Active surface formation and catalytic activity of phosphorous-promoted electrolytic silver in the selective oxidation of ethylene glycol to glyoxal

• Published in: Applied catalysis. A, General Vol. 344; no. 1; pp. 142 - 149
• Main Authors: Magaev, O.V., Knyazev, A.S., Vodyankina, O.V., Dorofeeva, N.V., Salanov, A.N., Boronin, A.I.
• Format: Journal Article
• Language: English; Russian
• Published: Amsterdam Elsevier B.V 15.07.2008; Elsevier
• Subjects: Active surface formation; Electrolytic silver catalyst; Ethylene glycol oxidation; Glyoxal; Phosphorous-containing promoter; Active surface formation; Glyoxal; Electrolytic silver catalyst; Ethylene glycol oxidation; Phosphorous-containing promoter
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/j.apcata.2008.04.007

P-containing electrolytic silver catalysts have been investigated in the partial oxidation of ethylene glycol (EG). It was shown that the addition of the phosphorus-containing promoter on the surface of electrolytic Ag catalyst led to the growth of glyoxal (GO) yield up to 15–20% mass. The glyoxal selectivity rise is explained by the absence of low temperature oxygen forms in temperature-programmed desorption (TPD) spectra. ▪ Unpromoted and phosphorus-promoted electrolytic silver catalysts have been investigated in the partial oxidation of ethylene glycol (EG). It was shown that the addition of the phosphorus-containing promoter on the surface of electrolytic Ag catalyst led to 15–20% increase in glyoxal (GO) yield. The formation mechanism of the active P-containing surfaces of silver catalyst as well as polycrystalline Ag foil has been studied by means of X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption (TPD) and scanning electron microscopy (SEM) methods. It was shown that silver clusters located nearby the P-containing Ag surface participate in the ethylene glycol oxidation into glyoxal. The rise of glyoxal selectivity is explained by the absence of low temperature peak at 250 °C in TPD spectra of both P-promoted Ag foil and electrolytic Ag catalysts. This peak was assigned to the decomposition of surface oxide-like species (Ag 2 sO) responsible for deep oxidation of ethylene glycol.