Copper Supported on Mesoporous Structured Catalysts for NO Reduction

Mariana B S Felgueiras,Manuel F R Pereira,João Restivo,Olívia S G P Soares,Juliana P S Sousa

doi:10.3390/catal12020170

Mariana B S Felgueiras, Manuel F R Pereira + Show 3 more

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https://doi.org/10.3390/catal12020170

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Abstract

Nitrogen oxides (NOx) are one of the pollutants of greatest concern in terms of atmospheric contamination and, consequently, human health. The main objective of this work, is the synthesis of structured carbon catalysts, introducing on their surface metals and nitrogen groups, catalytically active in NO reduction. Structured catalysts represent an attractive alternative to powder catalysts because they have better thermal stability and lower pressure drop. The catalysts were synthesized by coating a melamine foam using precursor solutions of carbon xerogels with and without nitrogen (using melamine and urea as precursors), and impregnated with transition metals (Fe, Ni and Cu). The introduction of nitrogen and metals modified the textural properties of the materials. Samples synthesized with melamine presented the highest amount of nitrogen, while the highest content of copper, found to be the most active transition metal for NO reduction, was found in structured catalysts impregnated with urea. The presence of transition metals in catalysts is essential for the reduction of NO to N2 and the introduction of nitrogenous precursors makes this evident. The synthesis and application of carbon-supported structured catalysts containing transition metals for NO reduction is demonstrated in this work for the first time, as well as the study of the factors influencing their performance.

Highlights

Pollution is one of the problems with significant impact in the 21st century caused by excessive human consumption, directly affecting the climate, the quality of drinking water, agricultural production and, the health of living beings
The main objective of this work was the synthesis and characterization of structured carbon catalysts, introducing metals and nitrogen groups, catalytically active in the reduction of Nitrogen monoxide (NO) to contribute to the reduction of its emissions
In the NO reduction tests performed with carbon xerogel (CX), the presence of transition metals in the structure was essential for catalytic activity and the introduction of nitrogenous groups in the CX structure, using melamine as a precursor, enhanced the catalytic results

Summary

Introduction

Pollution is one of the problems with significant impact in the 21st century caused by excessive human consumption, directly affecting the climate, the quality of drinking water, agricultural production and, the health of living beings. Several measures have been applied to reduce their emissions, essentially in the chemical and transport industries, to prevent these gases from being emitted into the atmosphere. The methods used to reduce NOx emission are divided into two main groups: primary and secondary methods. The former reduce NOx emissions by up to 50% and are preventive measures that consist of changing operating conditions and organizing the process during pre-combustion and combustion [3]. The latter are applied after combustion and reduce up to 100% of the nitrogen oxides already formed [2]

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