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 In₂O_3?x(OH)_y. A key step in the reaction pathway is envisioned to be the heterolysis of H₂ on a proximal Lewis acid–Lewis base pair, the SFLP, the chemistry of which is described as In???In‐OH + H₂ → 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 H₂ on the SFLP, all conclusions derive from indirect proof, and direct observation remains lacking. Unexpectedly, we have discovered rhombohedral In₂O_3?x(OH)_y can enable dissociation of H₂ 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.