Enhanced reducibility of Ce1-xTixO2 compared to that of CeO2 and higher redox catalytic activity of Ce1-x-yTixPtyO2-δ compared to that of Ce1-xPtxO2-δ

Baidya, Tinku ; Gayen, Arup ; Hegde, M. S. ; Ravishankar, N. ; Dupont, Loic (2006) Enhanced reducibility of Ce1-xTixO2 compared to that of CeO2 and higher redox catalytic activity of Ce1-x-yTixPtyO2-δ compared to that of Ce1-xPtxO2-δ Journal of Physical Chemistry B, 110 (11). pp. 5262-5272. ISSN 1089-5647

Full text not available from this repository.

Official URL: http://pubs.acs.org/doi/abs/10.1021/jp0565103

Related URL: http://dx.doi.org/10.1021/jp0565103

Abstract

Nanocrystalline Ce1-xTixO2 (0 = x = 0.4) and Ce1-x-yTixPtyO2-δ (x = 0.15, y = 0.01, 0.02) solid solutions crystallizing in fluorite structure have been prepared by a single step solution combustion method. Temperature programmed reduction and XPS study of Ce1-xTixO2 (x = 0.0-04) show complete reduction of Ti4+ to Ti3+ and reduction of 20% Ce4+ to Ce3+ state compared to 8% Ce4+ to Ce3+ in the case of pure CeO2 below 675 °C. The substitution of Ti ions in CeO2 enhances the reducibility of CeO2. Ce0.84Ti0.15Pt0.01O2-δ crystallizes in fluorite structure and Pt is ionically substituted with 2+ and 4+ oxidation states. The H/Pt atomic ratio at 30 °C over Ce0.84Ti0.15Pt0.01O2-δ is 5 and that over Ce0.99Pt0.01O2-δ is 4 against just 0.078 for 8 nm Pt metal particles. Carbon monoxide and hydrocarbon oxidation activity are much higher over Ce1-x-yTixPtyO2 (x = 0.15, y = 0.01, 0.02) compared to Ce1-xPtxO2 (x = 0.01, 0.02). Synergistic involvement of Pt2+/Pt° and Ti4+/Ti3+ redox couples in addition to Ce4+/Ce3+ due to the overlap of Pt(5d), Ti(3d), and Ce(4f) bands near EF is shown to be responsible for improved redox property and higher catalytic activity.

Item Type:Article
Source:Copyright of this article belongs to American Chemical Society.
ID Code:16252
Deposited On:15 Nov 2010 13:58
Last Modified:03 Jun 2011 07:31

Repository Staff Only: item control page