| AVS 59th Annual International Symposium and Exhibition | |
| Surface Science | Thursday Sessions |
| Session SS+EN+OX-ThM |
| Session: | Catalysis and Photocatalysis on Oxides |
| Presenter: | J.F. Weaver, University of Florida |
| Authors: | J.F. Weaver, University of Florida A. Antony, University of Florida C. Hakanoglu, University of Florida F. Zhang, University of Florida A. Asthagiri, The Ohio State University |
| Correspondent: | Click to Email |
We have investigated initial C-H bond selectivity in the activation of propane and n-butane on PdO(101) both experimentally and computationally. Temperature-programmed experiments using different propane isotopologues reveal a strong preference toward primary C-H bond cleavage of propane on PdO(101); about 90% of the propane molecules which react do so by primary C-H bond activation. Direct measurements of the initial dissociation probability of various n-butane isotopologues also demonstrate a high selectivity for primary C-H bond activation of n-butane on PdO(101) at low coverages. Unlike propane, however, TPRS experiments show that the preference for primary C-H bond cleavage of n-butane diminishes with increasing molecular coverage. Calculations using dispersion-corrected DFT reproduce the selectivity toward primary C-H bond cleavage of propane and n-butane on PdO(101), and predict that alkane C-H bond scission occurs heterolytically on the oxide surface. The calculations suggest that greater substituent polarization in the 1-alkyl transition structures is responsible for the lower energy barriers for primary vs. secondary C-H bond activation of alkanes on PdO(101).