Kinetics of the methanation of carbon dioxide over a supported Ni-La2O3 catalyst

The kinetics of the methanation of carbon dioxide was investigated using an alumina supported Ni-La₂O₂ catalyst in a differential and integral reactor. In the differential reactor the molar ratio of H₂ to CO₂ was varied from 0.6 to 30. In the integral reactor the rates were measured with up to 90% conversion. Both reactor tests were carried out at temperatures between 513 and 593 K. The experimental results were described by a Langmuir-Hinshelwood type equation. The kinetics can be explained by assuming equilibrium of dissociative carbon dioxide and hydrogen adsorption, and assuming hydrogenation of surface carbon as the rate determining step.     

High PVC film‐forming composite latex particles via miniemulsification,part 1: Preparation

Miniemulsification technology was used to encapsulate TiO₂ particles inside a styrene/n‐butyl acrylate copolymer with high loading levels (11 to 70% PVC (pigment volume concentration)). In this approach, a St/BA copolymer dissolved in toluene in the presence of a costabilizer (hexadecane) was mixed with a dispersion of TiO₂ particles in toluene and sonified, and then emulsified in an aqueous surfactant solution by sonification. The effect of sonification time on both the dispersibility of the TiO₂ particles in the presence of the copolymer and hexadecane and on the encapsulated particle size was investigated. Particle size analysis by dynamic light scattering showed that these composite latexes are quite stable. It was also found that as the TiO₂ loading increased from 11 to 43% PVC, the particle size of the TiO₂ dispersion decreased while the polymer‐encapsulated TiO₂ particle size increased. The effect of surfactant concentration (sodium lauryl sulfate, SLS) on the encapsulated particle size was investigated using four different SLS concentrations in the 11% PVC system. The results showed that as the SLS concentration increased the particle size decreased, as expected. Also it was found that the minimum surfactant concentration that gives stable encapsulated TiO₂ particles is above 10 mM SLS. The role of HD in the recipe was studied for an artificial latex containing no TiO₂ and one prepared at 11% PVC, in terms of particle size before and after solvent stripping, and its effect on the T_g. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4504–4516, 2006     

三价铬电镀用氧化物涂层钛电极的电化学行为

采用极化曲线、循环伏安曲线及钝化曲线研究了三价铬电镀用含IrO2涂层钛电极的电化学行为.电极表面的扫描电镜照片表明,部分IrO2分散在针状结晶中,其余则分散在非晶相中.分析了三价铬镀铬过程中产生六价铬的原因.所研制的I型氧化物涂层钛电极具有高的析氧活性,其电催化活性与国外某公司的钛电极相当.在三价铬镀铬过程中,采用该电极连续电解120 A·h后,镀液中无Cr(Ⅵ)产生.     

水热法制备氧化锆微粉的进展

二氧化锆纳米粉是制造高科技陶瓷的重要原料，水热法是目前生产纳米粉体最具发展潜力的工艺方法之一。综述了水热法（包括水热沉淀、水热氧化、水热电埋弧、微波水热等）在生产纳米二氧化锆系粉体中的应用，以及水热法的发展情况。     

ClO2的制备方法及其储存条件的研究

本文采用了以还原性有机酸—草酸代替无机酸和无机还原剂还原氯酸钠制备二氧化氯的工艺,来研究生产二氧化氯的最佳方法以及二氧化氯溶液的储存条件。结果表明,该法工艺简单,成本低,无设备腐蚀,而且产品纯度高,产率可达90%以上。生产出的二氧化氯采用低温(1℃～2℃)蒸馏水吸收,效果较好,其溶液在密闭、低温、暗处等条件下,保存较好。     

Ring hydrogenation of naphthalene and 1-naphthol over supported metal catalysts in supercritical carbon dioxide solvent

Catalytic ring hydrogenations of naphthalene and 1-naphthol were studied over several supported metal catalysts in supercritical carbon dioxide solvent at low temperature. Higher concentration of hydrogen in supercritical carbon dioxide and lower reaction temperature were responsible for higher catalyst activity and selectivities to the desired partial ring hydrogenated products as compared with those observed in organic solvent for the same catalyst.     

PHOTOCATALYTIC OXIDATION OF ALDEHYDES/PCE USING POROUS ANATASE TITANIA AND VISIBLE-LIGHT-RESPONSIVE BROOKITE TITANIA

We have synthesized an annealed porous aerogel titania (LUAG2), which demonstrates a very high photocatalytic activity for aldehydes and perchloroethylene (PCE) photocatalytic oxidation (PCO) in gas phase under blacklight and fluorescent light irradiation. LUAG2 has a BET surface area of 237 m²/g and a porosity of 0.31 (volume fraction). X-ray diffraction (XRD) analysis shows LUAG2 is nearly pure anatase. It has improved the destruction of PCE and aldehydes as a group by 10-34% with black light compared to Degussa P-25. The optimum water vapor to butyraldehyde molar ratio is around 1/3. LUAG2 also shows better mineralization to CO₂ than Degussa P-25 TiO₂ does. Under irradiation of a 4 W fluorescent lamp LUAG2 gives a consistently higher conversion than that of Degussa P-25. The highly active photocatalyst indicates potential applications in indoor and outdoor environmental pollution control. A visible-light-responsive TiO₂, NTB 200, is also investigated for comparison purposes.     

新型光化学反应器及二氧化碳光解反应研究

研究设计了可产生波长小于200 nm真空紫外光的光化学反应器,首次利用该波段的光在该反应器中进行了CO2光解反应的研究。用氮气为发光介质对其进行光强标定,实验表明主要产生120、149、174 nm波长的光(N原子谱线);实验条件下CO2光解后生成产物CO,结果表明光源电流一定时产生CO的量与光源工作气体的压力有关,在CO2和N2反应物系中,光源内发光介质N2的压力在2 500 Pa左右时CO的产率最大,而在该反应物系中加入甲烷后,CO的产率明显增大。     

On the oxidative coupling of methane with carbon dioxide over CeO2/ZnO nanocatalysts

The nano-CeO₂/ZnO catalysts were prepared using a novel combination of homogeneous precipitation with micro-emulsion for oxidative coupling of methane with CO₂ as an oxidant. The prepared catalysts were compared with those prepared using the conventional impregnation. The catalysts prepared in two ways were characterized with FTIR, TEM, XRD and CO₂-TPD. The effects of the reaction temperature, the amount of ZnO doped in the catalysts and the average size were investigated. The experimental investigation demonstrated that methane conversion over the nano-CeO₂/ZnO catalysts prepared by the combined technique was higher than that obtained over catalysts prepared by the conventional impregnation. A better low-temperature activity has also been achieved over the nanocatalysts. There was no clear trend between the average size of nano-CeO₂/ZnO catalysts and their catalytic performance but methane conversion increased with increasing fractal dimension of nanocatalysts.     

二氧化氯消毒剂发生器的研制

对二氧化氯消毒剂的优点进行了阐述，介绍了化学法二氧化氯消毒剂发生器的工作原理、研制过程及推广使用价值。