A Heterogeneous Metal-Free Catalyst for Hydrogenation: Lewis Acid-Base Pairs Integrated into a Carbon Lattice

Designing heterogeneous metal-free catalysts for hydrogenation is a long-standing challenge in catalysis. Nanodiamond-based carbon materials were prepared that are surface-doped with electron-rich nitrogen and electron-deficient boron. The two heteroatoms are directly bonded to each other to form unquenched Lewis pairs with infinite π-electron donation from the surrounding graphitic structure. Remarkably, these Lewis pairs can split H₂ to form H⁺ /H^- pairs, which subsequently serve as the active species for hydrogenation of different substrates. This unprecedented finding sheds light on the uptake of H₂ across carbon-based materials and suggests that dual Lewis acidity-basicity on the carbon surface may be used to heterogeneously activate a variety of small molecules.