Oxidation of soot over supported RuRe nanoparticles prepared by the microwave-polyol method

Katarzyna Adamska,Agnieszka Hojeńska,Szymon Smykała,Sebastian Zieliński,Damian Szymański,Paweł Stelmachowski,Janina Okal,Andrzej Kotarba

doi:10.1007/s11144-021-02048-y

Abstract

The oxidation of soot over RuRe bimetallic nanoparticles (NPs) supported on γ-Al2O3 has been investigated. The catalysts were synthesized by a microwave-polyol method and characterized by ICP, BET, TEM, STEM-EDS, XRD and XPS techniques. The study revealed that the proper choice of the Re loading (0.4–2.0 wt%) is crucial for the catalytic behavior of the 2% Ru–Re/Al2O3 nano-catalysts.The best catalytic properties, in terms of overall activity and stability, were observed for the 2%Ru-0.8%Re/γ-Al2O3 nano-catalyst. The stability of all bimetallic 2% Ru–Re nano-catalysts in catalytic soot oxidation in the presence of oxygen is very high in contrast to the 2% Ru/γ-Al2O3 sample. The presence of rhenium in the catalytic system hinder the formation of large RuO2 agglomerates leading to a better dispersion of active ruthenium phase and a better catalytic performance. The relationship between the catalytic activity of Ru–Re/γ-Al2O3 and the synergetic roles of Ru and Re is discussed.

Highlights

Particle matters (PM) suspended in the air are responsible for the black smoke, which is one of the biggest problems of modern society
We reported that colloidal synthesis in ethylene glycol using a microwave reactor is an effective new method for obtaining RuRe bimetallic nanoparticles (NPs) with the diameters of a few nanometers [26]
In the first catalytic cycle the temperature of soot ignition for Ru nano-catalyst was found at 403 °C, while for Ru–Re nano-catalysts it was found to be in the range of 412- 445 °C

Summary

Introduction

Particle matters (PM) suspended in the air are responsible for the black smoke, which is one of the biggest problems of modern society. The gasoline direct injection engines can comply with the PM gravimetric Euro 6 limit, but solid particles emitted from them are very small (mostly below 100 nm) and particulate number (PN) emission significantly exceeds the acceptable threshold [1] For this reason, the newest EU regulations enforce the control of the particulate emission from gasoline engines. The diesel and gasoline particulate matters consist of carbonaceous soot and minor components of the volatile organic fraction (VOF) from unburned fuel, lubricating oil, and inorganic phases, for example, ash or sulfur combinations [3]. Several of these compounds are considered carcinogenic and mutagenic

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