5 mA cm^(-2),-1.0 V)in a flow-cell,respectively.Noteworthy,the achieved FECH_(4) of AAn-COF-Cu(NF)(77%)is the highest one among reported crystalline COFs.This work provides a general methodology in exploring morphology-controlled COFs for electrocatalytic CO_(2)RR.展开更多
基金Key Laboratory of Traditional Chinese Medicine Quality and Standard,Gansu University of Chinese Medicine,Lanzhou,China(Grant No.ZYZL18-006)
文摘Ophiopogonis polysaccharide-iron(Ⅲ)(OPI)was prepared and characterized in the present study.The optimum condition for preparing OPI was as follows:OP and trisodium citrate were mixed at a weight ratio of 4:1 and reacted in a water bath at 70°C for 3 h within the pH range of 8.0–8.5.Aggregation morphology or structure of OPI in aqueous solution and solid state was studied by scanning electron microscopy,transmission electron microscopy and small-angle X-ray diffraction.In aqueous solution,OPI could self-assemble into micron vesicles with flower-shaped morphology.Results of X-ray diffraction showed OPI with layered structure.A core-shell model was proposed for OPI.
基金supported by the National Natural Science Foundation of China(21871141,21871142,21901122,22071109 and 92061101)the Natural Science Research of Jiangsu Higher Education Institutions of China(19KJB150011)+3 种基金China Postdoctoral Science Foundation(2018M630572 and 2019M651873)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX201171)Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Foundation of Jiangsu Collaborative Innovation Center of Biomedical Functional Materials.
文摘The design of selective and efficient covalent organic frameworks(COFs)based electrocatalysts with tunable morphology for efficient CO_(2) reduction reaction(CO_(2)RR)to CH_(4) is highly desirable.Here,two kinds of anthraquinone-based COFs(i.e.,AAn-COF and OH-AAn-COF)with tunable 1D superstructures(e.g.,nanofibers(NF)and hollow tubes(HT))have been produced via Schiff-base condensation reaction.Interestingly,a rarely reported nanosheet-based self-template mechanism and a nanosheet-crimping mechanism have been demonstrated for the production of COF-based nanofibers and hollow tubes,respectively.Besides,the obtained COF-based superstructures can be post-modified with transition metals for efficient CO_(2)RR.Specifically,AAn-COF-Cu(NF)and OH-AAn-COF-Cu(HT)exhibit superior faradaic-efficiency with CH_(4)(FECH_(4))of 77%(-128.1 mA cm^(-2),-0.9 V)and 61%(-99.5 mA cm^(-2),-1.0 V)in a flow-cell,respectively.Noteworthy,the achieved FECH_(4) of AAn-COF-Cu(NF)(77%)is the highest one among reported crystalline COFs.This work provides a general methodology in exploring morphology-controlled COFs for electrocatalytic CO_(2)RR.