990 resultados para Cu-ZnO-ZrO2 : HZSM-5


Relevância:

100.00% 100.00%

Publicador:

Resumo:

中国科学院山西煤炭化学研究所

Relevância:

100.00% 100.00%

Publicador:

Resumo:

中国科学院山西煤炭化学研究所

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Microwave effects have been shown to promote the activation of NOx molecules in the process of selective reduction of NO by CH4 over an In-Fe2O3/HZSM-5 catalyst and to enhance the water tolerance of this catalyst for NO reduction.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The formation of surface alkoxy species on nanosized HZSM-5 and microsized HZSM-5, after exposure to methanol and subsequent conversion to olefins, has been investigated by in situ solid state NMR. Compared to microsized HZSM-5 zeolite, the nanosized HZSM-5 zeolite was found to exhibit a higher affinity for trapping methanol species. Activation of the adsorbed methanol species resulted in the formation of various surface alkoxy species with different rigid characters, including the carboxylate-like surface species, as evidenced by deconvolution of the related spectra. The present results support the existence of the so-called carbon-pool in the conversion of methanol, which serves as the reaction precursor not only for the coupling of the species to form olefins, but also for uncontrolled polymerization to give coke on the surface. The nanosized HZSM-5 shows a distinct resistance to the formation of carbonaceous deposits on the surface.