CETMIC   05378
CENTRO DE TECNOLOGIA DE RECURSOS MINERALES Y CERAMICA
Unidad Ejecutora - UE
artículos
Título:
XPS Studies on the Cu(II)-polyampholyte heterogeneous catalyst and insight into its structure and mechanism
Autor/es:
J. LAZARO MARTINEZ; E. RODRIGUEZ CASTELLON; R. M. TORRES SÁNCHEZ; G. BULDAIN; V. CAMPO DALL´ORTO
Revista:
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Zurich; Año: 2011 vol. 339 p. 43 - 51
ISSN:
1381-1169
Resumen:
A complex between Cu(II) and a polyampholyte synthesized from methacrylic acid, imidazoleand ethyleneglycol diglycidyl ether was used as a heterogeneous catalyst for hydrogen peroxideactivation and degradation of chlorophenols. The material was characterized by XPS and bymeasurements of the zeta potential. The isoelectric point determined experimentally was 8.0, differing from that obtained by titration (6.4), which indicated the presence of fixed positive charges in disubstituted imidazole units. The XPS N 1s signal for pyridinic nitrogen in the imidazole units, and the O 1s signals from the carbonyl, hydroxyl and carboxylate groups shifted to higher binding energies after copper uptake, proving the chemical nature of Cu(II) adsorption on the polyampholyte. The XPS spectrum of the complex showed a Cu 2p3/2 peak at 934.7 eV and the characteristic shake-up satellite of Cu(II). When the complex was used as a heterogeneous catalyst for H2O2 activation, Cu(I) was proved to be a probable intermediate species and contributed to elucidate the mechanism. The complex was applied in the oxidation of chlorinated phenols in aqueous solution at room temperature without any loss in efficiency.