# Single step direct coating of 3-way catalysts on cordierite monolith by solution combustion method: High catalytic activity of $Ce_{0.98}Pd_0.02O_{2-\delta}$

Sharma, Sudhanshu and Hegde, MS (2006) Single step direct coating of 3-way catalysts on cordierite monolith by solution combustion method: High catalytic activity of $Ce_{0.98}Pd_0.02O_{2-\delta}$. In: Catalysis Letters, 112 (1-2). pp. 69-75.

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## Abstract

A new process of coating of active exhaust catalyst over $\gamma-Al_2O_3$ coated cordierite honeycomb is reported here. The process consists of (a) growing $\gamma-Al_2O_3$ on cordierite by solution combustion of $Al(NO_3)_3$ and oxylyldihydrazide (ODH) at $600^oC$ and active catalyst phase $Ce_{0.98}Pd_{0.02}O_2-\delta$ on $\gamma-Al_2O_3$ coated cordierite again by combustion of ceric ammonium nitrate and ODH with $1.2\times 10^{-3} M PdCl_2$ solution at $500^oC$. Weight of active catalyst can be varied from 0.02 to 2 wt% which is sufficient but can be loaded even up to 12 wt% by repeating dip dry combustion. Adhesion of catalyst to cordierite surface is via oxide growth which is very strong. About 100% conversion of CO is achieved below $80^oC$ at a space velocity of 880$h^-1$. At much higher space velocity of 21,000 $h^-1$, 100% conversion is obtained below $245^oC$. Activation energy for CO oxidation is 8.4 kcal/mol. At a space velocity of 880 $h^-1$ 100% NO conversion is attained below $185^oC$ and 100% conversion of 'HC' $(C_2H_2)$ below $220^oC$. At same space velocity 3-way catalytic performance over $Ce_{0.98}Pd_{0.02}O_{2-\delta}$ coated monolith shows 100% conversion of all the pollutants below $220^oC$ with 15% of excess oxygen. In this method, handling of nano material – powder is avoided.

Item Type: Journal Article Copyright of this article belongs to Springer. Monolith;Cordierite;Honeycomb;Active phase;3-way catalyst Division of Chemical Sciences > Solid State & Structural Chemistry Unit 19 Feb 2007 19 Sep 2010 04:34 http://eprints.iisc.ernet.in/id/eprint/9395