PNNL

Abstract

The adsorption and reaction of acetaldehyde (CH3CHO), on stoichiometric (TiO2-terminated) and reduced SrTiO3(100) surfaces, have been investigated using temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS). Acetaldehyde adsorbs molecularly on the stoichiometric SrTiO3(100) surface that contains predominately Ti4? cations. The Ti4? sites on the stoichiometric SrTiO3(100) surface are not sufficiently active for surface reactions such as aldol condensation, as opposed to the Ti4? ions on the TiO2 (001) surface. However, decomposition and redox reactions of acetaldehyde occur in the presence of surface defects created by Ar? sputtering. The decomposition products following reactions of acetaldehyde on the defective surface include H2, C2H4, CO, C4H6 and C4H8. Reductive coupling, to produce C2H4 and C4H8, is the main reaction pathway for decomposition of acetaldehyde on the sputter reduced SrTiO3 (100) surface.