EXAFS study of Cu/C catalysts

A local arrangement of copper in Cu/C catalysts for dimethylcarbonate synthesis was studied by EXAFS. The samples with various Cu content were prepared by impregnating of carbon carrier “Sibunit” with the alcohol solution of CuCl2. It was determined, that the oxygen atoms from surface groups of carrier always enter into copper surrounding and the relative content of oxygen drops with the increase of Cu content in the samples. The structure of surface copper compounds for initial catalysts was proposed. Thus, samples with low Cu content (9×10−4 mol/g-cat) possess surface compounds [carrier-COO–CuCl] or [carrier–CO–CuCl], further, by increasing copper content a second surface layer consisting of hydrated CuCl2 non-bounded with carrier is formed.