Chinese Journal of Catalysis ›› 2018, Vol. 39 ›› Issue (1): 157-166.DOI: 10.1016/S1872-2067(17)62967-X

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Ru/FeOx catalyst performance design: Highly dispersed Ru species for selective carbon dioxide hydrogenation

Di Zhanga,b, Jingjie Luob, Jiajie Wanga, Xin Xiaoa, Yuefeng Liuc, Wei Qib, Dang Sheng Sub,c, Wei Chua   

  1. a Department of Chemical Engineering, & Institute of New Energy and Low Carbon Technology, Sichuan University, Chengdu 610065, Sichuang, China;
    b Shenyang National Laboratory for Materials Science(SYNL), Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, Liaoning, China;
    c Dalian National Laboratory for Clean Energy(DNL), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
  • Received:2017-09-20 Revised:2017-11-01 Online:2018-01-18 Published:2018-01-19
  • Contact: 10.1016/S1872-2067(17)62967-X
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (21476145, 91645117) and China Postdoctoral Science Foundation (2016M600221).

Abstract:

A series of Ru/FeOx catalysts were synthesized for the selective hydrogenation of CO2 to CO. Detailed characterizations of the catalysts through X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and temperature-programmed techniques were performed to directly monitor the surface chemical properties and the catalytic performance to elucidate the reaction mechanism. Highly dispersed Ru species were observed on the surface of FeOx regardless of the initial Ru loading. Varying the Ru loading resulted in changes to the Ru coverage over the FeOx surface, which had a significant impact on the interaction between Ru and adsorbed H, and concomitantly, the H2 activation capacity via the ability for H2 dissociation. FeOx having 0.01% of Ru loading exhibited 100% selectivity toward CO resulting from the very strong interaction between Ru and adsorbed H, which limits the desorption of the activated H species and hinders over-reduction of CO to CH4. Further increasing the Ru loading of the catalysts to above 0.01% resulted in the adsorbed H to be easily dissociated, as a result of a weaker interaction with Ru, which allowed excessive CO reduction to produce CH4. Understanding how to selectively design the catalyst by tuning the initial loading of the active phase has broader implications on the design of supported metal catalysts toward preparing liquid fuels from CO2.

Key words: Highly dispersed Ru/FeOx catalyst, Temperature-programmed surface reaction, CO2 selective hydrogenation, Product selectivity, Hydrogen adsorption