Applications of molecular modeling in heterogeneous catalysis research

The application of molecular modeling in heterogeneous catalysis research as a complement to experimental studies has grown rapidly in recent years. This review summarizes methodologies for probing catalytic phenomena in terms of a hierarchical approach. The elements of the hierarchy are different computational methods at different time and length scales that may be linked together to answer questions spanning from the atomic to the macroscopic. At the most detailed level of description, quantum chemical calculations are used to predict the energies, electronic structures, and spectroscopic properties of small arrangements of atoms and even periodic structures. Atomistic simulations, using systems of hundreds or thousands of molecules, can be used to predict macroscopic thermodynamic and transport properties, as well as preferred molecular geometries. At the longest time and length scales, continuum engineering modeling approaches such as microkinetic modeling are used to calculate reaction rates, reactant conversion, and product yields and selectivities, using model parameters predicted by the other levels of the hierarchy. We highlight some interesting recent results for each of these approaches, stress the need for integrating modeling at widely varying time and length scales, and discuss current challenges and areas for future development.