Fundamental understanding of the role of potassium on the activity of Pt/CeO₂ for the hydrogen production from ethanol

The effect of potassium as a promoter on the activity of Pt/CeO₂ catalysts for hydrogen production from ethanol was studied in this work. The Pt/CeO₂ catalysts with or without potassium were prepared with incipient impregnation method and analyzed using synchrotron-based X-ray diffraction (XRD), X-ray absorption near-edge spectroscopy (XANES), oxygen adsorption, ethanol temperature programmed desorption (TPD) NH₃-TPD, and TPR. We find that Pt particles on all CeO₂-based catalysts were less than 2 nm. Potassium addition did not have benefit on hydrogen production activity. However, potassium modified active sites, acidity, and interaction between Pt and CeO₂. Oxygen storage capacity (OSC) was decreased, while the acidity was neutralized and the interaction between Pt and CeO ₂ was weakened when potassium was added to Pt/CeO₂. Potassium promoted ethanol decomposition reaction while inhibited decarbonylation of acetaldehyde and CH₄ formation. This work confirms our previous finding that Pt-CeO₂ synergistic interaction played an important role for hydrogen production from bio-alcohols.