Photoassisted Selective Steam and Dry Reforming of Methane to Syngas Catalyzed by Rhodium-Vanadium Bimetallic Oxide Cluster Anions at Room Temperature.

Photoassisted steam reforming and dry (CO ) reforming of methane (SRM and DRM) at room temperature with high syngas selectivity have been achieved in the gas-phase catalysis for the first time. The catalysts used are bimetallic rhodium-vanadium oxide cluster anions of Rh VO . Both the oxidation of methane and reduction of H O/CO can take place efficiently in the dark while the pivotal step to govern syngas selectivity is photo-excitation of the reaction intermediates Rh VO CH to specific electronically excited states that can selectively produce CO and H . Electronic excitation over Rh VO CH to control the syngas selectivity is further confirmed from the comparison with the thermal excitation of Rh VO CH , which leads to diversity of products. The atomic-level mechanism obtained from the well-controlled cluster reactions provides insight into the process of selective syngas production from the photocatalytic SRM and DRM reactions over supported metal oxide catalysts.