Guoxing Lin

Active-oxygen species on non-reducible rare-earth-oxide-based catalysts in oxidative coupling of methane

From supplementary in situ Raman spectroscopic studies of active-oxygen species on non-reducible rare-earth-oxide-based catalysts in the oxidative coupling of methane (OCM) and structural adaptability considerations, further support has been obtained for our proposal that there may be an active and elusive precursor (of Ou20092− and Ou200922− adspecies), most probably Ou200932− formed from reversible redox coupling of an O2 adspecies at an anionic vacancy with a neighboring O2− in the surface lattice. This active precursor may initiate H abstraction from CH4 and be itself converted to OH−+Ou20092−, or it may abstract an electron from the oxide lattice and be converted to Ou200922−+O−. The prospect of developing this type of OCM catalysts is discussed.

Ag/La0.6Sr0.4MnO3/γ-Al2O3 catalysts for complete oxidation of methanol at low concentration

Ag-modified La 0.6 Sr 0.4 MnO 3 -based catalysts with the perovskite structure were prepared, and their activity for methanol complete oxidation was evaluated. The results showed that over a 6%Ag-modified 20% La 0.6 Sr 0.4 MnO 3 /γ-Al 2 o 3 catalyst, the T 50 and T 95 were as low as 395 and 413 K, respectively, and even at so low reaction temperature, the contents of the reaction intermediates HCHO and CO in the exit-gas were both under the detection limits. The origin of promoter action by Ag was discussed together with the results of spectroscopic characterization of the catalysts.

Dehydro-aromatization of CH4 over W-Mn(or Zn, Ga, Mo, Co)/HZSM-5(or MCM-22) catalysts*

Several promoted W/HZSM-5(or MCM-22)-based catalysts for DHAM reaction were developed.Over the W-Zn-Ga(or Mo-Co)/MCM-22 catalyst,70% selectivity of benzene (SBen) at 14∼17% conversion of methane (XCH4) could be achieved at 1073 K. XPS and NH3-TPD measurements demonstrated that heavy deposition of carbon was the main reason leading to deactivation of the catalyst. Reoxidation by air can regenerate the deactivated W-based catalyst effectively.

Carbon nanotubes-supported Rh-phosphine complex catalysts for propene hydroformylation

Two kinds of carbon nanotubes were synthesized from catalytic composition of CH 4 and CO, and employed as a novel carrier for the supported Rh-phosphine complex catalyst. The prepared catalyst displayed excellent performance for propene hydroformylation. The present work also provides an example for the application of the carbon nanotubes as an alternative to middle/arge-pore molecular sieves under certain circumstances.