以硝酸铜为前驱体,不采用任何模板,通过逐步水热法合成了花状Cu2O/Cu复合纳米材料.用扫描电镜(SEM)、X射线衍射(XRD)和紫外-可见漫反射光谱(DRS)对样品进行表征.结果表明,花状纳米Cu2O/Cu材料是由长为300-500nm,宽为30-70nm的带状花瓣构...以硝酸铜为前驱体,不采用任何模板,通过逐步水热法合成了花状Cu2O/Cu复合纳米材料.用扫描电镜(SEM)、X射线衍射(XRD)和紫外-可见漫反射光谱(DRS)对样品进行表征.结果表明,花状纳米Cu2O/Cu材料是由长为300-500nm,宽为30-70nm的带状花瓣构成,在可见光区域有很强的吸收.复合材料中Cu的含量可以通过反应时间进行调控.对染料Procion Red MX-5B(PR)的可见光催化降解,Cu能明显提高Cu2O的光催化性能.当Cu质量分数为27%-71%时,复合材料Cu2O/Cu的催化活性明显高于单相Cu2O.与立方体形貌的Cu2O/Cu复合材料相比,花状纳米Cu2O/Cu复合材料对染料PR有更高的催化降解性能.且该复合材料有较高的循环回收利用率.展开更多
A novel integrated nanobiocatalyst system based on an enzyme@silica nanoflower@metal-organic framework （enzyme@SNF@ZIF-8） structure with improved stability is fabricated for the first time. The versatility of this s...A novel integrated nanobiocatalyst system based on an enzyme@silica nanoflower@metal-organic framework （enzyme@SNF@ZIF-8） structure with improved stability is fabricated for the first time. The versatility of this system is validated using penicillin G acylase （PGA） and catalase （CAT） as model enzymes. The microporous ZIF-8 layer can be controlled by varying the number of ZIF-8 coating cycles, which produces PGA@SNF@ZIF-8 nanobiocatalysts with different ZIF-8 layer thicknesses. After the second ZIF-8 coating cycle, a PGA@SNF@ZIF-8（2） structure with a homogeneous and well-intergrown ZIF-8 layer is formed, which possesses excellent mechanical and chemical stability. Moreover, PGA@SNF@ZIF-8（2） shows improved thermal/storage stability and reusability compared with free PGA and PGA immobilized on silica nanoflowers （PGA@SNF）. The obtained CAT-based nanobiocatalysts （CAT@SNF@ZIF-8（2）） also show excellent catalytic performance.展开更多
In this work Gd/La@ZnO nanoflower photocatalyst was successfully synthesized by a co-precipitation method and applied for rhodamine B(Rh B) and tetracycline(TCN) degradation under direct sunlight irradiation.The dopin...In this work Gd/La@ZnO nanoflower photocatalyst was successfully synthesized by a co-precipitation method and applied for rhodamine B(Rh B) and tetracycline(TCN) degradation under direct sunlight irradiation.The doping of rare earth elements extends the optical absorption wavelength of ZnO from UV region(390 nm) to visible-light region(401 nm).In addition,the co-doped ZnO nanoflower exhibits a lower charge recombination efficiency which was confirmed by photoluminescence emission analysis.Moreover,the co-doped ZnO nanoflower exhibits the maximum degradation efficiency of 91% for Rh B and 74% for TCN under sunlight irradiation.The calculated synergistic index of co-doped ZnO is higher than that of the pure ZnO.Reactive radicals’ production was confirmed by terephthalic acid(TA) and nitro-blue tetrazolium(NBT) tests.The holes and hydroxyl(·OH) radicals play the major role in degradation reaction and it was confirmed by scavenger’s test.Moreover,the recycling test confirms the stability of the photocatalyst.展开更多
Finding inexpensive electrodes with high activity and stability is key to realize the practical application of fuel cells. Here, we report the fabrication of three-dimensional （3D） porous nickel nanoflower （3D-PNNF...Finding inexpensive electrodes with high activity and stability is key to realize the practical application of fuel cells. Here, we report the fabrication of three-dimensional （3D） porous nickel nanoflower （3D-PNNF） electrodes via an in situ reduction method. The 3D-PNNF electrodes have a high surface area, show tight binding to the electroconductive substrate, and most importantly, have superaerophobic （bubble repellent） surfaces. Therefore, the electrocatalytic hydrazine oxidation performance of the 3D-PNNF electrodes was much higher than that of commercial Pt/C catalysts because of its ultra-weak gas-bubble adhesion and ultra-fast gas-bubble release. Furthermore, the 3D-PNNF electrodes showed ultra-high stability even under a high current density （260 mA/cm^2）, which makes it promising for practical applications. In addition, the construction of superaerophobic nanostructures could also be beneficial for other gas evolution processes （e.g., hydrogen evolution reaction）.展开更多
不采用任何模板,利用原位逐步水热方法一次性合成了花状Cu2O/Cu复合材料.采用X射线衍射、扫描电镜、高分辨透射电镜和自动吸附仪对样品的相结构、形貌和比表面积进行了表征.以偶氮染料Procion Red MX-5B为探针分子,对复合催化剂进行了...不采用任何模板,利用原位逐步水热方法一次性合成了花状Cu2O/Cu复合材料.采用X射线衍射、扫描电镜、高分辨透射电镜和自动吸附仪对样品的相结构、形貌和比表面积进行了表征.以偶氮染料Procion Red MX-5B为探针分子,对复合催化剂进行了可见光催化表征.结果表明该复合催化剂中的Cu和Cu2O之间存在相互作用,其催化活性远高于单相Cu2O和商用P25粉末,有望成为污水治理的新型材料.展开更多
To improve the contact between platinum catalyst and titanium substrate, a layer of TiO2 nanotube arrays has been synthesized before depositing Pt nanoflowers by pulse electrodeposition. Dramatic improvements in elect...To improve the contact between platinum catalyst and titanium substrate, a layer of TiO2 nanotube arrays has been synthesized before depositing Pt nanoflowers by pulse electrodeposition. Dramatic improvements in electrocatalytic activity （3x） and stability （60x） for methanol oxidation were found, suggesting promising applications in direct methanol fuel cells. The 3x and 60x improvements persist for Pt/Pd catalysts used to overcome the CO poisoning problem.展开更多
以石墨烯为添加剂,利用一步水热法制备出石墨烯包覆三维花状SnS_2纳米结构,制得的复合纳米材料由石墨烯和数十个纳米薄片组装而得的SnS_2纳米花球构成。利用XRD、SEM等对材料的晶体结构和形貌进行表征,同时研究了其电化学性能。在1 000 ...以石墨烯为添加剂,利用一步水热法制备出石墨烯包覆三维花状SnS_2纳米结构,制得的复合纳米材料由石墨烯和数十个纳米薄片组装而得的SnS_2纳米花球构成。利用XRD、SEM等对材料的晶体结构和形貌进行表征,同时研究了其电化学性能。在1 000 m A/g的电流密度下循环50次后,SnS_2/石墨烯复合材料的可逆容量仍然可达503.1 m Ah/g,容量保持率高达82%。展开更多
Flower-like Co3O4 hierarchical microspheres composed of self-assembled porous nanoplates were pre- pared by employing Pluronic F127 block-copolymer as template. The samples were characterized by powder X-ray diffract...Flower-like Co3O4 hierarchical microspheres composed of self-assembled porous nanoplates were pre- pared by employing Pluronic F127 block-copolymer as template. The samples were characterized by powder X-ray diffraction（PXRD）, scanning/transmission electron microscopy（SEM/TEM）, and nitrogen adsorption-desorption at 77 K. The results show that the catalytic activity of Co3O4 nanoflowers for the combustion of ventilation air methane is higher than that of commercial Co3O4. The superior catalytic performance of this material can be related to its dominantly exposed {112} crystal planes and higher content of surface Co3＋.展开更多
文摘以硝酸铜为前驱体,不采用任何模板,通过逐步水热法合成了花状Cu2O/Cu复合纳米材料.用扫描电镜(SEM)、X射线衍射(XRD)和紫外-可见漫反射光谱(DRS)对样品进行表征.结果表明,花状纳米Cu2O/Cu材料是由长为300-500nm,宽为30-70nm的带状花瓣构成,在可见光区域有很强的吸收.复合材料中Cu的含量可以通过反应时间进行调控.对染料Procion Red MX-5B(PR)的可见光催化降解,Cu能明显提高Cu2O的光催化性能.当Cu质量分数为27%-71%时,复合材料Cu2O/Cu的催化活性明显高于单相Cu2O.与立方体形貌的Cu2O/Cu复合材料相比,花状纳米Cu2O/Cu复合材料对染料PR有更高的催化降解性能.且该复合材料有较高的循环回收利用率.
文摘A novel integrated nanobiocatalyst system based on an enzyme@silica nanoflower@metal-organic framework （enzyme@SNF@ZIF-8） structure with improved stability is fabricated for the first time. The versatility of this system is validated using penicillin G acylase （PGA） and catalase （CAT） as model enzymes. The microporous ZIF-8 layer can be controlled by varying the number of ZIF-8 coating cycles, which produces PGA@SNF@ZIF-8 nanobiocatalysts with different ZIF-8 layer thicknesses. After the second ZIF-8 coating cycle, a PGA@SNF@ZIF-8（2） structure with a homogeneous and well-intergrown ZIF-8 layer is formed, which possesses excellent mechanical and chemical stability. Moreover, PGA@SNF@ZIF-8（2） shows improved thermal/storage stability and reusability compared with free PGA and PGA immobilized on silica nanoflowers （PGA@SNF）. The obtained CAT-based nanobiocatalysts （CAT@SNF@ZIF-8（2）） also show excellent catalytic performance.
基金Research Supporting Project(RefRSP-2021/160) King Saud University。
文摘In this work Gd/La@ZnO nanoflower photocatalyst was successfully synthesized by a co-precipitation method and applied for rhodamine B(Rh B) and tetracycline(TCN) degradation under direct sunlight irradiation.The doping of rare earth elements extends the optical absorption wavelength of ZnO from UV region(390 nm) to visible-light region(401 nm).In addition,the co-doped ZnO nanoflower exhibits a lower charge recombination efficiency which was confirmed by photoluminescence emission analysis.Moreover,the co-doped ZnO nanoflower exhibits the maximum degradation efficiency of 91% for Rh B and 74% for TCN under sunlight irradiation.The calculated synergistic index of co-doped ZnO is higher than that of the pure ZnO.Reactive radicals’ production was confirmed by terephthalic acid(TA) and nitro-blue tetrazolium(NBT) tests.The holes and hydroxyl(·OH) radicals play the major role in degradation reaction and it was confirmed by scavenger’s test.Moreover,the recycling test confirms the stability of the photocatalyst.
基金This work was supported by the National Natural Science Foundation of China （Nos. 21271018 and 21125101）, the National Basic Research Program of China （No. 2011CBA00503）, the National High-tech R＆D Program of China （No. 2012AA03A609） and the Program for Changjiang Scholars and Innovative Research Team in University.
文摘Finding inexpensive electrodes with high activity and stability is key to realize the practical application of fuel cells. Here, we report the fabrication of three-dimensional （3D） porous nickel nanoflower （3D-PNNF） electrodes via an in situ reduction method. The 3D-PNNF electrodes have a high surface area, show tight binding to the electroconductive substrate, and most importantly, have superaerophobic （bubble repellent） surfaces. Therefore, the electrocatalytic hydrazine oxidation performance of the 3D-PNNF electrodes was much higher than that of commercial Pt/C catalysts because of its ultra-weak gas-bubble adhesion and ultra-fast gas-bubble release. Furthermore, the 3D-PNNF electrodes showed ultra-high stability even under a high current density （260 mA/cm^2）, which makes it promising for practical applications. In addition, the construction of superaerophobic nanostructures could also be beneficial for other gas evolution processes （e.g., hydrogen evolution reaction）.
文摘不采用任何模板,利用原位逐步水热方法一次性合成了花状Cu2O/Cu复合材料.采用X射线衍射、扫描电镜、高分辨透射电镜和自动吸附仪对样品的相结构、形貌和比表面积进行了表征.以偶氮染料Procion Red MX-5B为探针分子,对复合催化剂进行了可见光催化表征.结果表明该复合催化剂中的Cu和Cu2O之间存在相互作用,其催化活性远高于单相Cu2O和商用P25粉末,有望成为污水治理的新型材料.
文摘To improve the contact between platinum catalyst and titanium substrate, a layer of TiO2 nanotube arrays has been synthesized before depositing Pt nanoflowers by pulse electrodeposition. Dramatic improvements in electrocatalytic activity （3x） and stability （60x） for methanol oxidation were found, suggesting promising applications in direct methanol fuel cells. The 3x and 60x improvements persist for Pt/Pd catalysts used to overcome the CO poisoning problem.
文摘以石墨烯为添加剂,利用一步水热法制备出石墨烯包覆三维花状SnS_2纳米结构,制得的复合纳米材料由石墨烯和数十个纳米薄片组装而得的SnS_2纳米花球构成。利用XRD、SEM等对材料的晶体结构和形貌进行表征,同时研究了其电化学性能。在1 000 m A/g的电流密度下循环50次后,SnS_2/石墨烯复合材料的可逆容量仍然可达503.1 m Ah/g,容量保持率高达82%。
基金Supported by the National Natural Science Foundation of China（Nos.21671147, 51203109） and the Funding of the State Key Laboratory of Coal and Coalbed Methane Co-mining, China.
文摘Flower-like Co3O4 hierarchical microspheres composed of self-assembled porous nanoplates were pre- pared by employing Pluronic F127 block-copolymer as template. The samples were characterized by powder X-ray diffraction（PXRD）, scanning/transmission electron microscopy（SEM/TEM）, and nitrogen adsorption-desorption at 77 K. The results show that the catalytic activity of Co3O4 nanoflowers for the combustion of ventilation air methane is higher than that of commercial Co3O4. The superior catalytic performance of this material can be related to its dominantly exposed {112} crystal planes and higher content of surface Co3＋.
