Hydroxyl-mediated ethanol selectivity of CO(2) hydrogenation

Oxide-supported Rh nanoparticles have been widely used for CO(2) hydrogenation, especially for ethanol synthesis. However, this reaction operates under high pressure, up to 8 MPa, and suffers from low CO(2) conversion and alcohol selectivity. This paper describes the crucial role of hydroxyl groups bound on Rh-based catalysts supported on TiO(2) nanorods (NRs). The RhFeLi/TiO(2) NR catalyst shows superior reactivity (≈15% conversion) and ethanol selectivity (32%) for CO(2) hydrogenation. The promoting effect can be attributed to the synergism of high Rh dispersion and high-density hydroxyl groups on TiO(2) NRs. Hydroxyls are proven to stabilize formate species and protonate methanol, which is easily dissociated into *CH(x), and then CO obtained from the reverse water–gas shift reaction (RWGS) is inserted into *CH(x) to form CH(3)CO*, followed by CH(3)CO* hydrogenation to ethanol.