Synthesis of bamboo-like carbon nanotubes by ethanol catalytic combustion technique

Bamboo-like carbon nanotubes were synthesized by ethanol catalytic combustion （ECC） technique with combustion method. Copper plate was employed as substrate, ethanol as carbon source, and iron chloride as catalyst precursor. The as-grown black powder was characterized by means of scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The results show that the thinner bamboo-like carbon nanotubes have a relatively good structure that the compartment layers are more regular, while the thicker carbon nanotubes have a relatively irregular bamboo-like structure; the proposed method is simple to synthesize bamboo-like carbon nanotubes and has some advantages, such as flexible synthesis conditions, simple setup, and environment-friendly.     

Preparation of carbon nanotubes by ethanol catalytic combustion technique using nickel salt as catalyst precursor

A simple growth technique of carbon nanotubes （CNTs） by combustion of ethanol was developed. In the experiment, copper plate was employed as substrate, nickel nitrate （Ni（NO3）2） and nickel chloride （NiCl2） as catalyst precursor, and ethanol as carbon source. The cleaned copper substrate was dipped into catalyst precursor solution for mounting catalyst precursor particles. The dip-coated substrate was then placed into ethanol flame for about 10 min after drying. The black wool-like production grown on copper plate was obtained. This route is called an ethanol catalytic combustion（ECC） process. The black powders were characterized by means of scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, energy dispersive X-ray spectrometer（EDS） and Raman spectroscopy. The results show that the techique is much simpler and more economical to meet the future broader applications.     

Synthesis of Y-junction carbon nanofibres by ethanol catalytic combustion technique

Y-shaped structure was synthesized by ethanol catalytic combustion（ECC） technique on the copper plate substrate, without directly seeding catalyst into the flame. The as-grown Y-junction carbon nanofibres were investigated by transmission electron microscopy （TEM）. The very common laboratory ethanol burner was used for synthesizing carbon nanofibres. Two kinds of the catalyst precursor, which are iron nitrate （Fe（NO3）3） and nickel nitrate （Ni（NO3）2）, were respectively employed to assist the formation of Y-junction carbon nanofibres. TEM analysis confirm the formation of Y-junction in the coiled and noncoiled carbon nanofibres. The type of the catalyst is found to be crucial to grow different Y-junction carbon nanofibres. Different Y-shaped structure may possess different mechanical and electronic properties. These three-terminal nanofibres provide the nanoelectronics community with a novel material for the development of molecular-scale electronic devices.     

Preparation and characterization of La0.8Cu0.2MnO(3±δ) perovskite-type catalyst for methane combustion

La0.8 Cu0.2 MnO(3±δ) perovskite-type catalyst for methane combustion prepared through sol-gel process was characterized by X-ray Diffractometry(XRD), X-ray Photoelectron Spectroscopy(XPS) and Scanning Electron Microscopy(SEM). XPS analyses reveal that the surface characteristics of the catalyst are changed. The lattice defects and oxygen vacancies on the catalyst surface are enhanced due to a part of La3+ being substituted by Cu2+.Temperature-programmed-desorption(TPD) and temperature-programmed-reduction(TPR) analyses were carried out to study the catalytic behavior. It is found that there are two O2-desorption peaks at 350 ℃ and 650 ℃ in the TPD pattern, and two CH4-consumption peaks at 420 ℃ and 750 ℃ in the TPR patterns respectively, which indicates that the two kinds of oxygen species, so-called α and β oxygen, can react with the methane during catalytic combustion process. The catalytic activity tests were performed in a fixed-bed reactor, and the results show that the T1/2 at which the conversion of methane attains 50 % of La0.8 Cu0.2 MnO(3±δ) is lower by 55 ℃ than that of LaMnO3.This indicates that the catalytic activity of La0.8 Cu0. 2 MnO(3±δ) is increased with partial substitution of Cu2+ for La3+.     

钙钛矿催化材料La1-xCexCoO3+δ的制备、表征及甲烷燃烧催化性质

采用柠檬酸发泡法制备了钙钛矿LaCoO3催化材料;研究了Ce对La进行掺杂替代对催化材料性能的影响;通过BET、XRD、SEM等手段对催化材料进行了物性表征;以甲烷完全燃烧为目标反应,研究了钙钛矿La1-xCexCoO3 δ的催化性能.结果表明:铈掺杂对材料晶相有较大影响,当掺杂量x小于0.3时,粉体晶型基本不变,而当掺杂量达到0.5时,有明显CO3O4晶相出现,LaCoO3钙钛矿晶相完整性遭到破坏,当掺杂量大于0.7时,钙钛矿晶相大大弱化甚至消失;LaCoO3是一种性能优良的甲烷燃烧催化材料,Ce的掺杂替代对催化材料活性有明显影响,并增强了催化材料的高温稳定性能,铈最佳掺杂量为0.3;前驱体经700℃焙烧形成了较为完整的钙钛矿晶型,经800℃焙烧后,催化材料最高活性为:t10%=390℃,t90%=603℃.     

Catalytic activity of Au/Fe-PILC and Au/Fe-oxide catalysts for catalytic combustion of formaldehyde

Iron polymeric hydroxygroups pillared clays （Fe-PILC） were prepared by Na^＋-montmorillonite with iron pillaring agent. 2.01Au/Fe-PILC catalyst was obtained by deposited-precipitation （DP） method. 2.52Au/Fe-oxide catalyst was prepared by co-precipitation method. The catalytic activity of these catalysts was measured by catalytic combustion of formaldehyde. The catalyst of 2.01Au/Fe-PILC exhibits the high catalytic activity. The catalytic combustion reaction of formaldehyde proceeds at considerable rates at 20 ℃ and complete burn-off of formaldehyde is achieved at 120 ℃. The structure of catalysts, the valence state of gold and the size of gold particles were investigated by means of X-ray powder diffractometry, X-ray photoelectron spectroscopy and transmission electron microscopy. The results show that gold atoms with partially positive charge exist in the catalyst and play an important role in the catalytic activity. In addition, nano-sized, well-dispersed gold particles and good adsorption properties of support are necessary to obtain high activity Au catalysts for catalytic combustion of formaldehyde.     

乙醇火焰中生长一维碳纳米材料的研究进展

综述乙醇火焰中生长碳纳米管和碳纳米纤维等一维碳纳米材料的方法,及其微观结构、生长机理和物理化学性能。结合SEM和TEM等表征手段,重点述评了一维碳纳米材料的阵列控制生长和纳米同质异构结的制备。结果表明:乙醇火焰是制备碳纳米管和碳纳米纤维的有效方法,具有燃料储存安全和燃烧设备简单等特点。展望了乙醇火焰中生长一维碳纳米材料的发展趋势,并认为其特殊的微结构特征和奇异的物理化学性能以及在微纳米器件上的应用开发将是未来一段时间的研究热点。     

Synthesis of Au-catalyzed silicon nanowires by hydrogen radical-assisted deposition method

Silicon nanowires (SiNWs) catalyzed by gold (Au) nanoparticles were synthesized from silane gas by the hydrogen radical-assisted deposition method. The gold particles used as catalyst were fabricated from an evaporated Au film on a glass substrate by hydrogen radical treatment and the structural properties were estimated. Subsequently, large quantities of SiNWs with various crystal diffraction phases were synthesized on this substrate. The SiNWs were whisker-like and were typically several microns long with diameters of tens of nanometers near the bottom and several nanometers at the top. Hydrogen radical treatments for fabricating catalyst particles and the subsequent deposition method for synthesizing SiNWs are proposed and discussed.     

Leaching of chromite ore in concentrated KOH by catalytic oxidation using CuO as catalyst

CuO was used as a catalyst in the concentrated KOH solution to enhance the leaching of chromium from the chromite ore. The impacts of temperature, KOH-to-chromite ore mass ratio, CuO-to-chromite ore mass ratio, and gas flow rate on the chromium leaching rate were investigated. The results indicated that CuO played an important role in improving the chromium leaching rate. The leaching rate reached 98% after leaching for 6 h when CuO was applied, whereas it was only 60.8% without CuO under the same reaction conditions: temperature 230 °C, KOH-to-ore mass ratio 6:1, stirring speed 700 r/min, gas flow rate 1 L/min. According to the kinetics study, the catalytic oxidation was controlled by surface chemical reaction and the activation energy was calculated to be 15.79 kJ/mol when the temperature was above 230 °C. In contrast, without CuO, the rate-determining step was external diffusion and the apparent activation energy was 38.01 kJ/mol.     

Nanoscale Ni-B amorphous alloy catalyst supported on carbon nanotubes

Heat treatment of carbon nanotubes （CNTs） was carried out under ammonia atmosphere and then CNTs were modified by Triton x-100 （CNTs-T）. Ni-B amorphous alloy catalysts supported on CNTs and CNTs-T were prepared by impregnation-chemical reduction method. The catalysts were characterized by TEM, ICP, XRD, BET and CO chemisorption, and studied in the acetylene selective hydrogenation. The results show that homogeneous Ni-B amorphous particles with mean size about 10 nm are successfully prepared on CNTs-T. Compared with Ni-B/CNTs, nickel loading of Ni-B/CNTs-T is increased by about 14.6%. Furthermore, the activity and selectivity of Ni-B/CNTs-T are much higher than those of Ni-B/CNTs in the acetylene selective hydrogenation under comparative condition.     

Study on hexaaluminate MnLaAl11O19-δcatalyst for catalytic combustive reaction of dimethyl ether as a new fuel

Study on catalytic combustive reaction of dimethyl ether as a new fuel was presented. Hexaaluminate catalysts were used to reduce ignition temperature so that dimethyl ether completely combusted at low temperature. Hexaaluminate catalysts MnLaAl11O19-δ were prepared by reverse microemulsion method. Crystalline phase and structure of the catalyst were analysed by means of TG-DTA, XRD and BET. The results show that the hexaalunminate is of magnetoplumbite structure when La is taken as mirror plane cation. Hexaalunminate phase is formed slowly via 1050 ℃ calcined for 4 h and it can keep hexaaluminate phase and high surface area of 48 m2·g-1 even calcined at 1200 ℃ for 2h. Catalytic activity of MnLaAl11O19-δ was tested in combustion reaction of dimethyl ether. It shows that hexaaluminate is of high activity with T 10% at 170 ℃ and almost 100% conversion at 370 ℃.     

还原剂浓度对原位沉积铂纳米线催化层结构和性能的影响

采用湿化学法研究还原剂甲酸浓度对铂纳米线(Pt-NWs)长度和分布的影响以及Pt-NWs对单电池的电化学性能和耐久性的影响。结果表明:随着还原剂浓度的增加(0.075～0.590 mol/L),Pt-NWs的长度先增加后减小,在碳基体层厚度方向上Pt分布从均匀到逐渐聚集在表层,呈现明显梯度特征。当还原剂浓度为0.372 mol/L时,可获得在整个碳基体层厚度方向上分布的Pt-NWs团簇,与商用的催化剂(JMPt/C)相比,在0.6V时,电流密度提高11.3%,最大功率密度提高12.5%,这主要归于Pt-NWs的一维结构、在催化层中的梯度分布以及高Pt利用率。通过加速耐久性测试,Pt-NWs/C的最大功率密度和电化学活性表面积比JM Pt/C的衰减缓慢,说明Pt-NWs/C具有更好的稳定性。     

Catalytic performance and kinetics of Au/γ-Al_2O_3 catalysts for low-temperature combustion of light alcohols

Au/γ-Al2O3 catalysts were prepared by deposition-precipitation method for the catalytic combustion of low concentration alcohol streams(methanol,ethanol,iso-propanol and n-propanol).The catalysts were characterized by X-ray photoelectron spectroscopy(XPS),X-ray diffractometry(XRD) and energy dispersive X-ray micro analysis(EDS) techniques.The XPS results showed that there was only Au0 on the surface of catalysts.The XRD patterns showed that Au was presumably highly dispersed over γ-Al2O3.The temperatures for complete conversion of methanol,ethanol,iso-propanol and n-propanol with concentration of 2.0 g/m3 were 60,155,170 and 137 ℃,respectively,but they were completely mineralized into CO2 and H2O at 60,220,260 and 217 ℃ respectively over the optimized catalyst.The activity of the catalyst was stable in 130 h.The kinetics for the catalytic methanol elimination followed quasi-first order reaction expressed as r=0.652 8c0+0.084 2.The value of apparent activation energy is 54.7 kJ/mol in the range of reaction temperature.     

超重力燃烧熔渗钨铜合金绝热温度计算及其显微组织

根据燃烧合成体系绝热温度的热力学基本理论,通过计算机编程,对CuO/Al铝热剂体系的绝热温度进行了数值计算.结果表明,在考虑产物Cu的汽化焓情况下,体系绝热温度为2846 K(Cu的沸点温度),同时还有52.9 at％的Cu产物以气相形式存在,而该体系中钨粉添加量超过30 mass％时,绝热温度低于1800 K而不能自蔓延燃烧.采用超重力燃烧熔渗方法制备出组织致密,钨颗粒体积分数呈梯度分布(沿超重力方向70％～80 at％)的钨铜合金.进一步检测结果表明,该方法与传统烧结方法制备的钨铜合金其相结构及显微组织形貌相同,并对其成型机制进行了初步分析讨论.     

Effects of filler and ethanol on mechanical properties of glass-like carbon

The effects of filler and ethanol on the mechanical properties of glass-like carbon were studied. The specific gravities of glass-like carbons with the filler were higher than those of alcohol added glass-like carbons due to the formation of pores and bubbles as the alcohol was vaporized in the curing and polymerization stages. The ethanol added glass-like carbon samples also had lower bending strength than the filler added glass-like carbon samples after carbonization; a contrary result was observed after heat treatment at 2600°C. This was due to the pores that were made with ethanol which plays the role of pore former during carbonization. The fabricated glass-like carbons are quite brittle material. The shore hardness of the glass-like carbon was observed not to be affected by the addition of filler or ethanol, but increased a lot after carbonization.     

热分解法制备Pd-Sn催化剂的结构与性能

利用热分解法制备Ti/Pd₂Sn+PdO和Ti/Pd电极。采用高分辨率透射电子显微镜（HRTEM）、能量散射谱仪（EDS）、选区电子衍射（SAED）对催化剂进行表征。利用循环伏安法和计时电流法研究了所制备催化剂的催化活性和稳定性。结果表明,Ti/Pd₂Sn+PdO电极比Ti/Pd电极具有更高的甲酸催化活性（约2.4倍）。Ti/Pd₂Sn+PdO电极在0.3 V（vs SCE）下测试500 s后电流密度仅衰减25%,具有比Ti/Pd电极更好的稳定性。Ti/Pd₂Sn+PdO电极显著提高了催化活性和稳定性为Pd基直接甲酸燃料电池催化剂的应用提供可行方案。     

醒脑静注射液对乙醇所致记忆功能障碍的影响

目的: 观察醒脑静注射液(Xnji) 对乙醇所致记忆障碍的改善作用。方法: 乙醇一次给大鼠和小鼠灌服和连续灌服造成学习记忆功能障碍, 学习记忆的测试采用Morris 水迷宫法, 电迷宫法和避暗法。结果: Xnji 1.4, 0.7 ml·kg^-1可预防一次性灌服乙醇所致的大鼠空间辨别障碍;Xnji 1, 2 ml·kg^-1 可治疗连续灌服乙醇所致的小鼠空间辨别障碍和记忆获得障碍。结论: Xnji 可防治急、慢性乙醇中毒所致的学习记忆功能减退。     

Synthesis of La-hexaaluminate catalyst for methane combustion by a reverse SDS microemulsion

La-hexaaluminate catalyst for methane catalytic combustion was synthesized by a reverse microemulsion.Pseudo-ternary phase diagrams of a quaternary microemulsion system of sodium dodecyl sulfate(SDS),n-pentanol,n-octane,and water(or Al(NO3)3 solution) were presented.The effects of alcohol chain length,cosurfactant-to-surfactant ratio,and salt concentration on the formation and stability of the microemulsion system were studied.The phenomenon that the conductivity changed with water supported the phase behav...