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141.
142.
Mikhail Yu. Sinev Yurii P. Tulenin Olga V. Kalashnikova Viktor Yu. Bychkov Vladimir N. Korchak 《Catalysis Today》1996,32(1-4):157-162
The analysis of methane oxidation in a wide range of pressures (0.05–10 atm) demonstrates that the efficiency of CH3 radicals recombination is of great importance for high selectivity of C2 hydrocarbons formation. The relative efficiency of different “colliders” assisting the stabilization of exited C2H*6 molecules increases in the series: solid surface> Ar> He. The increase of the overall reaction rate upon increasing pressure of the inert gases in the case of catalysts having a higher surface area and more developed pore structure is likely due to the contribution of the surface-induced chain reaction in the volume of pores. 相似文献
143.
研究了Al2O3-TiB2陶瓷刀具材料在1000℃下的氧化行为,用XRD、SEM分析了氧化后的相组成及显微结构。结果表明:Al2O3-TiB2陶瓷材料在1000℃空气中氧化增重符合抛物线规律;随TiB2含量的增加,该材料的抗氧化能力下降。 相似文献
144.
Tetsuhiko Kobayashi Nolven Guilhaume Jun Miki Naoyuki Kitamura Masatake Haruta 《Catalysis Today》1996,32(1-4):171-175
In an attempt to develop new catalysts for the formation of formaldehyde from methane, the promotion effect of Fe on SiO2 and that of Sn on WO3 have been studied. The formation of formaldehyde on silica can be appreciably enhanced by the impregnation of Fe, as far as iron loadings are kept below 0.1 atom.% (Fe/Si × 100). In the case of Sn---W---Ox catalysts, both the addition of Sn to WO3, and that of W on SnO2 were effective to the selective formaldehyde formation. Absorption spectra (UV-Vis) and ESR measurements revealed that tetrahedrally coordinated Fe3+ in the silica network plays an important role in the formation of formaldehyde. A thin surface layer consisting of W and Sn oxides can account for the selective formaldehyde formation on the Sn---W---Ox catalysts. 相似文献
145.
146.
The same effect of temperature on the production of CO, CO2 and H2O was found during oxidative treatment of HY zeolites either impregnated with pyrene or coked. Therefore, pyrene oxidation can be used to specify the mechanism of coke oxidation. Three types of reactions can be distinguished: (a) condensation of polyaromatic molecules, (b) oxidation of polyaromatics into aldehydes, ketones, acids and anhydrides and (c) decarbonylation or decarboxylation of oxygenated compounds, all these reactions involving protonic sites. 相似文献
147.
Studies of the complete oxidation of methane on a Pt electrode-catalyst in the cell with a solid proton-conducting electrolyte (CH4 + O2, Pt ¦ SrCe0.92Dy0.08O3 ¦ Pt, H2O + N2) were carried out. The non-Faradaic effect of electrochemical hydrogen pumping on the rate of methane oxidation has been demonstrated. The induced change in the reaction rate at anodic polarization of a Pt electrode-catalyst was over two orders of magnitude higher than the rate of hydrogen pumping from the reaction zone through the electrolyte. 相似文献
148.
碳钢与不锈钢表面高浓度渗铬法 总被引:3,自引:1,他引:2
在氩气气氛下,应用固体渗铬填料法对碳钢、不锈钢作了表面高铬浓度的渗铬处理,探讨了渗铬温度、时间和渗铬组分对渗层表面铬含量、厚度,试样增重和物相组分影响,碳钢、不锈钢的表面渗铬浓度分别达80-94wt%和70-82wt%。 相似文献
149.
A novel and efficient way of producing of aldonic acids is reported. The selective catalytic oxidation of monosaccharides (arabinose, ribose, xylose, lyxose, mannose, rhamnose, glucose, galactose, N-acetyl-glucosamine) and disaccharides (lactose, maltose, cellobiose, melibiose) on Au, Pd and Pt catalysts was investigated. By using the gold catalyst, a total selectivity with respect to aldonic acids and a high catalytic activity for all investigated sugars was found. The reaction conditions for the production of maltobionic and lactobionic acids via oxidation on gold catalysts were optimised. A high long-term stability of two different gold catalysts for the oxidation of maltose and lactose, respectively, was found. 相似文献
150.
The partial oxidation of methane over the supported Rh (0.8 wt.%) catalysts was investigated. Two kinds of supports were used, MgO and Ti-modified MgO (prepared by grafting technique). Among the Ti-modified MgO supports, two different compounds were used as source of Ti: inorganic (chloride) and organic (alkoxide). The catalytic performance of Rh-supported catalysts depends on the support and varies in the sequence: Ti-MgO/I > Ti-MgO/O > MgO. Ti-containing catalysts exhibited higher activity and selectivity compared to MgO, which is especially noticeable at low temperature. Possible explanations for the phenomena observed were proposed on the basis of characterization results. 相似文献