Propane-1,3-diol Adsorption and Dissociation on Rutile TiO$_{2}$(110): A Scanning Tunneling Microscopy Study

Titanium Dioxide (TiO$_{2})$ has attracted great attention in the past decades due to its importance in heterogeneous catalysis. Here the adsorption and dissociation of Propane-1,3-diol molecules on partially reduced rutile TiO$_{2}$(110) surfaces are studied via variable temperature scanning tunneling microscopy (VT-STM). STM images of TiO$_{2}$(110) surfaces obtained before and after \textit{in-situ} doses of melecules at room temperature show that the molecules preferentially bind in bridge-bonded oxygen vancanies (BBO$_{V}$'s) \textit{via} one O-H bond scission. The dynamics of Propane-1,3-diol molecules motion has been investigated at room and elevated temperatures. Propane-1,3-diol molecules swing on TiO$_{2}$ surface with one end (-CH$_{2}$-O$^{-})$ anchored on vacancies. Strong interaction of the other end (-O-H) with Ti$_{5c}$ reduces the swing rate when compared with octanol.