Computational Screening and Experimental Synthesis of Doped TiO2 for Propane Dehydrogenation

Abstract

Low-cost, environmentally friendly, and highly efficient catalysts are urgently needed for the direct propane dehydrogenation (PDH) to propylene. Studies have shown that defective TiO2 obtained by in situ reduction shows excellent catalytic PDH performance. Doping metals in the lattice of TiO2 is a plausible method for tuning the vacancy content and electronic property. In this paper, doping with fifth period transition metals was screened using a computational method, followed by experimental synthesis to further improve the PDH activity of TiO2-based catalysts. The TiO2 (101) surface with doping metals was first studied to determine the positive effect on the vacancy formation. Then, the two disputed reaction paths, that is, the concerted and stepwise path, were compared extensively on all of the doping models. Step one is found to be more preferable for all. The microkinetic modeling was employed to obtain the turnover frequency (TOF), based on which the linear relationship is found for TOF and binding energy of dissociated H2 or co-adsorption energy of 2-propyl&H. The abovementioned screening process shows Ru-doped TiO2, which shows the highest PDH activity and is justified by experimental results.