Room‐Temperature Activation of H 2 by a Surface Frustrated Lewis Pair

Abstract Surface frustrated Lewis pairs (SFLPs) have been implicated in the gas‐phase heterogeneous (photo)catalytic hydrogenation of CO 2 to CO and CH 3 OH by In 2 O 3− 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‐OH 2 + ⋅⋅⋅In‐H − . The product of the heterolysis, thought to be a protonated hydroxide Lewis base In‐OH 2 + and a hydride coordinated Lewis acid In‐H − , can react with CO 2 to form either CO or CH 3 OH. 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 In 2 O 3− 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.