1 Department of Chemistry, Technical University of Denmark2 Department of Physics, Technical University of Denmark3 Center for Nanoteknologi, Center, Technical University of Denmark4 Centre for Catalysis and Sustainable Chemistry, Department of Chemistry, Technical University of Denmark5 unknown6 Department of Chemical and Biochemical Engineering, Technical University of Denmark7 Center for Atomic-scale Materials Design, Center, Technical University of Denmark
Here, we give a full account of a large collaborative effort toward an atomic-scale understanding of modern industrial ammonia production over ruthenium catalysts. We show that overall rates of ammonia production can be determined by applying various levels of theory (including transition state theory with or without tunneling corrections, and quantum dynamics) to a range of relevant elementary reaction steps, such as N(2) dissociation, H(2) dissociation, and hydrogenation of the intermediate reactants. A complete kinetic model based on the most relevant elementary steps can be established for any given point along an industrial reactor, and the kinetic results can be integrated over the catalyst bed to determine the industrial reactor yield. We find that, given the present uncertainties, the rate of ammonia production is well-determined directly from our atomic-scale calculations. Furthermore, our studies provide new insight into several related fields, for instance, gas-phase and electrochemical ammonia synthesis. The success of predicting the outcome of a catalytic reaction from first-principles calculations supports our point of view that, in the future, theory will be a fully integrated tool in the search for the next generation of catalysts.
Journal review article
Journal of Physical Chemistry Part B: Condensed Matter, Materials, Surfaces, Interfaces and Biophysical, 2006, Vol 110, Issue 36, p. 17719-17735