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1.
A novel metallo-organic chemical vapor deposition (MOCVD) technique has been applied to the preparation of the photocatalytic
titanium dioxide supported on activated carbon. The effects of various condition parameters such as carrier gas flow rate,
source temperature and deposition temperature on the deposition rate were investigated. The maximum deposition rate of 8.2
mg/(g·h) was obtained under conditions of carrier gas flow rate of 400 ml/min, source temperature of 423 K and deposition
temperature of 913 K. The deposition rate followed Arrhenius behavior at temperature of 753 K to 913 K, corresponding to activation
energy E
a of 51.09 kJ/mol. TiO2 existed only in anatase phase when the deposition temperature was 773 K to 973 K. With increase of deposition temperature
from 1073 K to 1273 K, the rutile content sharply increased from 7% to 70%. It was found that a deposition temperature of
773 K and a higher source temperature of 448 K resulted in finely dispersed TiO2 particles, which were mainly in the range of 10–20 nm.
Project (No. 90206007) supported by the National Natural Science Foundation of China 相似文献
2.
采用化学气相沉积的实验方法,以纯Zn粉为锌源,O_2为反应气,N_2为载气,在双管管式炉内制备了多脚结构的纳米ZnO,研究了载气流量对产物形貌和光致发光性能的影响;通过计算流体动力学软件FLUENT对实验条件下管式炉内O_2和Zn蒸汽的浓度分布进行了模拟。实验和模拟结果表明:随着N2流量的增大,O_2浓度减小,产物由钉状多脚结构向针状多脚结构转变;沉积位置处Zn蒸汽的浓度远大于O_2浓度,绿光发射峰主要是由ZnO纳米晶体氧空位引起的,沉积反应主要由O_2控制。 相似文献
3.
Nanosized TiO2 particles,synthesized by microemulsion-mediated method,were characterized by XRD,TEM,EDS and BET.To judge the activity of TiO2 particles,the photocatalytic destruction of phenol in areated suspension was studied.The result shows that the photocatalytic activity of lab-made nanometer anatase TiO2 is comparable to or higher than that of commercial titania perticles.The effects of smoe processing parameters such as TiO2 content,oxygen flow rate,pH value on phenol removal were also investigated.The experimental results indicate that there is an optimum value for the TiO2 content,Sufficient O2 supply is needed, but too high gas flow rate induces large bubbles that eliminate the gas residence time and the gas/liquid contact interface,The pH value of the phenol solutions has a complex effect on the photocatalytic activity of the particles. 相似文献
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章介绍了具有合成H2O2和光催化性能的双功能新型复合电极，并用X－射线衍射，SEM等方法进行了表征，双功能复合电极是将TiO2/C光催化剂负载在具有合成H2O2性能的新型载体上形成的，在光反应器中，复合电极作阴，钌－钛不溶性电极作阳极，低压汞灯作光源，实现了光化学氧化与光催化氧化在同一电极／溶液界面上的联合作用，实验结果表明，复合电极对提高偶氮染料分子活性艳红（K－2BP）的氧化降解速度起到了重要作用，仅反应3min，脱色率可达49％，80min，偶氮染料分子可降解47％。 相似文献
6.
TiO2 fibers were prepared via alternatively introducing water vapor and Ti precursor carried by Ne to an APCVD (chemical vapor deposition under atmospheric pressure) reactor at <200 ℃. Activated carbon fibers (ACFs) were used as templates for deposition and later removed by calcinations. The obtained catalysts were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brtmauer, Emmett and Teller (BET) and X-ray diffraction (XRD) analysisThe pores within TiO2 fibers included micro-range and meso-range, e.g., 7 nm, and the specific surface areas for TiO2 fibers were 141 m2/g and 148 m2/g for samples deposited at 100 ℃ and 200 ℃ (using ACF1700 as template), respectively. The deposition temperature significantly influenced TiO2 morphology. The special advantages of this technique for preparing porous nano-material include no consumption of organic solvent in the process and easy control of deposition conditions and speeds. 相似文献
7.
利用常压MOCVD法在Si及Al2O3衬底上制备了TiO2薄膜.研究了沉积温度和退火温度对TiO2薄膜结构和形貌的影响,以及TiO2薄膜的光学性质.研究发现,沉积温度为600℃时,制备的TiO2薄膜结构为锐钛矿相,薄膜质量较高.TiO2薄膜在1 090℃高温退火后,薄膜结构完全转变为金红相.TiO2薄膜在可见区域有着高达90%以上透射率,在紫外区域有着强烈的吸收. 相似文献
8.
丁慧贤 《福建工程学院学报》2012,(1):60-64
分别采用等离子体与不同催化剂相结合对空气中甲醛的脱除进行实验研究。结果表明,Ag/CeO2催化剂能与等离子体结合高效氧化脱除甲醛,当气体组成为276×10-6HCHO、21%O2,1%H2O,N2为平衡气,空速为16 500 h-1、温度为70℃、压强为一个大气压、输入放电能量密度为108 J.L-1时,99%的甲醛被脱除,86%的甲醛被氧化成CO2。而在同样的条件下,Fe/TiO2和γ-Al2O3催化剂对甲醛的脱除率只为86%和78%。 相似文献
9.
赖华龙 《三明高等专科学校学报》2013,(4):73-77
采用溶胶一凝胶法制备SO4^2-/TiO2催化剂的基体,用不同浓度的硫酸对催化剂基体进行浸渍,考察催化剂性能。选出制备催化剂的硫酸浓度。考察反应温度、甲醇流量对催化剂性能的影响;探讨了催化剂失活的原因。实验结果表明,催化剂S10活性最好;甲醇制烯烃的反应温度为410-430℃,具有98．8％的甲醇转化率和90．65％的乙烯选择性：反应时甲醇的流量为0．05mol·s^-1。 相似文献
10.
We investigated the photocatalytic degradation of dye wastewater by using titanium dioxide （TiO2） coated on a coal cinder. The coal cinder was used as the carrier, with a thin film of TiO2 coated on it by using the sol-gel method. Using the Congo red as the model pollutant for dye wastewater, we studied the decolorization efficiency, and effects of TiO2 film thickness and roasting temperature on the efficiency. We also evaluated the recycling and regeneration of the immobilized TiO2 （TiO2/cinder）. Results show that the decolorization rate of Congo red solution was more than 98% after 2.h treatment when we used TiO2/cinder calcined at 500 ℃ for 2 h and coated four times as the photocatalyst. At the same time, the TiO2/cinder remained high catalytic activity after being reused and regenerated for many times. 相似文献
11.
ZHANG Jia-yuan ZHOU Jie-min 《重庆大学学报(英文版)》2007,6(3):155-160
Steam-reforming is an effective approach for upgrading methane and hydrocarbon of coke-oven gas into CO and H2, but the kinetic behavior needs more study. We investigated the conversion of methane in coke-oven gas by steam reforming process in an electric tubular flow at 14 kPa with temperature varying from 500 °C to 950 °C, and developed a kenetic model for , ignoring the effects of adsorption and diffusion. The optimal dynamic conditions for methane conversion 14 kPa are as follows:the ratio of the amount of water to the amount of methane is from 1.1 to 1.3;the reaction temperature is from 1 223 K to 1 273 K. The methane conversion rate is larger than 95% when the ratio of the amount of water to the amount of methane is 1.2 at a temperature above 1 223 K with the residence time up to 0.75 s. 相似文献
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Decomposition of dimethyl sulfide （DMS） in air was investigated experimentally by using a wire-cylinder dielectric barrier discharge （DBD） reactor at room temperature and atmospheric pressure. A new type of high pulse voltage source with a thyratron switch and a Blumlein pulse-forming network （BPFN） was adopted in our experiments. The maximum power output of the pulse voltage source and the maximum peak voltage were 1 kW and 100 kV, respectively. The important parameters affecting odor decomposition, including peak voltage, pulse frequency, gas flow rate, initial concentration, and humidity, which influenced the removal efficiency, were investigated. The results showed that DMS could be treated effectively and almost a 100% removal efficiency was achieved at the conditions with an initial concentration of 832 mg/m3 and a gas flow rate of 1000 ml/min. Humidity boosts the removal efficiency and improves the energy yield （EY） greatly. The EY of 832 mg/m3 DMS was 2.87 mg/kJ when the relative humidity was above 30%. In the case of DMS removal, the ozone and nitrogen oxides were observed in the exhaust gas. The carbon and sulfur elements of DMS were mainly converted to carbon dioxide, carbon monoxide and sulfur dioxide. Moreover, sulfur was discovered in the reactor. According to the results, the optimization design for the reactor and the matching of high pulse voltage source can be reckoned. 相似文献
13.
建立了气相色谱法测定硬脂酸甲酯催化加氢产物中十八醇含量的方法,从而能够简便地对实验室合成十八醇方法的可行性及有效性进行评估.考察了氢气压强、载气压强、空气压强和色谱柱温度等因素对硬脂酸甲酯催化加氢产物分离分析的影响.选定的最佳分离条件为：氢气压强为0.08 MPa,载气（N2）压强为0.18 MPa,空气压强为0.1 MPa,色谱柱温度为205℃.在这种条件下,十八醇能够在5 min得到分离检测.最终测得实验室采用的两种不同合成条件下产物1和2中十八醇的含量分别为8.7%和30.1%.结果表明,合成条件2优于合成条件1,但仍需改进以提高十八醇的产率. 相似文献
14.
Y^3＋-doped （Bi 1/2 Na 1/2） TiO 3-CaTiO 3-BaTiO 3 （BNCBT） positive temperature coefficient of resistivity （PTCR） ceramics sintered in air atmosphere were investigated in this study. （Bi 1/2 Na 1/2） TiO 3 （BNT） component can remarkably increase the onset temperature T c of PTCR ceramics with the expense of the resistivity R 25 increase. CaTiO 3 （9–27 mol%） component can decrease the resistivity, and adjust the effects of BNT phase on the T c point. For the sample containing 3 mol% CaTiO 3 , T c raises from 122 ℃ to 153 ℃ when only 0.6 mol% BNT added, while for the ones with higher CaTiO 3 content （9–27 mol%）, T c is only increased by a rate of 8–9℃/1.0 mol% BNT. The effects of BNT and CaTiO 3 components on R25/Rmin （negative temperature coefficient effect） are also discussed. 相似文献
15.
在反应温度20℃、紫外光强度700～750μW/cm2、照射时间2h、电磁搅拌时间2h、溶液初始浓度20mg/L的实验条件下,TiO2-膨润土的投加量对光催化降解十二烷基苯磺酸钠(SDBS)的效果有影响:随着TiO2-膨润土投加量由0.01‰增加到0.5‰,SDBS的降解率逐渐提高,当投加量为0.5‰时,光催化降解率最高,达92％,以后随着投加量的增加(从0.5‰到6‰),降解效率反而下降.可见,最佳投加量为0.5‰.在相同实验条件下,投加0.17‰的TiO2(与0.5‰的TiO2 -膨润土中含Ti量相同),SDBS的降解率只有40％.可见,相比TiO2,TiO2-膨润土具有投加量小,降解效率高的优点,更实用. 相似文献
16.
通过溶胶-凝胶法制备了稀土金属离子Y^3＋掺杂的TiO2光催化剂,用XRD进行了分析和表征.以紫外灯为光源,通过对结晶紫的降解反应,研究了掺杂稀土离子钇的TiO2催化活性.结果表明,Y^3＋的掺杂减小了TiO2的粒径,提高了TiO2的光催化活性,反应体系在Y^3＋掺杂量为1.2%,催化剂用量1.5g/L,经500℃煅烧的条件下制备的Y^3＋-TiO2催化下效果最好.降解浓度4.0mg/L结晶紫2小时后,降解率可达90%. 相似文献
17.
汪洋 《浙江大学学报(A卷英文版)》2004,5(8)
The chemisorption properties of N18O adsorption on TiO2(110) surface were investigated by experimental and theoretical methods. The results of temperature programmed desorption (TPD) indicated that the temperatures of the three desorption peaks of the main N2 molecules were at (low) temperature of 230 K, 450 K, and (high) temperature of 980 K. This meant that N18O decomposed and recombined during the process of N2 desorption after N18O was exposed. Analysis of the stable combination and orbital theory calculation of the surface reaction of NO adsorption on the TiO2(110) cluster model showed that there was clear preference for the Ti-NO orientation. 相似文献
18.
介绍断续流动氢化物发生原子荧光测定饮用水中汞的方法,研究了酸度、硼氢化钾浓度、灯电流、载气流速等对测定汞的影响.在优化的分析条件下,检测限为0.02ng/mL,方法应用于水样中汞的测定,样品加标回收率在96.2%~102%之间,相对标准偏差为2.3%.方法具有操作简便、快速、灵敏度高等优点. 相似文献
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INTRODUCTION The adsorption of gas molecules on metals,metal oxides or alloys had been researched widelyto find a solution for the problem of air pollution(Davies and Craig Jr., 2003; Yanagisawa, 1996;Tominaga et al., 1999). NO could be adsorbed onthe particle surface and desorbed as N2 from thesurface by temperature programmed desorption(TPD) (Davies and Craig Jr., 2003; Yanagisawa,1996). The calculation of cluster model was estab-lished with molecular orbital (MO) theory (Ry… 相似文献