摘要
采用共沉淀法制备了Au/Fe2 O3 催化剂 ,并系统地考察了制备参数对其催化WGS性能的影响 .通过BET ,XRD ,XRF ,H2 TPR和HRTEM等表征手段 ,初步考察了Au/Fe2 O3 催化剂具有高催化活性的原因 .结果表明 ,金负载量、沉淀剂种类、沉淀方式、沉淀 pH值、焙烧气氛和焙烧温度对Au/Fe2 O3 催化剂的催化性能均具有较大的影响 .Au/Fe2 O3 催化剂的低温高活性是纳米Au与Fe3 O4协同作用的结果 ;Au/Fe2 O3 催化剂的高温活性是由于活性相Fe3 O4起主要作用的结果 .
The Au/Fe 2O 3 catalyst for water gas shift reaction was prepared by coprecipitation method. Under vigorous stirring, the aqueous solution of HAuCl 4·4H 2O and Fe(NO 3) 3·9H 2O was firstly mixed, then the aqueous mixture and the aqueous solution of Na 2CO 3·10H 2O were simultaneously added dropwise to deionized water at 60 ℃ kept through flowing water and at a constant pH value adjusted by diluted Na 2CO 3. The brown suspension was kept under stirring for desired time. After cooling to room temperature, the resulting precipitate was alternatively centrifuged and washed until no AgCl precipitate was noted on dropping AgNO 3 solution into the filtrate. Further, the paste was dried at 120 ℃, then heated to desired temperature at a heating rate of 5 ℃/min and calcined at the corresponding temperature for desired time. The effect of the preparation parameters was systematcally explored on the WGS reactivity. The results showed that, some preparation parameters, such as gold loading, precipitant, precipitation manner, pH value during precipitation, calcination atmosphere, temperature, etc, can exert much influence on the catalyst activity. The gold introduced by coprecipitation can highly disperse on the surface of Fe 2O 3 support. Moreover, the nanometer gold particles can depress the crystallization of the support and significantly reduce the reduction temperature of the support toward Fe 3O 4. The high catalytic activity of Au/Fe 2O 3 catalyst under low temperature can be attributed to the synergism between nano scale gold particle and Fe 3O 4 phase, while the latter still works at high reaction temperature. If the aggregation of the nano scale gold particles occurs, the catalytic activity decreases.
出处
《催化学报》
SCIE
EI
CAS
CSCD
北大核心
2003年第12期957-963,共7页
基金
国家自然科学基金资助项目 ( 2 0 2 710 12 )
福建省科技计划项目 ( 2 0 0 2H0 2 6)
关键词
金
氧化铁
负载型催化剂
水煤气变换反应
制备参数
gold, iron oxide, supported catalyst, water gas shift reaction, preparation parameter
