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Unraveling the H2 promotional effect on the Palladium catalysed CO oxidation using a combination of temporally and spatially resolved investigations

DOI: 10.1021/acscatal.8b01509 DOI Help

Authors: Caomhan Stewart (Queen's University of Belfast) , Emma K. Gibson (University of Glasgow) , Kevin Morgan (Queen’s University Belfast) , Giannantonio Cibin (Diamond Light Source) , Andrew J. Dent (Diamond Light Source) , Christopher Hardacre (University of Manchester) , Evgenii V. Kondratenko (Universität Rostock) , Vita A. Kondratenko (Universität Rostock) , Colin Mcmanus (Queen’s University Belfast) , Scott Rogers (UK Catalysis Hub; University College London) , Cristina E. Stere (University of Manchester) , Sarayute Chansai (University of Manchester) , Yichi Wang (Universität Rostock) , Sarah J. Haigh (University of Manchester) , Peter P. Wells (UK Catalysis Hub; Diamond Light Source; University of Southampton) , Alexandre Goguet (Queen's University of Belfast)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Acs Catalysis

State: Published (Approved)
Published: July 2018
Diamond Proposal Number(s): 11747

Abstract: The promotional effect of H2 on the oxidation of CO is of topical interest and there is debate over whether this promotion is due to either thermal or chemical effects. As yet there is no definitive consensus in the literature. Combining spatially resolved mass spectrometry and X-ray absorption spectroscopy (XAS) we observe a specific environment of the active catalyst during CO oxidation, having the same specific local coordination of the Pd in both the absence and presence of H2. In combination with Temporal Analysis of Products (TAP), performed under isothermal conditions, a mechanistic insight into the promotional effect of H2 was found, providing clear evidence of non-thermal effects in the hydrogen promoted of oxidation of carbon monoxide. We have identified that H2 promotes the Langmuir Hinshelwood mechanism and we propose this is linked to the increased interaction of O with the Pd surface in the presence of H2. This combination of spatially resolved MS and XAS and TAP studies has provided previously unobserved insights into the nature of this promotional effect.

Journal Keywords: CO oxidation; TAP; XAFS; spatially resolved; SPACI-FB

Subject Areas: Chemistry

Instruments: B18-Core EXAFS