Interplay of Pt and Crystal Facets of TiO2: CO Oxidation Activity and Operando XAS/DRIFTS Studies

In this work, the influence of the terminating or exposed crystal planes of anatase TiO2 support on the catalytic activity of Pt/TiO2 catalysts is reported. Strong effects were observed when using CO oxidation as a probe reaction. The CO oxidation activity over these catalysts ranks in the following order: Pt/TiO2-{101} > Pt/TiO2-{100} > Pt/TiO2-{001}. The combination of in situ X-ray absorption spectroscopy, X-ray emission spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy, and density functional theory calculations unravelled a strong interaction between platinum particles and different dominating facets of anatase. The catalytic 0.2 activity of the Pt/TiO2 catalysts can be correlated with the spectroscopic/structural results. Compared to {001} facets, the {100} and 1100 facets of TiO2 can stabilize active highly dispersed Pt species and avoid sintering Pt particles. This finding provides some important insights into understanding the metal support interfacial interactions of Pt/TiO2 catalysts for tuning their catalytic performance.