Understanding the Facile Heterolytic Dissociation of Hydrogen on Natural Surface Frustrated Lewis Pairs

The discovery of naturally frustrated Lewis pairs (FLPs) on wurtzite-structured surfaces provides a shortcut to obtain dense and stable surface FLPs without complex surface engineering. However, the catalytic performance and potential applications in the catalysis of natural FLPs have not been thoroughly investigated. Herein, the heterolytic dissociation of hydrogen is studied at the natural FLPs of wurtzite-structured GaN, ZnO, and SiC surfaces by using theoretical methods. Compared with classical Lewis pairs (CLPs), the FLPs show lower activation barriers ranging from 0.07 to 0.16 eV but higher reaction energies in the heterolytic dissociation of hydrogen. By splitting the energy into different items via a chemical–physical model, the optimal substrate–surface interaction and the decreasing stability of lone pair electrons on N atoms are recognized as the main reason for the lower activation energy and the higher reaction energy at FLPs, respectively. Because of the relatively favorable kinetics and unfavorable thermodynamics in hydrogen dissociation, FLPs present superior performance in the selective hydrogenation of acetylene to ethylene, reflected by the lower activation energy by 0.89 eV in the rate-determining step than CLPs. Overall, this study not only provides mechanistic insights into the heterolytic dissociation of hydrogen at FLPs but also unfolds the advantages of FLPs in hydrogenation reactions.