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	NOx催化的甲烷气相氧化反应; Gas-Phase Oxidation of Methane Catalyzed by NOx
	阎震 ; 寇元 ; 肖超贤
	2003
关键词	甲烷 氧化 氮氧化物 均相催化 催化燃烧 methane oxidation nitrogen oxide homogeneous catalysis catalytic combustion
英文摘要	考察了没有固体催化剂时NOx对甲烷气相氧化的催化作用,并用原位红外光谱研究了CH4-O2-NOx体系随温度的变化. 实验结果表明,NOx对甲烷气相氧化有很高的催化活性. 在20%CH4-10%O2体系中加入0.05%～0.2%的NO后,反应温度可降低200～300 ℃,在650～700 ℃下反应时,CH4转化率和CO选择性可分别达到38%和90%,产物中的n(H2)/n(CO)比为0.4～0.7. 反应产物中可观察到有甲醛、甲醇和乙烯等,通过改变反应条件可以控制各组分的相对浓度.; Catalytic conversion and catalytic combustion of CH4 have received extensive attention because of their potential to synthesize useful chemicals and to reduce pollutant emissions. Both the processes require activation of CH4, which has been mostly achieved over solid catalysts to date. In the catalytic conversion of CH4, the promotional effects of NOx on CH4 oxidation were reported by some researchers, but the role that NOx may play in CH4 activation and the importance of this gas-phase reaction have not received more attention. This work investigated the catalytic effect of NOx on partial oxidation of CH4 in the absence of solid catalyst. The product distribution was studied by in-situ FT-IR under different reaction conditions. The results showed that the addition of a small amount of NO into 20% CH4-10 % O-2 system decreased the reaction temperature by 200 similar to 300 degreesC. At 650 similar to 700 degreesC, the CH4 conversion and CO selectivity were 38 % and 90 %, respectively, and n (H-2) /n(CO) = 0.4 similar to 0.7. The optimum conditions for CO formation were n (CH4) /n (O-2) = 2 and low flow rate. Some reducible substances, such as HCHO, CH3OH and C2H4, were also observed in the products. The HCHO was formed at 460 degreesC, then CO (480 degreesC), CH3OH (500 degreesC), and C2H4(540 degreesC) were formed. Low temperature favours the formation of HCHO and CH3OH, while high temperature favours C2H4. Under strong oxidizing conditions (n (O-2) /n (CH4) = 5), NOx also exhibits considerable catalytic activity and selectivity for CH4 conversion to CO. For 0.4 % CH4-2 % O-2 System, the temperature for CH4 activation is higher than 800 degreesC in the absence of NOx. In the presence of NOx, however, the activation temperature is reduced to below 570 degreesC. The addition of 0.06 % NO results in the increase of CO yield from 25 % to 68 %. It was shown that no reaction was observed for CH4-NOx system (without O-2) under the reaction conditions, indicating that the NO2 formation is a prerequisite for CH4 activation. Also, no decrease of NO/NO2 concentration was observed Lip to 950 degreesC, indicating that NOx cannot be reduced by CH4 in the absence of solid catalyst. Both CH4 conversion and CO yield reached a maximum when phi (NO) = 0.04 % similar to 0.06 %, while the highest TOF (turnover frequency) of 40 s(-1) was obtained when phi (NO) = 0.01 %; http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000180791900010&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701 ; SCI(E); 中文核心期刊要目总览(PKU); 中国科技核心期刊(ISTIC); 中国科学引文数据库(CSCD); 1; 1; 37-41; 24
语种	中文
出处	万方 ; SCI ; http://d.g.wanfangdata.com.cn/Periodical_cuihuaxb200301010.aspx
出版者	催化学报
内容类型	其他
源URL	[http://hdl.handle.net/20.500.11897/80718]
专题	化学与分子工程学院
推荐引用方式 GB/T 7714	阎震,寇元,肖超贤. NOx催化的甲烷气相氧化反应, Gas-Phase Oxidation of Methane Catalyzed by NOx. 2003-01-01.

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