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　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　In2O3−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.　©　2019　Wiley-VCH　Verlag　GmbH　&　Co.　KGaA,　Weinheim