Catalytic activity of Cu/η-Al2O3 catalysts prepared from aluminum scraps in the NH3-SCO and in the NH3-SCR of NO.

Nawel Jraba,Gerard Delahay,Thabet Makhlouf,Hassib Tounsi

doi:10.1007/s11356-021-16206-1

Nawel Jraba, Gerard Delahay + Show 2 more

Open Access

https://doi.org/10.1007/s11356-021-16206-1

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Abstract

Copper-loaded η-alumina catalysts with different copper contents were prepared by impregnation/evaporation method. The catalysts were characterized by XRD, FTIR, BET, UV-Vis, and H2-TPR and evaluated, for the first time, in the selective catalytic reduction of NO by NH3 and in the selective catalytic oxidation of NH3. The characterization techniques showed that the impregnation/evaporation method permits to obtain highly dispersed copper oxide species on the η-alumina surface when a low amount of copper is used (1wt. % and 2 wt.%). The wet impregnation method made it possible to reach a well dispersion of the copper species on the surface of the alumina for the low copper contents Cu(1)-Al2O3 and Cu(2)-Al2O3. The latter justifies the similar behavior of Cu(1)-Al2O3) and Cu(2)-Al2O3 in the selective catalytic oxidation of NH3 where these catalysts exhibit a conversion of NH3 to N2 of the order of 100% at T> 500 °C.

Highlights

The selective catalytic reduction (SCR) of NO) − ( (NO) by ammonia in the presence of excess oxygen is considered a mature technology for the removal of NO from stationary sources (Forzatti, 2001; Usberti et al 2015)
This system contains besides the urea delivery device, a catalyst for the selective catalytic reduction of NO with NH3 (NH3-SCR) combined with an ammonia slip catalyst (ASC) for the selective catalytic oxidation of ammonia (NH3-SCO) (Piumetti et al, 2015; Walker, 2016)
Cu[1]-Al2O3 and Cu[2]-Al2O3 catalysts, there is a slight decrease in the intensity of the peaks of the support and the peak at 19.5 ° and the absence of the diffraction peaks of CuO

Summary

Introduction

The selective catalytic reduction (SCR) of NO by ammonia in the presence of excess oxygen is considered a mature technology for the removal of NO from stationary sources (Forzatti, 2001; Usberti et al 2015). 1999 studied supported CuO/γ-Al2O3 catalysts containing 5, 10 and 15 wt.% of copper They found that the best catalytic results in the NH3-SCO were obtained for the sample loaded with 10 wt.% of Cu (90% of NH3 conversion with 97% selectivity to N2 at 300°C). Osman et al, (2017) showed that loading η-Al2O3 with 10 wt.% of silver enhanced both surface Lewis acidity and the hydrophobicity of the carrier They obtained a catalyst with high degree of activity and stability under steady-state conditions for the production of DME. CuO/ η-Al2O3 catalysts were prepared by impregnation/evaporation method using copper acetate as precursor These catalysts were tested for the first time in the reactions of NH3-SCR of NO and of NH3-SCO in presence of water vapour. The prepared CuO/ η-Al2O3 catalysts were characterized by XRD, SEM, TEM, NH3-TPD, H2-TPR, UV-vis and N2 adsorption-desorption techniques

Preparation of the catalysts

Characterization of the catalysts

Selective Catalytic Reduction of NO by NH3

Conclusion