Shape-controlled TiO2 nanoparticles and TiO2 P25 interacting with CO and H2O2 molecular probes: a synergic approach for surface structure recognition and physico-chemical understanding

Integrated studies of CO on truncated bipyramidal TiO2 anatase nanoparticles mainly exposing smooth (101) surfaces provide the missing link between TiO2 single crystals and commercial TiO2 nanopowders with complex morphology. The synergy among high resolution transmission electron microscopy, IR spectroscopy and modeling correlates adsorbed CO stretching frequency to anatase surface types, and reveals how disorder of the adsorbed CO layer affects CO/TiO2 IR bands. Comparison of the two TiO2 nanoparticle types highlights the role of low coordination Ti4+ sites selectively present on TiO2 P25 in the photocatalytic decomposition of H2 O2, an important Reactive Oxygen Species (ROS) formed in photocatalytic processes.