Effects of Cl on the reduction of supported PdO in ethanol/water solvent mixtures

DOI: 10.1080/2055074X.2016.1267296

Authors: John B. Brazier (Imperial College London) , Mark A. Newton (University of Warwick) , Elena M. Barreiro (Imperial College London) , Stephen Parry (Diamond Light Source) , Luis A. Adrio (Imperial College London) , Christopher J. Mulligan (Imperial College London) , Klaus Hellgardt (Imperial College London) , King Kuok (mimi) Hii (Imperial College London) , Paul B. J. Thompson (University of Liverpool; European Synchrotron Radiation Facility) , Rachel Nichols (University of Leeds) , Bao N. Nguyen (University of Leeds)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Catalysis, Structure & Reactivity , VOL 3 , PAGES 54 - 62

State: Published (Approved)
Published: February 2017
Diamond Proposal Number(s): 9584

Abstract: The reduction of γ-Al2O3-supported PdO in flowing aqueous ethanol was investigated. Quick EXAFS (QEXAFS) performed at the Pd K-edge reveals that the presence of Cl can have a profound effect on the reduction process. At low loadings of Pd (1 wt-%), the size dependency of the process is inverted, compared to Cl-free samples. The extent of reduction was found to be dependent on loading/particles size. It is shown, using in situ QEXAFS at the Cl K- and Pd L3-edges, that residual Cl is not removed by the flowing solvent mixture, even at an elevated temperature of 350 K. The origins of these behaviours are discussed in terms of the differing effects that Cl may have when bonded to oxidic or reduced metal centres and the results were compared to earlier observations made on the effects of Cl on commercial polyurea encapsulated Pd ENCAT™ NP 30 catalysts.

Journal Keywords: Quick EXAFS; chlorine; Palladium; green solvents; reduction; hydride formation; operando measurement

Subject Areas: Chemistry, Materials


Instruments: B18-Core EXAFS

Other Facilities: ESRF