Operando XAFS of supported Pd nanoparticles in flowing ethanol/water mixtures: implications for catalysisElectronic supplementary information (ESI) available: Catalyst synthesis, operando EXAFS measurements, linear combination analyses, transmission electron microscopy, comparison of 1, 2, and 5 wt% Pd systems. See DOI: 10.1039/c5gc01600b

Ethanol-water, a prototypical 'green' solvent mixture, cannot be considered as inert toward supported Pd nanoparticles. We establish severe size dependencies in Pd redox behavior, persistent gradients in Pd phase in a plug-flow situation, and that Pd nanoparticles are contaminated with hydrogen derived from the solvent. Ethanol-water, a prototypical 'green' solvent mixture, cannot be considered as inert toward supported Pd nanoparticles.