CuxO - TiO2 composites (x=1, 2) studied by X-ray Photoelectron Spectroscopy

CuxO - TiO2 (x=1, 2) nanocomposites were synthesized by an innovative Chemical Vapor Deposition (CVD) strategy, based on the initial growth of CuxO matrices (1) and on the subsequent dispersion of TiO2 nanoparticles (2). Cu(hfa)2*TMEDA (hfa=1,1,1,5,5,5-hexafluoro- 2,4-pentanedionate; TMEDA=N,N,N’,N’-tetramethylethylenediamine) and Ti(O-iPr)2(dpm)2 (O-iPr= isopropoxide; dpm=2,2,6,6-tetramethyl-3,5-heptanedionate) were used as copper and titanium molecular sources, respectively. The syntheses were carried out under O2+H2O atmospheres on Si(100) substrates. In step (1), pure and homogeneous single-phase Cu2O/CuO nanosystems were obtained at 400/550 °C, with total pressures of 3.0/10.0 mbar, respectively. Interestingly, the obtained nanocomposites were characterized by the surface formation of Cu(I)-Cu(II) mixtures, due to the occurrence of interactions between CuxO and TiO2. This work is dedicated to the characterization of two representative samples by X-ray Photoelectron Spectroscopy (XPS), focusing in particular on the analysis on the O 1s, Cu 2p and Ti 2p core levels.