In situ Ga K edge XANES study of the activation of Ga/ZSM-5 prepared by chemical vapor deposition of trimethylgallium

Abstract

The activation of a dimethylgallium/ZSM-5 precursor to well-defined reduced and oxidized species is studied by in situ Ga K edge XANES. The precursor is prepared by chemical implanting of trimethylgallium on acidic HZSM-5. Subsequent reduction leads to charge-compensating Ga + species. Direct oxidation of the trimethylgallium precursor leads to various forms of gallium oxide and regeneration of Brønsted acid protons. Oxidation of the reduced Ga + species yields predominantly to GaO + species. The GaO + species exhibit a much higher H 2 /D 2 exchange activity than reduced Ga + species.

Performances of Fe-[Al, B]MFI catalysts in benzene hydroxylation with N2O

“…Fe Kedge XANES results [43] showed a distinct difference in the characteristics of iron in Fe-silicalite (without aluminium) and FeZSM-5 (with aluminium), in agreement with UV-vis DR data (Fig. 2).…”

Fe, Co and Cu-incorporated TUD-1: Synthesis, characterization and catalytic performance in N2O decomposition and cyclohexane oxidation

“…In various studies on the so called ex-framework Fe-ZSM-5 [20] it was never excluded that these particles are of importance to the N 2 O decomposition catalysis. Also the presence of Al in these particles appeared likely, and this led indirectly to the proposal that Al in vicinity of Fe is beneficial for the catalysis [35]. Because of the different nature of the nano-particles in steamed ZSM-5 catalysts and TUD-1 catalysts, conclusions related to the former system cannot be made.…”

Stability and reactivity of active sites for direct benzene oxidation to phenol in Fe/ZSM-5: A comprehensive periodic DFT study

“…Another interesting application is in the field of hydrocarbon oxidation. The Fe/ZSM-5 catalyst can oxidize methane to methanol and benzene to phenol, but only the latter reaction can be carried out in a catalytic manner so far [11][12][13][14][15][16]. There are quite some data in support of isolated Fe 2+ ions as the active site for benzene oxidation, whereas dispersed oligonuclear and most likely binuclear Fe complexes form the active sites for catalytic N 2 O decomposition .…”