Morphology Effect of Ceria on the Ammonia Synthesis Activity of Ru/CeO2 Catalysts

  • Pengcheng Liu
  • Ruyue Niu
  • Wei Li
  • Shuang WangEmail author
  • Jinping LiEmail author


Three Ru/CeO2 catalysts with different morphologies of CeO2 (cube spheres, microspheres and nano rods) were used to evaluate the support-morphology-dependent ammonia synthesis activity. Catalytic experiments show that the Ru/CeO2–CS catalyst has higher catalytic activity (27,000 µmol g−1 h−1) than Ru/CeO2–MS (21,000 µmol g−1 h−1) and Ru/CeO2–NR (15,000 µmol g−1 h−1) under the reaction conditions of 450 °C, 3 MPa, H2/N2 = 3:1 (60 mL min−1). The transmission electron microscopy analysis showed that the dispersion of active metal Ru is affected by the morphology of CeO2. Brunauer–Emmett–Teller indicates that the 3–5 nm the pore size of CeO2 supports contributes to the active metal Ru enters the pores of the CeO2 support, which improves the dispersion of Ru and prevents the sintering and agglomeration of Ru in some extent. TPR studies shown that the reduction of ruthenium oxide is influenced by the morphology of CeO2. XPS and CO2-TPD demonstrated that the Ru/CeO2–CS catalyst exhibited higher surface oxygen vacancies, higher basic site density and lower Ru binding energy, indicating that Ru nanoparticles in Ru/CeO2–CS is more electron-rich and are more capable of back-donating electrons to adsorbed N2 and subsequently activate N2. Our results indicate that the morphology effect of the CeO2 supports on the Ru/CeO2 catalyst is related to the pore size distribution and the surface oxygen vacancies of the CeO2 supports, ratio of Run+, basic site density.

Graphical Abstract

The CeO2–CS (cube spheres) morphology facilitated the dispersion of the active metal Ru and the 3 nm the pore size of CeO2–CS contributed to the Ru enters the pores of the support. And the Ru/CeO2–CS catalyst exhibited higher surface oxygen vacancies and lower Ru binding energy, which enhanced the adsorption of hydrogen and nitrogen species and thus weakened the N≡N bond.


Ammonia synthesis Ru-based catalyst Cerium oxide morphology Catalytic performance 



The authors acknowledge the financial support of the Natural Science Foundation of China (Grant No. 21671147), Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi, State Key Laboratory of Coal and CBM Co-mining (Grant No. 2016012004).

Supplementary material

10562_2019_2674_MOESM1_ESM.docx (1.5 mb)
Supplementary material 1 (DOCX 1535 KB)


  1. 1.
    Kitano M, Kanbara S, Inoue Y, Kuganathan N, Sushko PV, Yokoyama T, Hara M, Hosono H (2015) Electride support boosts nitrogen dissociation over ruthenium catalyst and shifts the bottleneck in ammonia synthesis. Nat commun 6:6731–6739CrossRefGoogle Scholar
  2. 2.
    Song Z, Cai T, Hanson JC, Rodriguez JA, Hrbek J (2004) Structure and reactivity of Ru nanoparticles supported on modified graphite surfaces: a study of the model catalysts for ammonia synthesis. J Am Chem Soc 126:8576–8584CrossRefGoogle Scholar
  3. 3.
    Lu Y, Li J, Tada T, Toda Y, Ueda S, Yokoyama T, Kitano M, Hosono H (2016) Water durable electride Y5Si3: electronic structure and catalytic activity for ammonia synthesis. J Am Chem Soc 138:3970–3973CrossRefGoogle Scholar
  4. 4.
    Bielawa H, Hinrichsen O, Birkner A, Muhler M (2001) The ammonia-synthesis catalyst of the next generation: barium-promoted oxide-supported ruthenium. Angew Chem Int Ed 40:1061–1063CrossRefGoogle Scholar
  5. 5.
    Shi W, Liu X, Zeng J, Wang J, Wei Y, Zhu T (2016) Gas-solid catalytic reactions over ruthenium-based catalysts. Chin J Catal 37:1181–1192CrossRefGoogle Scholar
  6. 6.
    Kitano M, Inoue Y, Sasase M, Kishida K, Kobayashi Y, Nishiyama K, Tada T, Kawamura S, Yokoyama T, Hara M (2018) Self-organized ruthenium-barium core-shell nanoparticles on a mesoporous calcium amide matrix for efficient low-temperature ammonia synthesis. Angew Chem 130:2678–2682CrossRefGoogle Scholar
  7. 7.
    Aika K-i (2016) Role of alkali promoter in ammonia synthesis over ruthenium catalysts-effect on reaction mechanism. Catal Today 286:14–20CrossRefGoogle Scholar
  8. 8.
    Lin B, Wei K, Ma X, Lin J, Ni J (2013) Study of potassium promoter effect for Ru/AC catalysts for ammonia synthesis. Catal Sci Technol 3:1367–1374CrossRefGoogle Scholar
  9. 9.
    Lin B, Guo Y, Cao C, Ni J, Lin J, Jiang L (2018) Carbon support surface effects in the catalytic performance of Ba-promoted Ru catalyst for ammonia synthesis. Catal Today 316:230–236CrossRefGoogle Scholar
  10. 10.
    Chen M, Yuan M, Li J, You Z (2018) Ammonia synthesis over Cs- or Ba-promoted ruthenium catalyst supported on strontium niobate. Appl Catal A 554:1–9CrossRefGoogle Scholar
  11. 11.
    Lin B, Qi Y, Wei K, Lin J (2014) Effect of pretreatment on ceria-supported cobalt catalyst for ammonia synthesis. RSC Adv 4:38093–38102CrossRefGoogle Scholar
  12. 12.
    Inoue Y, Kitano M, Kim S-W, Yokoyama T, Hara M, Hosono H (2014) Highly dispersed RU on Electride [Ca24Al28O64]4+(e)4 as a catalyst for ammonia synthesis. ACS Catal 4:674–680CrossRefGoogle Scholar
  13. 13.
    Hara M, Kitano M, Hosono H (2017) Ru-loaded C12A7: e electride as a catalyst for ammonia synthesis. ACS Catal 7:2313–2324CrossRefGoogle Scholar
  14. 14.
    Inoue Y, Kitano M, Kishida K, Abe H, Niwa Y, Sasase M, Fujita Y, Ishikawa H, Yokoyama T, Hara M, Hosono H (2016) Efficient and stable ammonia synthesis by self-organized flat Ru nanoparticles on calcium amide. ACS Catal 6:7577–7584CrossRefGoogle Scholar
  15. 15.
    Abe H, Niwa Y, Kitano M, Inoue Y, Sasase M, Nakao T, Tada T, Yokoyama T, Hara M, Hosono H (2017) Anchoring bond between Ru and N atoms of Ru/Ca2NH catalyst: crucial for the high ammonia synthesis activity. J Phys Chem C 121:20900–20904CrossRefGoogle Scholar
  16. 16.
    Kitano M, Inoue Y, Yamazaki Y, Hayashi F, Kanbara S, Matsuishi S, Yokoyama T, Kim S-W, Hara M, Hosono H (2012) Ammonia synthesis using a stable electride as an electron donor and reversible hydrogen store. Nat Chem 4:934–940CrossRefGoogle Scholar
  17. 17.
    Nishi M, Chen S-Y, Takagi H (2018) A mesoporous carbon-supported and Cs-promoted Ru catalyst with enhanced activity and stability for sustainable ammonia synthesis. ChemCatChem 10:3411–3414CrossRefGoogle Scholar
  18. 18.
    Saito M, Itoh M, Iwamoto J, Li C-Y, Machida K-i (2006) Synergistic effect of MgO and CeO2 as a support for ruthenium catalysts in ammonia synthesis. Catal Lett 106:107–110CrossRefGoogle Scholar
  19. 19.
    Xie D, Sun Y, Zhu T, Fan X, Hong X, Yang W (2016) Ammonia synthesis and by-product formation from H2O, H2 and N2 by dielectric barrier discharge combined with an Ru/Al2O3 catalyst. RSC Adv 6:105338–105346CrossRefGoogle Scholar
  20. 20.
    Jacobsen CJH (2001) Boron nitride: a novel support for ruthenium-based ammonia synthesis catalysts. J Catal 200:1–3CrossRefGoogle Scholar
  21. 21.
    Ma Z, Xiong X, Song C, Hu B, Zhang W (2016) Electronic metal–support interactions enhance the ammonia synthesis activity over ruthenium supported on Zr-modified CeO2 catalysts. RSC Adv 6:51106–51110CrossRefGoogle Scholar
  22. 22.
    Sato K, Imamura K, Kawano Y, Miyahara S-i, Yamamoto T, Matsumura S, Nagaoka K (2017) A low-crystalline ruthenium nano-layer supported on praseodymium oxide as an active catalyst for ammonia synthesis. Chem Sci 8:674–679CrossRefGoogle Scholar
  23. 23.
    Luo X, Wang R, Ni J, Lin J, Lin B, Xu X, Wei K (2009) Effect of La2O3 on Ru/CeO2-La2O3 catalyst for ammonia synthesis. Catal Lett 133:382–387CrossRefGoogle Scholar
  24. 24.
    Lin J, Zhang L, Wang Z, Ni J, Wang R, Wei K (2013) The effect of Ag as a promoter for Ru/CeO2 catalysts in ammonia synthesis. J Mol Catal A 366:375–379CrossRefGoogle Scholar
  25. 25.
    Guo T, Du J, Li J (2016) The effects of ceria morphology on the properties of Pd/ceria catalyst for catalytic oxidation of low-concentration methane. J Mater Sci 51:10917–10925CrossRefGoogle Scholar
  26. 26.
    Ma L, Seo CY, Nahata M, Chen X, Li J, Schwank JW (2018) Shape dependence and sulfate promotion of CeO2 for selective catalytic reduction of NOx with NH3. Appl Catal B 232:246–259CrossRefGoogle Scholar
  27. 27.
    Huang H, Dai Q, Wang X (2014) Morphology effect of Ru/CeO2 catalysts for the catalytic combustion of chlorobenzene. Appl Catal B 158–159:96–105CrossRefGoogle Scholar
  28. 28.
    Wang S, Zhao L, Wang W, Zhao Y, Zhang G, Ma X, Gong J (2013) Morphology control of ceria nanocrystals for catalytic conversion of CO2 with methanol. Nanoscale 5:5582–5588CrossRefGoogle Scholar
  29. 29.
    Tan H, Wang J, Yu S, Zhou K (2015) Support morphology-dependent catalytic activity of Pd/CeO2 for formaldehyde oxidation. Environ Sci Technol 49:8675–8682CrossRefGoogle Scholar
  30. 30.
    Lykaki M, Pachatouridou E, Carabineiro SAC, Iliopoulou E, Andriopoulou C, Kallithrakas-Kontos N, Boghosian S, Konsolakis M (2018) Ceria nanoparticles shape effects on the structural defects and surface chemistry: implications in CO oxidation by Cu/CeO2 catalysts. Appl Catal B 230:18–28CrossRefGoogle Scholar
  31. 31.
    Lin B, Liu Y, Heng L, Ni J, Lin J, Jiang L (2017) Effect of ceria morphology on the catalytic activity of Co/CeO2 catalyst for ammonia synthesis. Catal Commun 101:15–19CrossRefGoogle Scholar
  32. 32.
    Lin B, Liu Y, Heng L, Wang X, Ni J, Lin J, Jiang L (2018) Morphology effect of ceria on the catalytic performances of Ru/CeO2 catalysts for ammonia synthesis. Ind Eng Chem Res 57:9127–9135CrossRefGoogle Scholar
  33. 33.
    Ma Z, Zhao S, Pei X, Xiong X, Hu B (2017) New insights into the support morphology-dependent ammonia synthesis activity of Ru/CeO2 catalysts. Catal Sci Technol 7:191–199CrossRefGoogle Scholar
  34. 34.
    Amar IA, Lan R, Tao S (2015) Synthesis of ammonia directly from wet nitrogen using a redox stable La0.75Sr0.25Cr0.5Fe0.5O3−δ-Ce0.8Gd0.18Ca0.02O2−δ composite cathode. RSC Adv 5:38977–38983CrossRefGoogle Scholar
  35. 35.
    Hansen TW, Hansen PL, Dahl S, Jacobsen CJ (2002) Support effect and active sites on promoted ruthenium catalysts for ammonia synthesis. Catal lett 84:7–12CrossRefGoogle Scholar
  36. 36.
    Saadatjou N, Jafari A, Sahebdelfar S (2014) Ruthenium nanocatalysts for ammonia synthesis: a review. Chem Eng Commun 202:420–448CrossRefGoogle Scholar
  37. 37.
    Izumi Y, Iwata Y, Aika K-i (1996) Catalysis on ruthenium clusters supported on CeO2 or Ni-doped CeO2: adsorption behavior of H2 and ammonia synthesis. J Phys Chem 100:9421–9428CrossRefGoogle Scholar
  38. 38.
    Dupin J-C, Gonbeau D, Vinatier P, Levasseur A (2000) Systematic XPS studies of metal oxides, hydroxides and peroxides. Phys Chem Chem Phys 2:1319–1324CrossRefGoogle Scholar
  39. 39.
    Nolan M (2011) Enhanced oxygen vacancy formation in ceria (111) and (110) surfaces doped with divalent cations. J Mater Chem 21:9160–9168CrossRefGoogle Scholar
  40. 40.
    Fernández C, Sassoye C, Debecker DP, Sanchez C, Ruiz P (2014) Effect of the size and distribution of supported Ru nanoparticles on their activity in ammonia synthesis under mild reaction conditions. Appl Catal A 474:194–202CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Shanxi Key Laboratory of Gas Energy Efficient and Clean UtilizationTaiyuan University of TechnologyTaiyuanPeople’s Republic of China
  2. 2.College of Environmental Science and EngineeringTaiyuan University of TechnologyJinzhongPeople’s Republic of China

Personalised recommendations