TiO2 nanotube-supported ruthenium(III) hydrated oxide: A highly active catalyst for selective oxidation of alcohols by oxygen

Ruthenium(III) hydrated oxide was deposited onto the surface of TiO2 nanotubes via ion exchange followed by alkali treatment. The catalytic activity of Ru(III)/TiO2 catalyst for the selective oxidation of alcohols by oxygen was studied in a continuous multichannel, compact reactor. It was found that the activity of Ru(III)/TiO2 (turnover frequency [TOF] ⩽ 450 h−1) is greater than that of a recently reported Ru(III)/Al2O3 catalyst (TOF = 335 h−1), and that the ruthenium loading could exceed 8 wt% without any significant loss of specific catalytic activity. High-resolution transmission electron microscopy and X-ray diffraction data show that ruthenium is highly dispersed on both the inner and the outer surfaces of the mesoporous TiO2 nanotubes with the diameter of nanoparticles between 1.2 and 2.4 nm, and is easily accessible by reactant molecules.