Characteristics of zeolite-supported iron catalysts prepared from iron cyanide complexes

Abstract

This chapter discusses the catalytic properties of metal clusters in zeolites. Zeolites and molecular sieves offer a particularly intriguing option for providing channels and cage structures, in which small clusters might be formed and stabilized. The unusual properties of small particles might then be exploited, and the zeolitic structure may itself be utilized to fine-tune the catalytic properties. Several characterization techniques have been used in the examination of clusters in zeolites. The most widely used and/or useful appear to be extended X-ray absorption fine structure (EXAFS), the radial electron distribution (RED) method using X-ray scattering data (XRD), magnetic methods, electron microscopy, electron spin resonance (ESR), nuclear magnetic resonance (NMR) of adsorbed xenon, Mössbauer spectroscopy, X-ray photoelectron spectroscopy (XPS), chemisorption, including the use of temperature-programmed reduction (TPR), temperature-programmed oxidation (TPO) and related methods and infrared (IR) spectroscopy. The chapter reveals that n-Butane conversion has been used as a test reaction for determining the catalytic properties of metal particles in zeolites and the parameters influencing these properties. Platinum has received the most attention and in these studies parameters such as particle size, support acidity, addition of other, metals, and sulphur poisoning are examined.