1. Dependence on Size of Supported Rh Nanoclusters in the Dehydrogenation of Methanol-d4 Obstructed by CO
- Author
-
Zhen He Liao, Meng Fan Luo, Jeng Han Wang, Po Wei Hsu, Kuan Ting Liu, and Guan Jr Liao
- Subjects
02 engineering and technology ,Reaction intermediate ,Activation energy ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,0104 chemical sciences ,Nanoclusters ,Catalysis ,chemistry.chemical_compound ,Adsorption ,chemistry ,Cluster (physics) ,General Materials Science ,Dehydrogenation ,Methanol ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
The size effect on the activity of a catalyst has been a focal issue since ideal catalysts were pursued, whereas that on the degradation of a catalyst, by reaction intermediates such as CO, is little discussed. We demonstrate that the dehydrogenation of methanol-d4 on supported Rh nanoclusters precovered with CO (Rh-CO clusters) was obstructed, indicated by a decreased production of CO and D2; the obstructive effect exhibits a remarkable dependence on the cluster size, with a minimum at a cluster diameter near 1.4 nm. The decreased production arose from a decreased reaction probability controlled by the increased activation energy for each dehydrogenation step (including formation of methoxy-d3), adsorption energies of CO, and repulsion from the CO array on the Rh-CO surface. The effects of these factors in deactivating the clusters varied separately with the cluster size. Consequently, the size effect on the CO poisoning should be taken into account in engineering the cluster size to optimize the catalytic performance.
- Published
- 2021
- Full Text
- View/download PDF