XPS characterization of?-zirconium phosphate and of some of its intercalation compounds. A comparison with the ?-zirconium phosphate analogues

An X-ray photoelectron spectroscopic investigation ofγ-Zr (HP04)2·2 H2O and its intercalation compounds with 1,10-phenanthroline, Co2+-phenanthroline and Cu2+-phenanthroline is described. The analysis of theNls spectra of the compound containing only phenanthroline clearly shows that, on average, more than one nitrogen atom of the diamine interacts with the acid groups of the host, giving protonated species. XPS also provides evidence of the coordination of Co2+ and Cu2+ ions after their diffusion in the phenanthroline-γ-zirconium phosphate intercalation compound. They form mixed N-and O-coordinated species with the diamine and the oxygens of the interlayer region, but the presence of the characteristic peaks of uncoordinated phenanthroline, even at low intensity, shows that the diamine molecules anchored to the host are still present.