Elucidating the role of Cu species in the oxidative carbonylation of methanol to dimethyl carbonate on CuY: An in situ spectroscopic and catalytic study Original Research Article

CuY catalysts with varied Cu content obtained by incipient-wetness-impregnation of commercial NH4-Y zeolite with copper nitrate solution and calcination at 400 °C in air were examined by in situ FTIR investigations to characterize the Cu species and elucidate their specific role in the oxidative carbonylation of methanol. The adsorption of CO was applied to check the state of Cu(I) species whereas the acidity was characterized by pyridine adsorption. Depending on the Cu content different intensity ratios of the characteristic Cu(I)–CO bands at 2160 and 2146 cm−1 were observed which give information about the distribution of Cu(I) cations at different positions near the supercage. Lewis sites of different strengths are created by introduction of Cu resulting from Cu(I)/Cu(II) cations positioned in the super cages.