The catalytic activity of DRM reaction over 1M-1Co-1Ce/AC-N (M = Ca and Mg) catalysts was investigated at 800 °C and under atmospheric pressure. By promoting N-doped activated carbon supported Co-Ce catalysts with alkaline-earth metals to obtain catalysts with better catalytic performance is the main purpose of study. The catalysts were prepared by wet-impregnation method and the influence of impregnation sequence on catalytic performance was also studied. The characterization was conducted using TPR, TPD , XPS, TEM and Raman. The catalyst 1Ca-1Co-1Ce/AC-N promoted with Ca and prepared by co-impregnation exhibited higher catalytic activity than unmodified. This was mainly due to the stronger interaction between metal and support as well as better active metals dispersion. The 1Ca-1Co-1Ce/AC-N catalysts also displayed excellent stability and XPS results indicated that higher Ce 3+ /Ce 4+ and O β /(O α +O β ) ratios were observed on this catalyst. However, the catalyst 1Co-1Ce/1Ca/AC-N prepared with sequential impregnation exhibited poor stability. In addition, the TEM of the spent catalysts revealed that there were a large number of carbons were generated on active metal surface.
Hailin Xiao,Junliang Wu,Xueqing Wang,Jialing Wang,Shengpeng Mo,Mingli Fu,Limin Chen,Daiqi Ye
Deep catalytic oxidation of toluene in low concentrations by ozone on a supported Pt-Ce/BEA catalyst using a facile preparation method was investigated. The catalyst was prepared using a simple grinding and calcination process, and then characterized by inductively coupled plasma elemental analysis, X-ray diffraction, transmission electron microscopy, H 2 temperature programmed reduction, O 2 and toluene temperature programmed desorption, and ultraviolet Raman spectroscopy. The characterization results showed that Pt nanoparticles and CeO 2 intimately contacted on the surface of the catalyst, and a strong interaction occurred between them. The catalyst was employed for toluene oxidation with ozone because a strong interaction occurs between the Pt NPs and CeO 2 . We aimed to investigate the interaction between the Pt NPs and CeO 2 ; thus, we compared the three catalysts. Pt-Ce/BEA exhibited superior catalytic performance (>99% toluene conversion and >99% CO 2 selectivity at 90 °C) compared to Pt/BEA (85% toluene conversion and 63% CO 2 selectivity) and Ce/BEA (>99% toluene conversion and 59% CO 2 selectivity). The strong interaction between the Pt nanoparticles and CeO 2 increased the amount of oxygen vacancy and thus improved the ozone decomposition activity, which yielded more active oxygen species and contributed to the toluene oxidation.
Lei Chen,Zhichun Si,Xiaodong Wu,Duan Weng,Zhenwei Wu
A MnO x –NbO x –CeO 2 catalyst for low temperature selective catalytic reduction (SCR) of NO x with NH 3 was prepared by a sol–gel method, and characterized by NH 3 –NO/NO 2 SCR catalytic activity , NO/NH 3 oxidation activity, NO x /NH 3 TPD , XRD , BET, H 2 -TPR and in-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). The results indicate that the MnO x –NbO x –CeO 2 catalyst shows excellent low temperature NH 3 -SCR activity in the temperature range of 150–300°C. Water vapor inhibits the low temperature activity of the catalyst in standard SCR due to the inhibition of NO x adsorption. As the NO 2 content increases in the feed, water vapor does not affect the activity in NO 2 SCR. Meanwhile, water vapor significantly enhances the N 2 selectivity of the fresh and the aged catalysts due to its inhibition of the decomposition of NH 4 NO 3 into N 2 O.
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