Metal-containing zeolites, various preparations

Various both heterogeneous and homogeneous catalytic systems have been developed for methane oxidation to methanol in gas or liquid phases. Achievements in this field before 2008 are discussed in several previous reviews [10,34,60]. Inspired by the high performance of MMO, Fe- and Cu-containing zeolites were prepared to mimic catalytically active metal-oxide sites and applied for gas-phase oxidation of methane to methanol using N2O [61,62] or O2 [63,64] as oxidizing agents. However, the achieved methanol yields are rather low. 

A novel method for the preparation of metal containing small pore zeolites is described. The metal is introduced at elevated temperatures by solid state ion exchange. The zeolites obtained by the new method are highly shape selective. As an example, the competitive hydrogenation of an equimolar mixture of hexene-(l) and 2,4,4-trimethylpentene-(l) over various platinum, palladium and rhodium containing 8-membered ring zeolites was studied. 

Tn the course of experimentation with formulations of silica, alumina, and A various alkali metal oxides in attempts to prepare new synthetic zeolites, a formulation containing cesium replacing some of the sodium in a typical faujasite preparation yielded a new crystalline zeolitic product which showed a typically cubic powder diagram having a body-centered pattern of... 

Composites containing different types of guests (metal or alloy particles, oxides, sulfides, complexes, polymers) in the cavities of zeolite hosts are prepared for various appHcations in materials research and catalysis. Except for quality assessment by detection of extra-zeolite material after synthesis or thermal treatments, photoemission plays a largely auxiliary role in this area, cooperating with bulk techniques such as X-ray absorption, UV-Vis, IR of probe molecules, and temperature-programmed reduction. The attention drawn to the significance of intra-zeolite potentials by XPS studies [12] has, however, contributed to the elaboration of a new theory of metal-support interactions [18,19]. 

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