摘要
考察了NO在硫化NiW/Al2O3催化剂上分解和还原的规律.结果表明,在350℃以上,NO完全分解,但同时催化剂的晶格硫因氧化而以SO2的形式大量流失,最终导致催化剂完全失活.在NO分解反应体系中,按化学计量比引入的H2与晶格硫竞争消耗NO分解所生成的Oad,使晶格硫的氧化在一定程度上得到抑制;氧化的部分晶格硫能通过一系列氧化还原过程重新进入催化剂晶格,导致晶格硫的流失速度和程度得到缓和,催化剂可在较长的时间内保持较高的NO转化活性.但是,催化剂的活性最终仍会因为大部分晶格硫逐渐流失而大幅度下降.
To investigate the possibility of simultaneous catalytic elimination of sulfur dioxide and nitric oxide by hydrogen, the reactions of NO decomposition and reduction by H2 were performed over sulfided NiW/Al2O3 catalyst, which was prepared by impregnation method and then presulfided with a gas mixture of 0.5%SO2- 2.7 % H2-Ar balance. The results showed that NO was decomposed completely over the sulfided catalyst accompanied with the formation of SO2, which resulted from the oxidation of the catalyst lattice sulfur. This oxidation led to complete loss of lattice sulfur and deactivation of the catalyst. After addition of equivalent H2 to NO stream, Oad produced by NO decomposition was consumed by H2 and lattice sulfur competitively, which suppressed the oxidation of lattice sulfur to a certain extent. Furthermore, part of the oxidized lattice sulfur could return to lattice sulfur to decrease its loss after a series redox reactions. The catalyst could maintain high activity for the reduction of NO by H2 for a long time compared with the NO decomposition.
出处
《催化学报》
SCIE
EI
CAS
CSCD
北大核心
2005年第8期724-728,共5页
基金
国家自然科学基金资助项目(20076017
20476032)
广东省自然科学基金资助项目(030951)
广东省科技攻关资助项目(2KB06601S).
关键词
一氧化氮
催化还原
镍
钨
氧化铝
负载型催化剂
nitric oxide, catalytic reduction, nickel, tungsten, alumina, supported catalyst
