Microwave Plasma Treatment for Catalyst Preparation: Application to Alumina Supported Silver Catalysts for SCR NO<sub>x</sub> by Ethanol

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 -alumina supported silver catalysts, which are generally used for selective reduction of NO x 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.

Catalytic Plasma Fischer–Tropsch Synthesis Using Hierarchically Connected Porous Co/SiO2 Catalysts Prepared by Microwave-Induced Co-assembly

“…The coassembled supported catalysts used in this study have very high heterogeneity especially at high catalyst/silica ratio when they generate plasma during synthesis under microwave radiation . The same effect occurs when the catalyst is exposed to plasma in plasma reactors, albeit at a much reduced rate. , …”

“…1 The same effect occurs when the catalyst is exposed to plasma in plasma reactors, albeit at a much reduced rate. 3,81 We can attribute the enhancement of CO conversion after reaching a minimum to the fact that prolonged exposure of the Catalyst-ABC-400 results in morphological changes which in turn increases the heterogeneity and the activity of the catalyst. It is also noteworthy that the Catalysts-ABC-400-D and ABC-Table 3.…”

Plasma DBD activated ceria-zirconia-promoted Ni-catalysts for plasma catalytic CO2 hydrogenation at low temperature

“…Plasma technologies can also be used for catalytic synthesis [10][11][12][13][14][15]. In general, there are three main trends in catalyst preparation using plasma technologies: plasma chemical synthesis of ultrafine particle catalysts [11,12], plasma assisted deposition of catalytically active compounds on various supports [13][14][15] and plasma enhanced preparation or plasma modification of catalysts [12,16,17]. A recent work evidenced that radio frequency or microwave plasma treated catalysts led to higher catalytic efficiency in NO x abatement for hydrocarbon SCR (Selective Catalytic Reduction) in comparison to classical calcined catalysts [15,18].…”

Preparation of a Pd/Al2O3 Catalyst with Microwave-Induced Plasma Jet Irradiation under Atmospheric Pressure

“…Plasma, considered as the fourth state of matter, is a partially ionized gas that contains excited species as radicals. Plasma has been introduced into various catalyst preparation processes as an alternative to conventional thermal treatment [1][2][3][4][5][6][7]. Various types of plasma, including dielectric barrier discharge, radio frequency, and microwave-induced plasma, have been applied in catalyst modification, and remarkable advantages have been observed.…”

“…Microwave plasma has been applied for Ag/Al 2 O 3 catalyst preparation under vacuum conditions. With this intervention, higher nitric oxide (NOx) reduction efficiency in the selective catalytic reduction with ethanol was observed when compared to that of calcined catalysts [5]. Plasma treatment for catalysts could enhance metal and support interactions [6,7].…”