Speaker
Description
Most efficient heterogeneous catalysts used industrially are generally very complex systems. Far away from perfect crystallinity and well-defined oriented surfaces at low coverage, they involve structural disorder, heterogeneous site distribution with variable coordination and structural dependence upon the chemical environment. Unravelling their atomic-scale structures and understanding their roles in the catalytic reaction are not easy tasks, as the respective contributions of each type of site to the spectroscopic or catalytic responses are generally convoluted. Computational chemistry is of great help to address these issues, but very often, simple structural models are proposed to understand catalytic reactions. In the present manuscript, we show how Density Functional Theory (DFT) calculations were used to provide an original information about the structure for active sites of complex catalytic systems of industrial relevance, as a function of their environment, to assign spectroscopic observations and to quantify the kinetics of multi-step reactions they can catalyze.[1] Heterogeneous catalysts involved in industrial applications such as refining, petrochemistry, biomass conversion and pollution abatement were considered. In particular, original models of imperfect aluminosilicates were developed and their Brønsted acidity unraveled.[2] The reactive environment-dependent (hydrogen and hydrocarbons) morphology of subnanometric platinum-based clusters was revealed.[3] Finally, we show how ab initio thermodynamic and kinetic information can be introduced in kinetic models, possibly integrated themselves in Computational Fluid Simulations, to access macroscopic predictions thanks to a multiscale approach.[4]
References
[1] C. Chizallet, P. Raybaud, Catal. Sci. Technol. 2014, 4, 2797.
[2] C. Chizallet, P. Raybaud, Angew. Chem. Int. Ed. 2009, 48, 2891 ; F. Leydier, C. Chizallet, D. Costa, P. Raybaud, J. Catal. 2015, 325 ; M.-C. Silaghi, C. Chizallet, J. Sauer, P. Raybaud, J. Catal. 2016, 339, 242.
[3] C. Mager-Maury, G. Bonnard, C. Chizallet, P. Sautet, P. Raybaud, ChemCatChem 2011, 3, 200 ; A. Gorczyca, V. Moizan, C. Chizallet, O. Proux, W. Del Net, E. Lahera, J. L. Hazemann, P. Raybaud, Y. Joly, Angew. Chem., Int. Ed 2014, 53, 12426.
[4] K. Larmier, A. Nicolle, C. Chizallet, N. Cadran, S. Maury, A.-F. Lamic-Humblot, E. Marceau, H. Lauron-Pernot, ACS Catalysis 2016, 6, 1905 ; K. Larmier, C. Chizallet, S. Maury, N. Cadran, J. Abboud, A. F. Lamic-Humblot, E. Marceau, H. Lauron-Pernot, Angew. Chem. Int. Ed. 2017, 56, 230.
