Microwave Plasma Treatment for Catalyst Preparation: Application to Alumina Supported Silver Catalysts for SCR NO&amp;lt;sub&amp;gt;x&amp;lt;/sub&amp;gt; by Ethanol

Marjorie Foix,Michael Tatoulian,Patrick Da Costa,Cédric Guyon

doi:10.4236/mrc.2013.23011

Abstract

Thermal treatment either in the presence of oxygen (calcination) or of a reducing agent (reduction) result is all the time a key issue within the preparation of a catalyst. In this work, a microwave plasma treatment was chosen as an alternative to typical calcinations, because it is a more energy efficient process. Thus, a Microwave Fluidized Bed Plasma reactor (MFBP) was employed in catalyst synthesis process under different gas compositions, such as argon and argon/oxygen mixtures over g-alumina supported silver catalysts, which are generally used for selective reduction of NOx by ethanol. After the first catalytic tests performed in the presence of plasma treated catalyst, it can be concluded that plasma treatment process represents an interesting alternative to conventional calcination during catalyst synthesis, resulting in a more sustainable process, moreover in view of its industrial application. In order to understand the particular effect of plasma treatment, the catalysts submitted to this treatment were carefully characterized by means of thermo gravimetric analysis (TGA), differential thermal analysis (DTA) and UV-VIS-NIR.

Highlights

All around the world, the major chemical engineering processes are catalytic processes
A Microwave Fluidized Bed Plasma reactor (MFBP) was employed in catalyst synthesis process under different gas compositions, such as argon and argon/oxygen mixtures over -alumina supported silver catalysts, which are generally used for selective reduction of NOx by ethanol
In order to understand the particular effect of plasma treatment, the catalysts submitted to this treatment were carefully characterized by means of thermo gravimetric analysis (TGA), differential thermal analysis (DTA) and UV-VIS-NIR

Summary

Introduction

The major chemical engineering processes are catalytic processes. Most the used catalysts are heterogeneous supported catalysts. An effective catalyst is generally described to have a high specific surface area in which the catalytic phase ishighly dispersed. In commercial form, the final catalyst should possess high mechanical strength and resistance to high temperatures [1]. Conventional synthesis of supported catalysts comprises four main steps, namely: 1) impregnation of the active phase; 2) maturation; 3) drying; 4) thermal activation such as calcination or reduction. The lack of an accurate control of some of these operations results in catalytic preparation procedures, which may be far from perfect [2,3]

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Conclusion