CO Adsorption on Anatase Nanocrystals: A Combined Experimental and Periodic DFT Study

Periodic DFT calculations of the structure of (101), (100), (001), and (112) anatase faces and of the vibrational properties of CO adsorbed on them at two coverages allow assigning the main features of FTIR spectra of CO adsorbed at 60 K on highly dehydroxylated anatase nanocyrstals. It is shown that the combination of spectroscopic and computational approaches is of extreme utility for the elucidation of the Lewis acid properties of the 5-fold coordinated Ti4+ centers present on the different surfaces and on their influence on the stretching frequencies of adsorbed CO, for the explanation of the coverage-dependent effect of dipole-dipole interactions and for the determination of the average nanoparticle morphology. This study highlights that the close comparison of experimental and computational results forms the safest basis for the cross-validation of the two approaches.