Samples were prepared as KBr pellets. X-ray powder diffraction (XRD) data were collected on a Rigaku XRD-6000 and a Pananalytical X'pert PRO diffractometers using Cu Kα radiation (λ = 0.154 nm). X-ray photoelectron spectroscopy (XPS) measurements were performed from the samples deposited on a gold support using a UHV Multiprobe system (Scienta Omicron, Germany) with a monochromatic X-ray source (Al K) and an electron analyzer (Argus CU) with 0.6 eV energy resolution.