Liquid-Phase Oxidation Of Ethylene Glycol On Pt And Pt-Fe Catalysts For The Production Of Glycolic Acid: Remarkable Bimetallic Effect And Reaction Mechanism

A highly active and selective Pt-Fe alloy catalyst on CeO2 support is reported in this work for aqueous phase oxidation of ethylene glycol (EG) to glycolic acid. The Pt-Fe nanoparticles are highly alloyed with a face-centered cubic (fcc) type of crystal structure and a chemical state of Pt-0/Fe-0, as confirmed from X-ray diffraction and extended X-ray absorption fine structure characterizations, respectively. Compared to the monometallic Pt catalyst, the Pt-Fe catalyst shows more than a 17-fold higher initial TOF, while achieving complete EG conversion in 4 h at 70 degrees C and ambient O-2 pressure under alkaline conditions. The synergistic bimetallic effect occurs due to significantly changing the O-2 adsorption-dissociation characteristics on the catalyst surface. The addition of a base shows a promotional effect on both Pt and Pt-Fe catalysts at low NaOH concentrations but an inhibition effect is observed for both catalysts at sufficiently high NaOH concentrations. Furthermore, the base enhances the synergistic effect observed with Pt-Fe catalyst.