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1.
以LaFeO3为载体,通过Fe(OH)3对载体进行改性,采用沉积沉淀法制备纳米金催化剂,并对催化剂进行XRD、XPS、AAS和BET测试,考察催化剂的活性和稳定性。结果显示,Fe(OH)3助剂的加入,对催化剂的活性提高不明显,但大大提高了催化剂在反应过程和放置过程中的稳定性。加入助剂的Au/Fe(OH)3/LaFeO3催化剂,由于Fe(OH)3和活性组分的相互作用,减缓了金颗粒的聚集,使得放置近半年的催化剂和新鲜催化剂具有相近的活性和稳定性。 相似文献
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制备条件对Au/AC催化分解臭氧性能的影响 总被引:1,自引:0,他引:1
研究了活性炭负载的金催化剂(Au/AC)对低浓度臭氧的催化分解性能,考察了前驱体溶液pH值、干燥方式、焙烧温度等制备条件对催化剂活性的影响,以及空速对臭氧分解率的影响。结果表明,在金前驱体溶液pH值为10、经微波辐射干燥、200℃氢气还原制备的催化剂,金颗粒在活性炭表面的分布更加均匀,尺寸更小,具有更高的催化活性。在室温、相对湿度45%和空速72000h-1时,对浓度为50mg/m3臭氧的分解率保持在90%以上(在2400min内)。N2吸附-脱附和XPS表征结果表明,活性炭载金催化剂在催化分解臭氧后,比表面积和孔体积略有下降;Au4f的XPS峰虽稍向高能方向移动,但仍保持催化活性;活性炭表面碳含量显著下降而氧含量大幅增加,说明活性炭上负载的Au在自身催化分解臭氧的同时,还起到了促进臭氧与单质碳反应的作用。 相似文献
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高砷难处理金精矿细菌氧化-氰化提金 总被引:1,自引:0,他引:1
通过在高砷金精矿中配入不同比例的低砷碳酸盐型金精矿,使其所含硫、砷及铁等主要矿物成分含量发生变化,研究给矿中铁砷摩尔比对难处理高砷金精矿细菌氧化一氰化浸出效果的影响.结果表明:含砷金精矿中铁砷摩尔比直接影响细菌预氧化的效果,同时也影响细菌的活性和溶液中铁砷摩尔比的变化,给矿中铁砷摩尔比越高,溶液中的铁砷摩尔比也越高,且随着给矿中铁砷摩尔比的增加,溶液中铁砷摩尔比的变化幅度加大,给矿中铁砷摩尔比介于4.6~2之间,有利于细菌预氧化和氰化浸出,铁、砷氧化率分别由6.14%和7.38%提高到89.90%和93.60%,金、银浸出率分别由64.18%和35.93%提高到97.78%和88.83%,较好地改善细菌氧化效果,稳定和优化细菌预氧化过程. 相似文献
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在真空中用蒸发沉积的方法制备了埋藏有Ag或Au纳米粒子的稀土氧化物复合薄膜:Ag—La2O3、Ag—Nd2O3、Ag-Sm2O3、Au—La2O3、Au—Nd2O3和Au—Sm2O3。通过光吸收实验研究,发现这些薄膜都在光波长310-1200nm内出现吸收峰,Ag纳米粒子—稀土氧化物薄膜和Au—Sm2O3薄膜的光吸收峰位置随Ag或Au粒子粒径和数量的增加产生红移;而Au—La2O3和Au-Nd2O3薄膜的光吸收随Au量的增大变为金属性光吸收。分析表明,Ag或Au粒子与稀土氧化物之间的相互作用是影响光吸收峰位置的主要原因。 相似文献
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Ternary Au/Fe2O3-ZnO gas-sensing materials were synthesized by combining co-precipitation and microwave irradiation process. The as-prepared Au/Fe2O3-ZnO was characterized with X-ray diffractometer and scanning electron microscope, and its gas-sensing performance was measured using a gas-sensor analysis system. The results show that the as-prepared products consist of hexagonal wurtzite ZnO, face-centered cubic gold nanoparticles and orthorhombic Fe2O3 crystallines. The Au/Fe2O3-ZnO based sensor has a very high selectivity to ethanol and acetone, and also has high sensitivity (154) at a low working temperature (270 °C) and an extremely fast response (1 s) against acetone. It is found that the selectivity can be adjusted by Fe2O3 content added in the ternary materials. It possesses a worth looking forward prospect to practical applications in acetone detecting and administrating field. 相似文献
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阐述了石油亚砜(PSO)选择性萃取分离Pd的基本原理,并以此为基础研究了用DBC萃Au、PSO萃Pd及N235萃Pt,从金川蒸馏Os、Ru之后的脱胶液中萃取分离金、钯、铂的工艺过程 相似文献
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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. 相似文献
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在超声场作用下,以氯金酸为前驱物,经柠檬酸钠和单宁酸还原,在云母基底上组装分散均匀的金纳米粒子单层膜。利用扫描探针显微镜、扫描电子显微镜和X射线衍射等技术对制备的金胶体进行表征。结果表明:超声场分布和超声功率对金纳米粒子形貌影响较大,驻波场下制备的金粒子为纺锤形,而且随超声波功率的增大,纺锤形金粒子的平均长径比减小;而在扩散场中得到单分散的球形金纳米颗粒,XRD和SEM测试表明金的平均晶粒尺寸为25 nm。金纳米粒子在处理前后的云母表面均能组装成膜,但在处理后的云母表面覆盖度更大 相似文献
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在超声场作用下,以氯金酸为前驱物,PVP为保护剂,经KBH4还原,制备了分散均匀的金胶体。利用X射线衍射、透射电子显微镜和分光光度技术等对制备的金胶体进行了表征。结果表明:金纳米粒子为25nm左右的球形或椭球形。还原剂用量对金胶体的最大吸收峰位影响较大,当KBH4用量小于1mL时,最大吸收波长为530nm,吸收峰较低而宽;KBH4加入量超过2mL时,最大吸收峰明显蓝移,在512~514nm,最大吸收峰增强,但峰变宽。继续增加KBH4用量超过5mL,吸光度曲线基本不变,KBH4用量超过8mL后最大吸收峰在510nm左右,但吸光度较高,且峰形尖而窄,单分散性好。超声场分布、超声功率和温度使金胶体的最大吸收峰变小,最大吸收峰位在510nm左右。 相似文献
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《Synthetic Metals》2006,156(1):32-37
The electronic structures of pentacene and C60 interfaces were investigated using ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS). The magnitudes of measured interface dipole were 0.11 eV and 0.07 eV for the C60 deposited on pentacene (C60/pentacene) and the pentacene deposited on C60 (pentacene/C60), respectively. The obtained C 1s spectra on these samples show that no significant chemical bonds at the interface. The offsets of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) at the C60-pentacene interface were 1.29 eV and 0.89 eV for C60/pentacene/Au, while for pentacene/C60/Au they were 1.5 eV and 1.1 eV. In this paper we present the complete energy level diagrams of C60/pentacene/Au and pentacene/C60/Au. 相似文献
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采用拉伸试验、硬度测试和光学显微分析等手段研究了Au-Ti足金的强化机理。结果表明,Au-Ti足金的强化方式主要是细晶强化、加工硬化和时效强化,且其力学性能优于标准的Au917饰品用金合金Au917Ag55Cu28,Au917Ag32Cu51。并且,Au-Ti足金的冷加工性能优于千足金,这是由于其固溶态硬度、强度高,延性好。 相似文献
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Au nanorods were prepared by a seeding growth approach and used in fabricating the nanorod-enhancing glucose biosensor. The high affinity of chitosan for Au nanorods associated with its amino groups resulted in the formation of a layer of Au nanorods on the surface of Au electrode. It served as an intermediator to retain high efficient and stable immobilization of the enzyme. The performance of biosensors was investigated by cyclic voltammetry (CV), in the presence of artificial redox mediator, ferrocenecarboxaldehyde. The biosensor had a fast response to glucose, and the response time was less than 10 s. The results indicated that the gold nanorods could enhance the current response to glucose. The detection limits of glucose can reach 10 mM, and the Michaelis-Menten constant Kappm 13.62 mM. 相似文献
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《Acta Materialia》2004,52(8):2133-2146
We examine creep of thin film Au on curved bimaterial Au/Si microcantilevers. Time-dependent inelastic strains in the Au film lead to gradual changes in the microcantilever curvature over time. Curvature–temperature–time experiments are used to examine the effects of hold temperature and maximum annealing temperature on the inelastic response of the Au films. Experiments reveal inelastic strains in the Au films due to creep, recovery, and microstructural coarsening. At moderate hold temperatures, 30 °C < T < 175 °C, inelasticity in the Au films is observed to be a competition between creep and recovery. Creep strains are driven by tensile stresses in the film and serve to decrease the microcantilever curvature towards the equilibrium curvature of the underlying Si beam. Strains due to recovery of the metastable Au cause contraction of the film and the development of intrinsic tensile film stresses. At higher hold temperatures T>175 °C, the response of the film is dominated by microstructural coarsening which leads to an expansion of the film, the development of intrinsic compressive film stresses, and hillock formation. The recovery and microstructural coarsening both lead to ‘anomalous’ changes in microcantilever curvature since the curvature gradually increases or decreases away from the equilibrium curvature of the underlying Si. The inelastic behavior of the Au film is shown to depend on annealing temperature through changes in initial film stress after thermo-elastic cooling and degree of recovery. 相似文献
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V. Rajagopal Reddy M. Siva Pratap ReddyB. Prasanna Lakshmi A. Ashok Kumar 《Journal of Alloys and Compounds》2011,509(31):8001-8007
In the present work, we have investigated the current-voltage (I-V) and capacitance-voltage (C-V) characteristics of Au/SiO2/n-GaN metal-insulator-semiconductor (MIS) Schottky diode and compared with Au/n-GaN metal-semiconductor (MS) Schottky diode. Calculations showed that the Schottky barrier height and ideality factor of the MS Schottky diode is 0.79 eV (I-V), 0.87 eV (C-V) and 1.45, respectively. It is observed that the Schottky barrier height increases to 0.86 eV (I-V), 0.99 eV (C-V) and ideality factor deceases to 1.3 for MIS diode. For the MS diode, the calculated doping concentration is 4.17 × 1017 cm−3. However, in the case of the MIS Schottky diode, the decrease in doping concentration is observed and the respective value is 2.08 × 1017 cm−3. The obtained carrier concentration of the MIS diode is reduced about 50% when compared to the MS diode. The interface state density as determined by Terman's method is found to be 3.79 × 1012 and 3.41 × 1010 cm−2 eV−1 for the MS and MIS Schottky diodes, respectively. The calculated interface densities are 2.47 × 1011 cm−2 eV−1, 3.35 × 1011 cm−2 eV−1 and 3.5 × 1011 cm−2 eV−1 for the sweep rates of 300, 450 and 600 mV/s from MOS C-V measurements for the MIS Schottky diode. The interface state density calculated from Terman's method is found to be increased with sweep rate. From the C-V measurement, it is noted that the decrease in the carrier concentration in MIS diodes as compared to MS diode may be due to the presence of oxide interfacial layer. DLTS measurements have also been performed on MIS Schottky diode and discussed. 相似文献
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采用熔融的共晶锡铅钎料熔滴与Au/Ni/Cu焊盘瞬时接触液固反应形成钎料凸点,随后进行再流焊及老化.对这一过程中的钎料/焊盘界面金属间化合物组织的演化,尤其是Au-Sn化合物的形成及分布进行了研究.结果表明,钎料熔滴与焊盘液固反应形成了Au-Sn界面化合物,铜层未完全反应.在随后的再流焊过程中,界面处的铜层完全消耗掉,镍层与钎料反应形成Ni3Sn4界面组织;针状的AuSn4化合物分布于钎料基体中.老化条件下分布于钎料基体中的AuSn4重新在界面沉积,在Ni3Sn4层上形成(AuxNi1-x)Sn4层.(AuxNi1-x)Sn4在界面的沉积遵循分解扩散机制,并促进富铅相的形成.钎料与焊盘反应过程中Au-Sn化合物的演化及分布直接影响钎料与焊盘的连接强度. 相似文献
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L.P. Salamakha O.L. Sologub A.P. Gonalves S.I. Mudryi V.B. Kapustianyk M. Almeida 《Journal of Alloys and Compounds》2007,430(1-2):175-178
A new ternary compound Ce(Au,Sb)2, with a homogeneity range has been observed from X-ray powder diffraction of as cast alloys, a = 4.743–4.712 Å, c = 3.567–3.768 Å. Its crystal structure was investigated by X-ray diffraction from Ce(Au1−xSbx)2 (x = 0.266) single crystal: CAD-4 automatic diffractometer, Mo K radiation, a = 4.7256(6) Å, c = 3.6711(6) Å, P6/mmm space group, V = 70.997(17) Å3, Z = 1, ρ = 10.732 Mg/m3, μ = 76.369 mm−1, R1 = 0.0415, wR2 = 0.0793 for 99 reflections with I > 2σ(I0). The coordination polyhedron of X (X = 0.734Au + 0.266Sb) atom is a full-capped trigonal prism [XCe6X3X2]. Ce atom is coordinated by 14 atoms: [CeX12Ce2]. The compound is isotypic with UHg2 structure, a deformation derivative of AlB2 structure type. It forms isostructural compounds with La and Pr. 相似文献