Details

Autor(en) / Beteiligte

• Mahdavi‐Shakib, Akbar
• Kumar, K. B. Sravan
• Whittaker, Todd N.
• Xie, Tianze
• Grabow, Lars C.
• Rioux, Robert M.
• Chandler, Bert D.

Titel

Kinetics of H2 Adsorption at the Metal–Support Interface of Au/TiO2 Catalysts Probed by Broad Background IR Absorbance

Ist Teil von

• Angewandte Chemie International Edition, 2021-03, Vol.60 (14), p.7735-7743

Auflage

International ed. in English

Ort / Verlag

Weinheim: Wiley Subscription Services, Inc

Erscheinungsjahr

2021

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• H2 adsorption on Au catalysts is weak and reversible, making it difficult to quantitatively study. We demonstrate H2 adsorption on Au/TiO2 catalysts results in electron transfer to the support, inducing shifts in the FTIR background. This broad background absorbance (BBA) signal is used to quantify H2 adsorption; adsorption equilibrium constants are comparable to volumetric adsorption measurements. H2 adsorption kinetics measured with the BBA show a lower Eapp value (23 kJ mol−1) for H2 adsorption than previously reported from proxy H/D exchange (33 kJ mol−1). We also identify a previously unreported H‐O‐H bending vibration associated with proton adsorption on electronically distinct Ti‐OH metal‐support interface sites, providing new insight into the nature and dynamics of H2 adsorption at the Au/TiO2 interface. FTIR studies during H2 activation over Au/TiO2 present clear spectroscopic evidence of H2 activation between Au and Ti‐OH groups at the metal–support interface. Electron transfer to the support shifts the broad background absorbance (BBA), enabling the differentiation of activation barriers forH2(D2) adsorption and surface (Ti‐OH) H/D exchange.