Room-Temperature Activation of H2 by a Surface Frustrated Lewis Pair

Surface frustrated Lewis pairs (SFLPs) have been implicated in the gas-phase heterogeneous (photo)catalytic hydrogenation of CO2 to CO and CH3OH by In2O3-x(OH)(y). A key step in the reaction pathway is envisioned to be the heterolysis of H-2 on a proximal Lewis acid-Lewis base pair, the SFLP, the chemistry of which is described as In...In-OH + H-2 -> In-OH2+...In-H-. The product of the heterolysis, thought to be a protonated hydroxide Lewis base In-OH2+ and a hydride coordinated Lewis acid In-H-, can react with CO2 to form either CO or CH3OH. While the experimental and theoretical evidence is compelling for heterolysis of H-2 on the SFLP, all conclusions derive from indirect proof, and direct observation remains lacking. Unexpectedly, we have discovered rhombohedral In2O3-x(OH)(y) can enable dissociation of H-2 at room temperature, which allows its direct observation by several analytical techniques. The collected analytical results lean towards the heterolysis rather than the homolysis reaction pathway.