花状纳米金和球形纳米金的催化活性对比研究

以花状纳米金(AuNFs)或球形纳米金(AuNPs)为催化剂,硼氢化钠为供氢体,在不同温度下以对硝基苯酚为模板发生还原反应。结果表明,该催化反应温度与时间呈负相关。50℃时,AuNFs所需反应时间为7min,37℃时所需时间为15 min,20℃时所需时间为45 min。该反应为准一级动力学反应。AuNFs的Ea值37.97 kJ/mol,比AuNPs的Ea值51.51 kJ/mol小,说明花状纳米金比球形纳米金具有更高的催化活性。     

Ba3V2O8∶Eu3+纳米花的制备及光致发光性能研究

采用复合氢氧化物媒介法制备了Ba3V2O8∶Eu3+纳米花。利用SEM-EDS、XRD、TEM和XPS对晶体的形貌和尺寸、结构和化学组成进行了表征。结果表明产物是由厚度约20nm的纳米片组成的花状Ba3V2O8∶Eu3+纳米晶体。荧光光谱测定发现Ba3V2O8∶Eu3+晶体在紫外光和蓝光激发下都能产生591和612nm 2个强发射峰,表明其具有将紫外光和蓝光转换成红光的能力,可以进一步应用于光转换和光发射领域。探讨了Ba3V2O8∶Eu3+纳米花的发光机理。     

碱式碳酸镁纳米花的热分析干燥动力学研究

以六水氯化镁和尿素为原料,采用均匀沉淀法制备出碱式碳酸镁纳米花。在不同干燥介质温度和不同物料床层厚度下,得到碱式碳酸镁纳米花的干燥曲线和干燥速率曲线。采用热分析动力学技术对干燥动力学实验数据进行处理后,得到碱式碳酸镁纳米花的干燥微分机理函数为f(1-MR)=6MR2/3(1-MR1/3)1/2,干燥积分机理函数为g(1-MR)=(1-MR1/3)1/2,干燥方程为MR=〔1-(kt)2〕3,干燥速率方程为-dMR/dt=6k2tMR2/3,干燥速率常数为k=Aexp〔-Ev(1+CLL)RT〕;指前因子A=4.0725min-1,界面蒸发活化能Ev=16.9334kJ/mol,经验常数CL=30.3135m-1。     

Facile Synthesis of γ‐In2Se3 Nanoflowers toward High Performance Self‐Powered Broadband γ‐In2Se3/Si Heterojunction Photodiode

An effective colloidal process involving the hot‐injection method is developed to synthesize uniform nanoflowers consisting of 2D γ‐In₂Se₃ nanosheets. By exploiting the narrow direct bandgap and high absorption coefficient in the visible light range of In₂Se₃, a high‐quality γ‐In₂Se₃/Si heterojunction photodiode is fabricated. This photodiode shows a high photoresponse under light illumination, short response/recovery times, and long‐term durability. In addition, the γ‐In₂Se₃/Si heterojunction photodiode is self‐powered and displays a broadband spectral response ranging from UV to IR with a high responsivity and detectivity. These excellent performances make the γ‐In₂Se₃/Si heterojunction very interesting as highly efficient photodetectors.     

花状WO3纳米结构的水热合成及其甲醛气敏研究

采用中温水热法合成了三维花状WO3纳米结构,通过X射线衍射仪(XRD)和扫描电子显微镜(SEM)对样品的物相成分及微观形貌进行了表征。同时基于合成的花状WO3纳米材料制备了气敏元件,测试了其在200℃的最佳工作温度下,对体积分数为40×10^-6的HCHO气体的气敏性能。结果表明,该气敏元件对HCHO气体有优异的选择性及稳定性,同时对HCHO气体灵敏度可达18.57。     

Preparation of single-crystalline nickel nanoflowers and their potential application in sewage treatment

Control of the nucleation and growth rate by H₂O₂ and NaOH provides a facile route to harvest nickel nanoflowers. The choice of NaOH and ethylene glycol (EG) plays the important role in the formation of Ni nanoflowers; while the addition of H₂O₂ is another key role for the preparation of uniform Ni nanoflowers. HRTEM and SEAD patterns show that the Ni nanoflowers are single-crystal and grow along the [200] direction. The magnetic measurement demonstrated that the Ni nanoflowers presented ferromagnetic properties. Furthermore, Ni nanoflowers show potential utilization for the removal of dyes in a wastewater treatment process.     

控制表面氧化法制备超疏水 CuO纳米花膜

采用含有过硫酸钾氧化剂和氢氧化钾的水溶液处理金属铜表面,再经空气中加热后, 在铜表面上得到了一层具有花朵状纳米结构的CuO膜．每朵纳米花由数十个长约2μm、宽约 120nm、厚约12nm的CuO纳米片自组装而成．纳米花膜经氟化处理后表现出超疏水性,接触角达到约158°．文中初步提出了纳米花形态的生长机制,并用Cassie理论对膜的润湿性进行了分析．     

Imidazole‐Grafted Nanogels for the Fabrication of Organic–Inorganic Protein Hybrids

Here, a platform for the development of highly responsive organic–inorganic enzyme hybrids is provided. The approach entails a first step of protein engineering, in which individual enzymes are armored with a porous nanogel decorated with imidazole motifs. In a second step, by mimicking the biomineralization mechanism, the assembly of the imidazole nanogels with CuSO₄ and phosphate salts is triggered. A full characterization of the new composites reveals the first reported example in which the assembly mechanism is triggered by the sum of Cu(II)–imidazole interaction and Cu₃(PO₄)₂ inorganic salt formation. It is demonstrated that the organic component of the hybrids, namely the imidazole‐modified polyacrylamide hydrogel, provides a favorable spatial distribution for the enzyme. This results in enhanced conversion rates, robustness of the composite at low pH values, and a remarkable thermal stability at 65 °C, exhibiting 400% of the activity of the mineralized enzyme lacking the organic constituent. Importantly, unlike in previous works, the protocol applies to the use of a broad range of transition metal cations (including mono‐, di‐, and trivalent cations) to trigger the mineralization mechanism, which eventually broadens the chemical and structural diversity of organic–inorganic protein hybrids.     

三维金属纳米花的合成和应用研究现状

三维金属纳米花有一系列优越的理化性能,由于结构特异,在催化、传感上应用广泛,还可以用于制作微观尺度的器件,引起了人们极大的兴趣。从选择性刻蚀、模板引导、种子生长法和动力学控制等方面,介绍了近期在三维金属纳米花合成领域取得的进展,并简述了这种纳米粒子在催化以及电催化方面的应用。