Frustrated Lewis Pair Catalysts in Two Dimensions: B/Al-Doped Phosphorenes as Promising Catalysts for Hydrogenation of Small Unsaturated Molecules

Using comprehensive density functional theory (DFT) computations, we designed two promising two-dimensional (2D) metal-free heterogeneous frustrated Lewis pair (FLP) catalysts for the hydrogenation of small unsaturated molecules (such as ketone, nitrile, and ethylene). The catalyst consists of a phosphorene monolayer that is doped with B or Al impurity to form a frustrated B/P or Al/P Lewis pair without the need for steric hindrance. The hydrogenations of ketones, nitrile, and ethylene on the B- or Al-doped phosphorene prefer to proceed through a two-step mechanism: the heterolytic dissociation of H2 molecule, followed by the concerted hydrogen transfer. This study not only identifies two promising catalysts, namely B/Al-doped phosphorenes, for the hydrogenations of small unsaturated molecules, but also provides a useful strategy to develop FLP catalysts in 2D materials.