Paleček David, Tek Gökçen, Lan Jinggang, Iannuzzi Marcella, Hamm Peter
Department of Chemistry , University of Zurich , Zurich , Switzerland.
J Phys Chem Lett. 2018 Mar 15;9(6):1254-1259. doi: 10.1021/acs.jpclett.8b00310. Epub 2018 Feb 27.
The vibrational dynamics of Pt-H on a nanostructured platinum surface has been examined by ultrafast infrared spectroscopy. Three bands are observed at 1800, 2000, and 2090 cm, which are assigned to Pt-CO in a bridged and linear configuration and Pt-H, respectively. Lifetime analysis revealed a time constant of (0.8 ± 0.1) ps for the Pt-H mode, considerably shorter than that of Pt-CO because of its stronger coupling to the metal substrate. Two-dimensional attenuated total reflection infrared spectroscopy provided additional evidence for the assignment based on the anharmonic shift, which is large in the case of Pt-H (90 cm), in agreement with the density functional theory calculations. The absorption cross section of Pt-H is smaller than that of the very strong Pt-CO vibration by only a modest factor of ∼1.5-3. Because Pt-H is transiently involved in catalytic water splitting on Pt, the present spectroscopic characterization paves the way for in-operando kinetic studies of such reactions.
