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51.
氮掺杂金刚石(N-D)是最重要的碳基电子材料之一,由于氮相关色心的存在,其具有许多有趣而独特的物理特征。文章中研究了等离子体化学气相沉积法生长的N-D样品的太赫兹(THz)磁光特性。应用偏振THz时域光谱(THz TDS)技术,在0~8 T磁场和80 K温度条件下,测量了N-D样品在法拉第几何结构下的THz透射光谱,得到了N-D材料的法拉第旋转角和椭偏率、复横向(或霍尔)磁光电导率以及复左、右旋介电常数随磁场的变化规律。结果表明,N-D材料具有优良的THz磁光法拉第旋光效应,可应用于THz旋光器件。 相似文献
52.
采取从某一温度(600~1000℃)开始缓慢升温至高温(1150℃)并保温若干时间的方法,使得直拉Si片中大于起始温度对应的氧沉淀临界尺寸的那一部分原生氧沉淀得以长大,然后通过傅里叶红外光谱测量氧浓度变化以及利用扫描红外显微术测量氧沉淀密度.通过这样的方法,定性地研究了300mm掺N直拉Si片的原生氧沉淀的径向分布.研究表明:氧沉淀异常区域(称为P区)的原生氧沉淀密度显著高于空位型缺陷区域(称为V区);此外,V区中的原生氧沉淀的尺寸分布是不连续的,表现为高温下形成的大尺寸原生氧沉淀和低温下形成的小尺寸氧沉淀,而P区中的原生氧沉淀的尺寸分布则是连续的.我们从直拉Si晶体生长过程中原生氧沉淀的形成机制出发,对上述结果做了定性的解释. 相似文献
53.
Jiamin Xiao Shishi Zhang Yanyan Sun Xuetao Liu Guangling He Heng Liu Javid Khan Yanlin Zhu Yaqiong Su Shuangyin Wang Lei Han 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(12):2206472
The development of highly efficient and cost-effective hydrogen evolution reaction (HER) catalysts is highly desirable to efficiently promote the HER process, especially under alkaline condition. Herein, a polyoxometalates-organic-complex-induced carbonization method is developed to construct MoO2/Mo3P/Mo2C triple-interface heterojunction encapsulated into nitrogen-doped carbon with urchin-like structure using ammonium phosphomolybdate and dopamine. Furthermore, the mass ratio of dopamine and ammonium phosphomolybdate is found critical for the successful formation of such triple-interface heterojunction. Theoretical calculation results demonstrate that such triple-interface heterojunctions possess thermodynamically favorable water dissociation Gibbs free energy (ΔGH2O) of -1.28 eV and hydrogen adsorption Gibbs free energy (ΔGH*) of -0.41 eV due to the synergistic effect of Mo2C and Mo3P as water dissociation site and H* adsorption/desorption sites during the HER process in comparison to the corresponding single components. Notably, the optimal heterostructures exhibit the highest HER activity with the low overpotential of 69 mV at the current density of 10 mA cm−2 and a small Tafel slope of 60.4 mV dec−1 as well as good long-term stability for 125 h. Such remarkable results have been theoretically and experimentally proven to be due to the synergistic effect between the unique heterostructures and the encapsulated nitrogen-doped carbon. 相似文献
54.
A Co-based metal-organic framework (Co-MOF) with a unique three-dimensional starfish-like nanostructure was successfully synthesized using a simple ultrasonic method.After subsequent carbonization and oxidation,a nanocomposite of nitrogen-doped carbon with a Co3O4 coating (Co3O4@N-C) with a porous starfish-like nanostructure was obtained.The final hybrid exhibited excellent lithium storage performance when evaluated as an anode material in a lithiumion battery.A remarkable and stable discharge capacity of 795 mAh·g-1 was maintained at 0.5 A·g-1 after 300 cycles.Excellent rate capability was also obtained.In addition,a full Co3O4@N-C/LiFePO4 battery displayed stable capacity retention of 95% after 100 cycles.This excellent lithium storage performance is attributed to the unique porous starfish-like structure,which effectively buffers the volume expansion that occurs during Li+ insertion/deinsertion.Meanwhile,the nitrogendoped carbon coating enhances the electrical conductivity and provides a buffer layer to accommodate the volume change and accelerate the formation of a stable solid electrolyte interface layer. 相似文献
55.
以低聚酰亚胺为氮源前驱体、交联酚醛树脂为碳源、嵌段共聚物为软模板剂,通过相分离自组装、交联和高温锻烧处理制备了新型高规整含氮介孔碳材料,并用FT-IR、SEM、TEM、热重分析和小角X光散射等测试方法表征介孔碳材料的组成与结构.结果表明,处理温度达350℃时嵌段共聚物模板可被成功移除,进而形成多孔结构;温度达600℃时体系完全碳化,可得到高规整的多孔含氮碳材料.通过调节体系中氮源、碳源及模板剂的相对比例可实现形貌由立方结构向柱状和层状结构的过渡,进而实现对含氮介孔材料形貌的有效调控. 相似文献
56.
Sergio A Aguila David Shimomoto Franscisco Ipinza Zaira I Bedolla-Valdez José Romo-Herrera Oscar E Contreras Mario H Farías Gabriel Alonso-Nú?ez 《Science and Technology of Advanced Materials》2015,16(5)
The use of nanomaterials allows the design of ultrasensitive biosensors with advantages in the detection of organic molecules. Catechol and catechin are molecules that occur naturally in fruits, and their presence in products like dyes and wines affects quality standards. In this study, catechol and catechin were measured at the nanoscale by means of cyclic voltammetry. The oxidation of Coriolopsis gallica laccase immobilized on nitrogen-doped multiwalled carbon nanotubes (Lac/CNx-MWCNT) and on graphene oxide (Lac/GO) was used to measure the concentrations of catechol and catechin. Nitrogen-doped multiwalled carbon nanotubes (CNx-MWCNT) were synthesized by spray pyrolysis and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and x-ray photoelectron spectroscopy (XPS). Covalently bonded hybrids with laccase (Lac/CNx-MWCNT and Lac/GO) were generated. Catalytic activity of free enzymes determined with syringaldazine yielded 14 584 UmL−1. With Lac/CNx-MWCNT at concentrations of 6.4 mmol L−1 activity was 9326 U mL−1, while enzyme activity measured with Lac/GO at concentration of 6.4 mmol L−1 was 9 234 U mL−1. The Lac/CNx-MWCNT hybrid showed higher stability than Lac/GO at different ethyl alcohol concentrations. The Lac/CNx-MWCNT hybrid can measure concentrations, not previously reported, as low as 1 × 10−8 mol L−1 by measuring the electric current responses. 相似文献
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59.
以硝酸铋和六次甲基四胺为原料,采用沉淀法合成了不同氮掺杂量的Bi2O3(N-Bi2O3)粉体,并采用XRD、FT-IR、XPS、UV-Vis、PL手段对其晶相结构和光谱特征等进行了表征.研究结果表明,未掺杂Bi2O3为单斜相α-Bi2O3,氮掺杂Bi2O3则为四方相β-Bi2O3和Bi5O7NO3组成的混晶,氮原子替代了Bi2O3晶格中部分氧原子,形成了Bi N键而稳定存在.氮掺杂能促进β-Bi2O3的生成.与未掺杂Bi2O3粉体相比,氮掺杂样品的吸收带边发生了明显红移,荧光强度明显减弱.甲基橙在可见光下的降解实验表明,氮掺杂Bi2O3具有良好的可见光催化活性. 相似文献
60.
采用射频磁控溅射法在普通MBT直丝弓金属托槽表面制备了锐钛矿相掺氮TiO2-xNx薄膜,通过MTT比色法、细胞形态学观察、扫描电镜及荧光染色法评价薄膜托槽的细胞学性能。结果表明,掺氮TiO2-xNx薄膜托槽的细胞毒性为0级,与对照组相比,薄膜托槽组细胞的相对增殖率差异无统计学意义(P0.05);扫描电镜图像显示细胞在薄膜托槽表面贴壁生长良好;荧光显微镜观察显示粘附在材料表面的细胞其细胞核呈亮黄绿色荧光,细胞质呈绿色荧光,细胞生长良好。由此证明掺氮TiO2-xNx薄膜托槽具有良好的细胞相容性。 相似文献