Influence of phosphate addition on activity of Ag and Cu catalysts for partial oxidation of alcohols

Phosphate-containing silica-supported silver and copper catalysts prepared by impregnation method were investigated using TEM, H2 TPR and CO TPR methods and tested in the reaction of selective ethylene glycol oxidation into glyoxal. It was shown that reversible oxidation–reduction of the active component took place in case of Ag- and Cu-containing catalysts. In case of Cu-containing systems formation of copper oxides on the catalyst surface led to the decrease in catalytic activity. Silver oxide-like species did not form in the presence of phosphate modifier on the surface of Ag-containing systems, and that led to the increase in glyoxal selectivity during ethylene glycol oxidation.