Well-dispersed Pt on TiO2: A highly active and selective catalyst for hydrogenation of 3-nitroacetophenone

Pt nanoparticles with size between 2 and 7 nm supported on TiO2 were prepared by a deposition-precipitation method. These catalysts were characterized by nitrogen sorption, powder X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. The effects of Pt loading and reaction conditions on the hydrogenation properties of 3-nitroacetophenone over Pt/TiO2 were investigated. The results show that the catalytic performance of Pt/TiO2 for 3-nitroacetophenone hydrogenation to 3-aminoacetophenone is better than those of Rh/TiO2 and Rh/SiO2. The specific activity of Pt in the Pt/TiO2 for 3-nitroacetophenone hydrogenation increases nearly two times when the Pt loading in the Pt/TiO2 decreases from 1.5 wt% to 03 wt%. The selectivity to 3-aminoacetophenone can be up to 100% at complete conversion of 3-nitroacetophenone over the 0.3 wt% Pt/TiO2 even at high temperature and H-2 pressure. The high activity and excellent selectivity of the 0.3 wt% Pt/TiO2 are primarily derived from Pt nanopartides and TiO2 support as well as the interaction between them. The reaction conditions also have a pronounced effect on the catalytic performance. Higher reaction temperature, H-2 pressure and polar solvent are favorable for 3-nitroacetophenone hydrogenation to 3-aminoacetophenone over the 0.3 wt% Pt/TiO2. (C) 2015 Elsevier B.V. All rights reserved.