通过表面氧化还原反应制备的Rh-Ge/Al₂O₃催化剂上CO吸附的傅里叶变换红外光谱研究。

FTIR studies of CO adsorption on Rh-Ge/Al2O3 catalysts prepared by surface redox reactions.

作者信息

Lafaye Gwendoline, Mihut Corina, Especel Catherine, Marécot Patrice, Amiridis Michael D

机构信息

Laboratoire de Catalyse en Chimie Organique, UMR CNRS 6503 Université de Poitiers, 40 Avenue du Recteur Pineau, F-86022 Poitiers Cedex, France.

出版信息

Langmuir. 2004 Nov 23;20(24):10612-6. doi: 10.1021/la049692l.

DOI:10.1021/la049692l

PMID:15544392

Abstract

A series of bimetallic Al2O3-supported Rh-Ge catalysts was prepared by surface redox reactions under controlled hydrogen atmosphere. The surface properties of these catalysts were probed via in-situ FTIR spectroscopic studies of adsorbed CO and were compared to those of monometallic Rh catalysts that had undergone similar treatments. The results indicate that Ge addition results in the formation and stabilization of smaller rhodium ensembles at the expense of larger Rh0 surfaces. A charge-transfer mechanism from Ge to Rh is also inferred by the IR results for the high Ge loading samples. Air exposure of the catalysts leads to an irreversible segregation of the two metals and formation of large Rh crystallites.

摘要

通过在可控氢气氛下的表面氧化还原反应制备了一系列双金属Al2O3负载的Rh-Ge催化剂。通过对吸附的CO进行原位傅里叶变换红外光谱研究来探测这些催化剂的表面性质，并将其与经过类似处理的单金属Rh催化剂的表面性质进行比较。结果表明，添加Ge会导致形成并稳定较小的铑团簇，同时较大的Rh0表面减少。对于高Ge负载量的样品，红外结果还推断出从Ge到Rh的电荷转移机制。催化剂暴露在空气中会导致两种金属不可逆地分离并形成大的Rh微晶。