超临界乙醇制备TiO2/石墨烯纳米复合材料及其表征

以氧化石墨为载体、钛酸异丙酯为前驱体,利用超临界乙醇的超临界性能和还原性,制得了晶型完善的锐钛矿TiO2/石墨烯纳米复合材料.通过红外光谱（FTIR）、X射线光电子能谱（XPS）对采用Hummers法制得的氧化石墨（GO）进行表征;同时利用透射电子显微镜（TEM）、X射线衍射仪（XRD）对TiO2/石墨烯纳米复合材料进行研究.结果表明：成功制得了氧化石墨（GO）和晶型完善的锐钛矿TiO2/石墨烯纳米复合材料,并且发现二氧化钛在石墨烯纳米片层上呈现为有规则的颗粒,分散均匀,平均粒径为8.24 nm.     

Preparation and catalytic performance of Fe-SBA-15 and FeO x /SBA-15 for toluene combustion

High-surface-area and well-ordered mesopor- ous Fe-incorporated SBA-15 （xFe-SBA-15） and SBA-15- supported FeOx （yFeOx/SBA-15） with the Fe surface den- sity between 0.09 to 1.11 Fe-atom/nm2 have been prepared using the one-step synthesis and incipient wetness impregnation methods, respectively. Physicochemical properties of these materials were characterized by means of numerous techniques, and their catalytic activities for the combustion of toluene were evaluated. It is found that the xFe-SBA-15 and yFeOx/SBA-15 samples possessed rod- or chain-like morphologies. The Fe species were of high dispersion when the Fe surface density was lower than 0.76 Fe-atom/nm2 in xFe-SBA-15 and 0.64 Fe-atom/nm2 in yFeOx/SBA-15. At a similar Fe surface density and space velocity, the xFe-SBA-15 catalysts showed better activity than the yFeOJSBA-15 catalysts, in which the xFe-SBA- 15 catalyst with Fe surface density 0.59 Fe-atom/nm2 performed the best. It is concluded that the good perfor- mance of the xFe-SBA-15 sample with Fe surface density 0.59 Fe-atom/nm2 was associated with its large surface area, high Fe species dispersion, and good low-temperature reducibility.     

Heteroatom-doped graphene for electrochemical energy storage

The increasing energy consumption and envi- ronmental concerns due to burning fossil fuel are key drivers for the development of effective energy storage systems based on innovative materials. Among these materials, graphene has emerged as one of the most promising due to its chemical, electrical, and mechanical properties. Heteroatom doping has been proven as an effective way to tailor the properties of graphene and render its potential use for energy storage devices. In this view, we review the recent developments in the synthesis and applications of heteroatom-doped graphene in supercapacitors and lithium ion batteries.     

Y含量对Ni-20 Cr合金高温抗氧化性能的影响

为了揭示稀土元素Y对Ni-20Cr合金高温抗氧性能的影响,利用非自耗真空电弧炉熔炼4种不同Y含量的Ni-20Cr合金,并对合金进行循环氧化实验。采用X射线衍射仪、扫描电子显微镜等对获得的合金氧化膜进行观察分析。结果表明,Y能提高Ni-20Cr合金的高温抗氧化性能,并且温度越高,作用越明显;添加0.6%Y的Ni-20Cr合金的高温抗氧化性能提升最为明显;添加Y有利于合金选择性氧化膜Cr2 O3的生成,提高氧化膜同基体金属的附着力,降低氧化速率,从而提高合金的高温抗氧化性能。     

Photocatalytic enhancement of Mg-doped ZnO nanocrystals hybridized with reduced graphene oxide sheets

Hybridization of Mg-doped ZnO and reduced graphene oxide(MZO–RGO) were synthesized through one pot reaction process. Crystallization of MZO–RGO upon thermal decomposition of the stearate precursors was investigated by X-ray diffraction technique. XRD studies point toward the particles size with 10–15 nm,which was confirmed by transmittance electronic microscopy,and also indicates that graphene oxide has been directly reduced into its reduced state graphene during the synthesis. Graphene hybridized MZO photocatalyst showed enhanced catalytic activity for the degradation of methylene blue(MB). The degree of photocatalytic activity enhancement strongly depended both on the coverage of graphene on the surface of MZO nanoparticles and the Mg doping concentration. The sample of 2 wt% graphene hybridized 5 at% Mg-doped ZnO showed the highest photocatalytic activity,which remained good photocatalytic activity after nine cycling runs.     

超声法制备纳米氧化镍其性能研究

采用不同方法制备了超级电容器材料NiO纳米球.运用XRD、SEM和TEM对制备的NiO进行了形貌和结构分析.结果表明:在表面活性剂SDBS存在下,超声法制备的NiO为球状结构,粒径为1³nm.在-0.43nm.在-0.4⁰.6V的电位范围内,NiO-US表现出典型的法拉第准电容特性.     

V-Mo-O/γ-Fe2O3磁性催化剂的制备及其催化合成苯甲醛

具有磁性的催化剂在反应与分离过程中具有明显的优势.采用溶胶凝胶法,将磁核引入到催化剂中,制备了V-Mo-O/γ-Fe2O3磁性催化剂,以催化选择氧化甲苯制备苯甲醛为探针反应,对催化剂性能进行了评价;采用现代分析技术,对催化剂结构进行了表征.研究表明,磁核未影响催化剂的基体结构,焙烧温度对催化剂性能影响显著,适宜的焙烧温度为500℃.扫描电镜测试表明,该条件下合成的催化剂呈纤维状结构.通过X-射线衍射分析,催化剂呈现Mo6V9O40和MoO3物相.当催化反应温度为80℃,氧化剂为双氧水,溶剂为冰乙酸时,甲苯在该催化剂上的转化率为34.8%,苯甲醛的选择性为65.9%.     

CoFeMg氧化物纳米晶Fenton-降解亚甲基蓝的反应动力学

采用溶胶-凝胶法制备CoFeMg氧化物纳米晶,并用扫描电子显微镜(SEM)和X射线衍射(XRD)表征样品形貌,考察亚甲基蓝催化剂与H2O2的协同降解作用.采用稳态近似法研究氧化降解亚甲基蓝的动力学过程.结果表明:CoFeMg氧化物纳米晶和H2O2组成的Fenton反应体系可有效降解亚甲基蓝,当催化剂和H2O2的加入量分别为0.8g/L和2mmol/L,初始pH≈7.15时,亚甲基蓝的降解率为95%;与传统的Fenton反应体系相比,溶出铁的质量浓度降低为0.2mg/L;Fenton反应是羟基自由基(·OH)氧化降解有机物的过程,其反应可近似为二级动力学反应.     

[Ni(phen)_3]_2[NiMo_(12)P_8O_(62)H_(18)]单晶材料催化合成阿司匹林的研究

采用水热合成法制备[Ni(phen)3]2[NiMo12P8O62H18]单晶材料,通过考察反应温度、时间及催化剂用量等影响因素,确定了其催化合成阿司匹林的最佳条件为催化剂用量为0.09g,反应温度为80℃,反应时间为15min.表明[Ni(phen)3]2[NiMo12P8O62H18]单晶材料是一种催化合成阿司匹林的绿色、高效催化剂,可以为解决当前硫酸催化合成阿司匹林所产生的低效、污染及高成本的问题提供参考.     

Structural,morphological, and optical properties of tin(Ⅳ) oxide nanoparticles synthesized using Camellia sinensis extract: a green approach

Tin oxide (SnO2) nanoparticles were cost-effectively synthesized using nontoxic chemicals and green tea (Camellia sinensis) extract via a green synthesis method.The structural properties of the obtained nanoparticles were studied using X-ray diffraction,which indicated that the crystallite size was less than 20 nm.The particle size and morphology of the nanoparticles were analyzed using scanning electron microscopy and transmission electron microscopy.The morphological analysis revealed agglomerated spherical nanoparticles with sizes varying from 5 to 30 nm.The optical properties of the nanoparticles' band gap were characterized using diffuse reflectance spectroscopy.The band gap was found to decrease with increasing annealing temperature.The O vacancy defects were analyzed using photoluminescence spectroscopy.The increase in the crystallite size,decreasing band gap,and the increasing intensities of the UV and visible emission peaks indicated that the green-synthesized SnO2 may play future important roles in catalysis and optoelectronic devices.