# Synthesis, structure and three way catalytic activity of $Ce_{1-x}Pt_{x/2}Rh_{x/2}O_{2-\delta}$ (x = 0.01 and 0.02) nano-crystallites: Synergistic effect in bimetal ionic catalysts

Gayen, Arup and Baidya, Tinku and Biswas, Krishanu and Roy, Sounak and Hegde, MS (2006) Synthesis, structure and three way catalytic activity of $Ce_{1-x}Pt_{x/2}Rh_{x/2}O_{2-\delta}$ (x = 0.01 and 0.02) nano-crystallites: Synergistic effect in bimetal ionic catalysts. In: Applied Catalysis A: General, 315 . pp. 135-146.

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## Abstract

Bimetal ionic $Ce_{1-x}Pt_{x/2}Rh_{x/2}O_{2-\delta}$ (x = 0.01 and 0.02) catalysts have been synthesized by a single step solution combustion method. CO and $C_2H_4$ oxidation and NO reduction activities of the bimetal ionic catalysts are compared with mono-metal ionic $Ce_{1-x}Pt_xO_{2-\delta}$ (x = 0.01 and 0.02) and $Ce_{1-x}Rh_xO_{2-\delta}$ (x = 0.01 and 0.02) catalysts. X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) studies show incorporation of $Pt^{2+}$ and $Rh^{3+}$ ions in $CeO_2$ lattice. Low temperature hydrogen uptake at $0^oC$ and below over bimetal ionic catalyst shows enhanced redox property over the corresponding mono-metal ionic analogues. The TOF for CO oxidation over $Ce_{0.99}Pt_{0.005}Rh_{0.005}O_{2-\delta}$ is $0.035 s^{-1}$ at $120^oC$, compared to $0.003 s^{-1}$ over $Ce_{0.99}Pt_{0.01}O_{2-\delta}$ and $0.035 s^{-1}$ over $Ce_{0.99}Rh_{0.01}O_{2-\delta}$ at $135^oC$. Enhanced catalytic activity of $Ce_{1-x}Pt_{x/2}Rh_{x/2}O_{2-\delta}$ (x = 0.01) bimetal ionic catalysts compared to mono-metal ionic catalysts, $Ce_{1-x}Pt_xO_{2-\delta}$ and $Ce_{1-x}Rh_xO_{2-\delta}$, is attributed to synergism brought about by the easy reduction of $Rh^{3+}$ ion by $Pt^{2+}$ ion.

Item Type: Journal Article Copyroght of this article belongs to Elsevier. Pt–Rh synergism;Bimetal ionic catalysts;Ceria;Ionic dispersion. Division of Chemical Sciences > Solid State & Structural Chemistry UnitDivision of Mechanical Sciences > Materials Engineering (formerly Metallurgy) 08 Aug 2008 19 Sep 2010 04:48 http://eprints.iisc.ernet.in/id/eprint/15495