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Abstract: Oxidative steam reforming of ethanol over an Ir/CeO2 catalyst was investigated. Ethanol dehydrogenation to acetaldehyde and decomposition to methane and carbon monoxide were the primary reactions at low temperatures, and complete reforming of ethanol was achieved at 773K with hydrogen, carbon oxides and methane as the only products in the outlet stream. More importantly, stability test revealed that the Ir/CeO2 catalyst could show rather stable catalytic performance for 60h time-on-stream without deactivation. The improvement was attributed to the effective prevention of the sintering of the highly dispersed Ir particles through the strong interaction between Ir and CeO2 and to the significant resistance to coke deposition due to the higher oxygen storage-release capacity of ceria. [Copyright &y& Elsevier]

Abstract: Enhanced performance of methane dehydro-aromatization reaction (MDA) were achieved on a Mo-based HZSM-5 zeolite catalyst in which HZSM-5 were pretreated by a proper amount of NH4F (Mo/HZ(F)). The results of NH3-TPD and 27Al MAS NMR demonstrated that the number of Brönsted acid sites decreased on the HZSM-5 zeolite and Mo/HZSM-5 catalyst after NH4F treatment. TGA and TPO measurements showed that the Mo/HZ(F) catalysts were highly resistant to coke deposition, which resulted mainly from the elimination of the Brönsted acid sites after the pretreatment of the HZSM-5 zeolite with NH4F. [Copyright &y& Elsevier]

Abstract: The catalytic behavior of Ni/CeO2 catalysts was investigated for methane decomposition at 773K. Ni/CeO2 catalysts prepared by impregnation and deposition–precipitation methods showed much higher hydrogen formation rates than that of Ni/CeO2 catalyst prepared by coprecipitation method, which exhibited relatively higher CO formation rate. CH4-TPSR measurements confirmed that CO formation is inevitable during methane decomposition, since the lattice oxygen of ceria could react with the deposited carbons. TEM observations further indicated that the morphologies as well as the reactivities of the deposited carbons are strongly dependent on the interaction degrees between Ni and ceria, which in turn explains the differences in the catalytic activity of the Ni/CeO2 catalysts for methane decomposition. The Ni/CeO2 catalyst prepared by coprecipitation method exhibited rather strong metal–support interaction probably through the formation of Ni–O–Ce solid solution, resulting in much lower hydrogen formation rate and relatively higher CO production. [Copyright &y& Elsevier]

The effect of steam on the acid strength of H3PW12O40 (HPW)/SiO2 · nH2O was determined by the Hammett indicators. When the steam content in N2 was 1.6%, the acidity (H0 > −13.7) of HPW/SiO2 · nH2O could be kept for over 10 h at 300 °C, but for only 2 h when steam was lacking. When it was used as a catalyst for skeletal isomerization of n-butane to isobutane at 300 °C, the HPW/SiO2 · nH2O showed stability in the presence of steam (1.6% in feed) better than that without steam, due to a suppression of the loss of crystalline water. [Copyright &y& Elsevier]