Speciation of CuO in MCM-41 during oxidation of naphthalene

By extended X-ray absorption fine structural (EXAFS) spectroscopy, copper oxide clusters with a square-plane structure are found in the channels of mesoporous molecular sieve MCM-41. Bond distances of Cu-O and Cu-Cu are 1.90 and 2.80 Å, respectively. Oxidation of naphthalene at 723 K for 4 h in MCM-41 leads to structural perturbation of the clusters (e.g., Cu-O: −0.02 Å and Cu-Cu: +0.02 Å) with little change in their coordination numbers.