摘要
建立了一整套Ｒｈ簇高分散催化剂的制备技术和方法，制备出了分散的Ｒｈ＿２／Ａｌ＿２Ｏ＿３和Ｒｈ＿４／Ａｌ＿２Ｏ＿３簇催化剂。Ｈ＿２化学吸附表明这些样品具有很高的金属分散度，且分散度随Ｒｈ簇担载量的增加而降低。ＣＯ吸附态测定表明，当簇合物的Ｒｈ担载量（ｗ％Ｒｈ）为０．７％时分散度最高。ＣＯ分子在催化剂上只有一种吸附方式─—孪生吸附，实现了ＣＯ吸附态的“分离”，即催化剂上只存在一种吸附中心。表明催化剂的金属粒度已达到均一。这一结果还表明可通过原子簇衍生催化剂的方法来控制ＣＯ分子在Ｒｈ催化剂上的吸附方式。催化剂制备过程的原位红外光谱测试结果表明：Ｒｈ簇与γ－Ａｌ＿２Ｏ＿３作用形成高分散是一个很快的过程。
A set of preparation techniques and methods for highly dispersed Rh clustercatalysts was established and used to obtain highly dispersed Rh_2/Al_2O_3 and Rh_4/Al_2O_3 cata-lysts.Hydrogen chemisorption showed that Rh was highly dispersed on these samples andthe dispersion degree decreased with increasing Rh loading, Carbon monoxide adsorptionstate study showed a maximum degree of Rh dispersion at a Rh loading of 0.7%, and on thisparticular catalyst only one CO adsorption state-twin chemisorbed CO was observed. Thus,the separation of CO chemisorption states was realized. The particle size of the disparsedmetal was extremely uniform. The adsorption state of CO on Rh- based catalyst could becontrolled by using Rh cluster in preparation. In situ IR absorption measurement deeringpreparation showed that the formation of highly dispersed Rh on γ-Al_2O_3 is a fast step.
出处
《燃料化学学报》
EI
CAS
CSCD
北大核心
1994年第4期362-368,共7页
Journal of Fuel Chemistry and Technology
基金
国家自然科学基金
关键词
铑原子簇催化剂
分散度
吸附态
催化剂
一氧化碳
cluster catalyst, highly dispersed catalyst, adsorption state, in situ IR
