Hibbitts, David D.; Loveless, Brett T.; Neurock, Matthew; Iglesia, Enrique

Angewandte Chemie, International Edition (2013), 52(47), 12273-12278 CODEN: ACIEF5; ISSN: 1433-7851. English.

The results of this research demonstrates that H2O, whether indigenous or co-fed, increases CO activation rates on Ru-based catalysts in a manner consistent with the involvement of H2O-mediated H-transfer routes and competitive adsorption of H2O-derived intermediates. DFT-derived reaction and activation energies indicate that H2O mediates the kinetically-relevant H-transfer required for O-H bond formation in pathways involving *HCOH* intermediates and increases chain growth probabilities by increasing the rate of monomer formation when growth occurs via CHx* or the rate constant for chain growth when CO* is the monomer. H2O can act as a cocatalyst in FTS reactions in doing so, as previously observed in metal-catalyzed hydrogenations in protic media. The kinetic resemblance among Ru and Co catalysts suggest that similar conclusions about H2O-mediated routes apply to FTS catalysis on Co, on which FTS rates and product chain length also increase with increasing H2O pressure.