Electrochemical and UV-visible spectroscopy studies of K6AS2W_(18-x)Mo_xO_y2 (x = 0-3) Wells-Dawson heteropolyacid catalysts for oxidative dehydrogenation of benzyl alcohol

摘要

Redox behaviors of molybdenum-substituted Wells-Dawson tungstoarsenate heteropolyacid catalysts (α-K6As2W_(18-x)Mo_xO62 (x = 0-3)) were probed by electrochemical and UV-visible spectroscopy measurements. Reduction potential of K6As2W_(18-x)Mo_xO_(62) (x = 0-3) catalysts shifted to more positive potential with increasing molybdenum content UV-visible spectroscopy analysis was conducted as a simple diagnostic method for reduction potential. Absorption edge energy determined by UV-visible spectroscopy decreased with increasing reduction potential. Gas-phase oxidative dehydrogenation of benzyl alcohol was carried out as a model reaction. Yield for benzaldehyde increased with increasing electrochemical reduction potential and with decreasing UV-visible absorption edge energy of the catalysts.