Highly oxidized Pt species stabilized inside carbon nanotubes for asymmetric hydrogenation

The chemical state and its influence on Pt species in or outside of the channels of CNTs and the effect on the asymmetric hydrogenation of alpha-ketoester ikere investigated. XPS analysis showed that 13% Pt species in a highly oxidized state (Pt4+) were stabilized inside the channels in the presence of Na+. There were more highly oxidized Pt species inside the CNTs than outside. The highly oxidized Pt species promoted the interaction between the nanoparticle and chiral modifier, which is crucial for high enantioselectivity. Hydrogen temperature programmed desorption showed that Pt nanoparticles confined in the channels can better activate hydrogen, which contributed to their high activity even at low hydrogen pressure. (C) 2015, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved