Computational chemistry provides powerful research tools for catalysis. It potentially allows us to study the structures of the catalytic sites and reaction mechanisms, which are difficult to observe only by experiment. This is particularly true for supported heterogeneous catalysts, of which reactivity and catalytic behavior are directly related to the presence of various functional groups and reactive ensembles on their surfaces. Such surface heterogeneities give rise to the formation of multifunctional reactive ensembles ready to convert substrate molecules to the desired products efficiently. At the same time, the presence of various reactive centers on the surface may contribute to undesirable conversion paths. Understanding the role of the multifunctional reaction environments established on the complex surfaces of supported heterogeneous catalysts is key to formulating design rules for achieving control over their activity and selectivity....