On Optimal Barium Promoter Content in a Cobalt Catalyst for Ammonia Synthesis

High priority in developing an efficient cobalt catalyst for ammonia synthesis involves optimizing its composition in terms of the content of promoters. In this work, a series of cobalt catalysts doubly promoted with cerium and barium was prepared and tested in ammonia synthesis (H2/N2 = 3, 6.3 MPa, 400 °C). Barium content was studied in the range of 0–2.6 mmol gCo−1. Detailed characterization studies by nitrogen physisorption, SEM-EDX, XRPD, H2-TPR, and H2-TPD showed the impact of barium loading in CoCeBa catalysts on the physicochemical properties and activity of the catalysts. The most pronounced effect was observed in the development of the active phase surface, a differentiation of weakly and strongly binding sites on the catalyst surface and changes in cobalt surface activity (TOF). Barium content in the range of 1.1–1.6 mmol gCo−1 leads to obtaining a catalyst with the most favorable properties. Its excellent catalytic performance is ascribed to the appropriate Ba/Ce molar ratio, i.e., greater than unity, which results in not only a structural promotion of barium, but also a modifying action associated with the in-situ formation of the BaCeO3 phase.

[1]  Hubert Ronduda,et al.  Development of cobalt catalyst supported on MgO–Ln2O3 (Ln = La, Nd, Eu) mixed oxide systems for ammonia synthesis , 2021, International Journal of Hydrogen Energy.

[2]  Lilong Jiang,et al.  Sacrificial Sucrose Strategy Achieved Enhancement of Ammonia Synthesis Activity over a Ceria-Supported Ru Catalyst , 2021, ACS Sustainable Chemistry & Engineering.

[3]  Hubert Ronduda,et al.  A high performance barium-promoted cobalt catalyst supported on magnesium–lanthanum mixed oxide for ammonia synthesis , 2021, RSC advances.

[4]  Hubert Ronduda,et al.  On the Effect of Flash Calcination Method on the Characteristics of Cobalt Catalysts for Ammonia Synthesis Process , 2021 .

[5]  Katsutoshi Sato,et al.  Barium Oxide Encapsulating Cobalt Nanoparticles Supported on Magnesium Oxide: Active Non-noble Metal Catalyst for Ammonia Synthesis under Mild Reaction Condition , 2021, ACS Catalysis.

[6]  Hubert Ronduda,et al.  Kinetic studies of ammonia synthesis over a barium-promoted cobalt catalyst supported on magnesium–lanthanum mixed oxide , 2020 .

[7]  Hubert Ronduda,et al.  Synergistic Interaction of Cerium and Barium-New Insight into the Promotion Effect in Cobalt Systems for Ammonia Synthesis , 2020, Catalysts.

[8]  Hubert Ronduda,et al.  Surface enrichment phenomenon in the Ba-doped cobalt catalyst for ammonia synthesis , 2019, Vacuum.

[9]  H. Takagi,et al.  Mild Ammonia Synthesis over Ba-Promoted Ru/MPC Catalysts: Effects of the Ba/Ru Ratio and the Mesoporous Structure , 2019, Catalysts.

[10]  M. Zybert,et al.  Effect of precipitating agent on the properties of cobalt catalysts promoted with cerium and barium for NH3 synthesis obtained by co-precipitation , 2017 .

[11]  M. Zybert,et al.  Effect of a Barium Promoter on the Stability and Activity of Carbon‐Supported Cobalt Catalysts for Ammonia Synthesis , 2015 .

[12]  M. Twigg,et al.  Thermal decomposition of bulk and supported barium nitrate , 2015 .

[13]  M. Zybert,et al.  Thermal analysis coupled with mass spectrometry as a tool to determine the cobalt content in cobalt catalyst precursors obtained by co-precipitation , 2014 .

[14]  W. Raróg-Pilecka,et al.  Ammonia synthesis over cobalt catalysts doped with cerium and barium. Effect of the ceria loading , 2012 .

[15]  W. Raróg-Pilecka,et al.  Cobalt Catalyst Doped with Cerium and Barium Obtained by Co-Precipitation Method for Ammonia Synthesis Process , 2011 .

[16]  W. Raróg-Pilecka,et al.  Barium-promoted Ru/carbon catalyst for ammonia synthesis: State of the system when operating , 2009 .

[17]  Su Ha,et al.  Metallic phases of cobalt-based catalysts in ethanol steam reforming: The effect of cerium oxide , 2009 .

[18]  Y. Teraoka,et al.  Catalytic decomposition of N2O over CeO2 promoted CO3O4 spinel catalyst , 2007 .

[19]  Yu‐Wen Chen,et al.  The mechanism of reduction of cobalt by hydrogen , 2004 .

[20]  W. Raróg-Pilecka,et al.  Carbon-based ruthenium catalyst for ammonia synthesis: Role of the barium and caesium promoters and carbon support , 2003 .

[21]  C. Jacobsen,et al.  Ammonia synthesis with barium-promoted iron–cobalt alloys supported on carbon , 2003 .

[22]  S. Dahl,et al.  Support Effect and Active Sites on Promoted Ruthenium Catalysts for Ammonia Synthesis , 2002 .

[23]  K. Aika,et al.  The Working State of the Barium Promoter in Ammonia Synthesis over an Active-Carbon-Supported Ruthenium Catalyst Using Barium Nitrate as the Promoter Precursor , 2002 .

[24]  S. Dahl,et al.  Atomic-Resolution in Situ Transmission Electron Microscopy of a Promoter of a Heterogeneous Catalyst , 2001, Science.

[25]  G. Hutchings.  Promotion in Heterogeneous Catalysis: A Topic Requiring a New Approach? , 2001 .

[26]  M. Muhler,et al.  The Ammonia-Synthesis Catalyst of the Next Generation: Barium-Promoted Oxide-Supported Ruthenium. , 2001, Angewandte Chemie.

[27]  I. Rossetti,et al.  Promoters effect in Ru/C ammonia synthesis catalyst , 2001 .

[28]  J. Sentek,et al.  Effect of K, Cs and Ba on the kinetics of NH3 synthesis over carbon-based ruthenium catalysts , 2000 .

[29]  I. Rossetti,et al.  Carbon-supported promoted Ru catalyst for ammonia synthesis , 1999 .

[30]  Zhi-hua Zhong,et al.  The Effect of Hydrogen Treatment of Active Carbon on Ru Catalysts for Ammonia Synthesis , 1998 .

[31]  Y. Izumi,et al.  Molecular sensing techniques for the characterization and design of new ammonia catalysts , 1997 .

[32]  T. Paryjczak,et al.  An alkali-promoted ruthenium catalyst for the synthesis of ammonia, supported on thermally modified active carbon , 1997 .

[33]  Z. Kowalczyk.  Effect of potassium on the high pressure kinetics of ammonia synthesis over fused iron catalyst , 1996 .

[34]  P. Stoltze.  Structure and Surface Chemistry of Industrial Ammonia Synthesis Catalysts , 1995 .

[35]  G. Somorjai,et al.  The effects of potassium on ammonia synthesis over iron single-crystal surfaces , 1988 .

[36]  G. Ertl,et al.  Adsorption of nitrogen on potassium promoted Fe(111) and (100) surfaces , 1982 .

[37]  K. Aika,et al.  Activation of nitrogen by alkali metal promoted transition metal I. Ammonia synthesis over ruthenium promoted by alkali metal , 1972 .

[38]  M. Muhler,et al.  The Kinetics of Ammonia Synthesis over Ruthenium-Based Catalysts: The Role of Barium and Cesium , 2002 .

[39]  Howard F. Rase,et al.  Handbook of Commercial Catalysts: Heterogeneous Catalysts , 2000 .

[40]  K. Tamaru.  The History of the Development of Ammonia Synthesis , 1991 .

[41]  C. H. Bartholomew,et al.  The stoichiometries of H2 and CO adsorptions on cobalt: Effects of support and preparation , 1984 .