%0 Journal Article
%T CO Hydrogenation over Transition Metals (Fe, Co, or Ni) Modified K/Mo2C Catalysts
%A Minglin Xiang
%A Juan Zou
%J Journal of Catalysts
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/195920
%X Transition metals (Fe, Co, or Ni) modified K/Mo2C catalysts were prepared and investigated as catalysts for CO hydrogenation. The addition of Fe, Co, or Ni to K/Mo2C catalyst led to a sharp increase in both the activity and selectivity of , but the promotion effects were quite different and followed the sequence: Ni > Co > Fe for the activity and Fe > Co > Ni for the alcohol selectivity. For the products distributions, it also displayed some differences; Co promoter showed much higher hydrocarbon selectivity than Fe or Ni promoter, but Fe or Co promoter gave lower methane selectivity than Ni promoter, and Fe promoter showed the highest selectivity. 1. Introduction The production of fuels from coal via syngas is one of the most industrial challenges for near future. As for Fischer-Tropsch reaction, reaction proceeds on transition metal supported catalysts, the catalysts currently investigated being Co, Fe, or Ru supported on oxides, such as Al2O3, SiO2, TiO2, and ZrO2 [1¨C3]. However, the application of such an attractive synthesis still suffers from the lack of high performance catalysts. Thus, great efforts are still being made to improve both activity and selectivity of catalysts. Since 1973, when Levy and Boudart [4] reported that WC displayed reactivity similar to Pt for hydrogenation reactions, there has been considerable interest in the catalytic properties of metal carbides, particularly of the group VI transition metals. Synthesis of hydrocarbons from CO hydrogenation over Co or Ru promoted molybdenum carbides has been evidenced by Griboval-Constant et al. [5], and the results reveal that molybdenum carbide gives light hydrocarbons and alcohols; the addition of Ru decreases the alcohol production yet Co increases formation of heavy hydrocarbons. As reported elsewhere [6], promotion of molybdenum carbide by potassium has been found to greatly enhance the selectivity to alcohols. For MoS2-based catalysts, the addition of transition metals, such as Co, Ni, Rh, and Pd, is found to be able to improve the catalytic activity and selectivity of alcohols [7¨C9]. In this regard, it also can be speculated that the transition metals may have positive effect on both alcohols and heavy hydrocarbons formation from CO hydrogenation over Mo2C-based catalysts, and still much less information is available. Thus, the aim of this work is to study the influence of addition of transition metals, such as Fe, Co, or Ni, on K/Mo2C catalyst in terms of catalytic activity and selectivity in CO hydrogenation reaction. 2. Experimental 2.1. Sample Preparation The molybdenum
%U http://www.hindawi.com/journals/jcat/2013/195920/