Article: Effect of surface treatments on Li0.30Ln0.57TiO3 (Ln = La, Nd) perovskite ceramics: an X-ray photoelectron spectroscopy study
 

[B]Effect of surface treatments on Li0.30Ln0.57TiO3 (Ln = La, Nd) perovskite ceramics: an X-ray photoelectron spectroscopy study[/B]

Surface Science, Volume 572, Issues 2-3, 20 November 2004, Pages 375-384

Quoc Nghi Pham, Claude Bohnke, Odile Bohnke

[B]Abstract[/B]

To explain the sensitivity of some titanate ceramics to pH variation in aqueous solutions, the lithium lanthanum titanate (LLTO) and lithium neodymium titanate (NLTO) surfaces were analysed by X-ray photoelectron spectroscopy. The surface of LLTO was modified by chemical treatments and sputtering. XPS spectrum of LLTO exhibits the peaks of lanthanum (La 3d3/2, La 3d5/2, La 4p, La 4d), titanium (Ti 2p1/2, Ti 2p3/2) and oxygen (O 1s). However, the immersion of the ceramic in sodium hydroxide or surface sputtering affect mainly the narrow-scan spectra of oxygen (O 1s). This study reveals that an acido-basic reaction takes place in the neighbourhood of the TiO6 octahedra of the perovskite. The results also suggest that hydroxyl species may associate with lanthanum. Furthermore, the study on C 1s line rules out the assumption that View the MathML source species are involved in the pH detection.

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