Adsorption of bi-isonicotinic acid on anatase TiO2(1Â 0Â 1) and (0Â 0Â 1) studied by photoemission and NEXAFS spectroscopy

The adsorption of bi-isonicotinic acid (2,2′-bipyridyl-4,4′-dicarboxylic acid) on the surface of anatase TiO2(1 0 1) and (0 0 1) single crystals has been investigated using XPS and NEXAFS. The searchlight effect of NEXAFS has been used to determine the adsorption geometry of BINA on these surfaces. The pyridyl rings in BINA are found to be oriented at 20° ± 3° from the surface normal on the (1 0 1) surface and at 53° ± 5° from the surface normal on the reconstructed (0 0 1) surface.