XPS study on microporous titanosilicate ETS-10 upon acid treatment

In this work, we studied the structural change of microporous titanosilicate ETS-10 upon post-treatment with nitric acid using X-ray photoelectron spectroscopy (XPS) technique. The experimental results demonstrated that significant leaching of Ti species from the surface of ETS-10 occurred upon acid washing; in the meantime the equilibrium pH of the acidification solution was lowered. Analysis of the Ti 2p and O 1s XPS spectra of the acid-treated ETS-10 samples revealed the formation of tetrahedral Ti species due to Ti leaching from the -O-Ti-O-Ti-O- chains of ETS-10 framework, suggesting that the -O-Ti-O-Ti-O- chains are very sensitive to an acidic environment. (c) 2006 Elsevier Inc. All rights reserved.