y*********n
发帖数: 40 | 1 【 以下文字转载自 ChemEng 讨论区 】
发信人: yijijuechen (yijijuechen), 信区: ChemEng
标 题: 请教催化大牛一个简单问题
发信站: BBS 未名空间站 (Wed Jun 10 11:23:10 2009, 美东)
小弟现在开始做用水和CO2重整甲烷的实验，我看到很多文献报道用BaO去修饰载体，以
提高活性和防止碳沉积，我不太明白，难道BaO不和水和CO2反应吗？催化剂应该失活才
对，谢谢大牛指点 | f*****t
发帖数: 122 | 2 BaO is not the active component, it is the promoter. There must be other
transition metals as the main active components for your catalysts.
Basically, alkaline metals, such as K, Ba etc., are used to adjust the
electronic properties of the active metals by their interaction with the
main components, thus affecting the catalytic performance .
You are asking if BaO reacts with CO2 to form BaCO3, if I understand
correctly. Well, that might happen. The point is the nature of the active
components. | y*********n
发帖数: 40 | 3 谢谢你的详细回答，
非常有可能，BaO可能已经进入到其他氧化物的晶格，比如说Ni/CeO2-BaO,这个体系已
经生成BaCeO3,但是BaCeO3在水和二氧化碳中非常不稳定，最终催化剂还是变成CeO2和
BaCO3,这能否说明其实起到作用的很有可能是碱性的元素，它处于什么化合物当中，不
重要
比如说Ni/CeO2-BaCeO3 的催化活性可能相似，
谢谢
support
does
So
【在 f*****t 的大作中提到】
: BaO is not the active component, it is the promoter. There must be other
: transition metals as the main active components for your catalysts.
: Basically, alkaline metals, such as K, Ba etc., are used to adjust the
: electronic properties of the active metals by their interaction with the
: main components, thus affecting the catalytic performance .
: You are asking if BaO reacts with CO2 to form BaCO3, if I understand
: correctly. Well, that might happen. The point is the nature of the active
: components.
| f*****t
发帖数: 122 | 4 In addition to your thinking of the interaction between the support and
promoters, here are my two cents: (1) people usually focus more on the
interaction between the active Ni and Ba promoter, possibly some crystalline
phase such as Ni-Ox-Ba, (2) the charge transfer between the ceria and the
active sites. You are interested in the substitution of Ce by Ba in the
support, note that Ce is 4+ and Ba is 2+. |
|
