In a study published in Molecular Catalysis researchers from West Pomeranian University of Technology in Szczecin, Warsaw University of Technology, Graz University of Technology, and National Synchrotron Radiation Centre SOLARIS explored the structure of next-generation catalysts for ammonia synthesis. Only the combination of standard laboratory measurements with possibilities of synchrotron XANES/EXAFS allowed understanding mechanisms leading to the active form of the synthesised material.
To meet the demand from agriculture, the ammonia industry consumes ca. 2% of world energy production, which is a consequence of the high temperature (400-500°C) and high pressure (10-30 MPa) required for the Haber-Bosch process ongoing on widely used iron-based catalysts. The development of new-generation catalysts is essential to lower the operating costs and reduce the CO2 emission of this process. Ammonia is also positioned as a potential form of synthetic fuel of the future. As a result, research and development initiatives focusing on the production of so-called green ammonia, which is produced using hydrogen from water electrolysis powered by renewable energy sources, are gaining momentum.
Development of the new catalyst is high-throughput work, based on screening tests, which allow for the selection of e.g. the optimal carrier, deposition method of the active phase, and load of the active phase. After several dozens of tests, we have designed a promising new catalyst, obtained by impregnation of the γ-Al2O3 with the cobalt and molybdenum compounds, followed by the activation process. The catalytic activity and stability of the obtained catalysts, tested in a laboratory fixed bed reactor under atmospheric pressure at 500 °C, were promising compared to the reference state-of-art Co3Mo3N and the commercial iron-based catalyst. However, the determination of the active phase structure, necessary to fully understand the nature of the catalyst, with standard laboratory methods was ambiguous. Thus, selected obtained catalysts were examined with the help of powerful synchrotron XANES/EXAFS measurements at the ASTRA beamline.
Read more on SOLARIS website
Image: Scheme of the catalyst synthesis protocol including wet impregnation of support and activation of precursor in ammonia, resulting in highly active and stable catalyst.