Enhanced selective catalytic reduction of NO with CO over Cu/C nanoparticles synthetized from a Cu-benzene-1,3,5-tricarboxylate metal organic framework by a continuous spray drying process

Abstract Cu-benzene-1,3,5-tricarboxylate (BTC), Cu-BTC (FNP), and Cu-BTC (SD) precursors were prepared by direct mixing (DM), flash nanoprecipitation (FNP) and spray drying (SD), respectively. The precursors were pyrolyzed under nitrogen to obtain the corresponding Cu/C-DM, Cu/C-FNP, and Cu/C-SD catalysts. The physicochemical and catalytic properties of these samples were characterized by scanning electron microscopy (SEM), N2 adsorption-desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, electronic paramagnetic resonance (EPR), temperature-programmed reduction with hydrogen (H2-TPR), temperature-programmed desorption of oxygen (O2-TPD), and CO + NO model reactions. Regarding the CO + NO model reactions, the Cu/C-SD catalyst exhibited the best denitrification performance, reaching complete NO conversion and N2 selectivity of 98.8% at 300 °C. The Cu/C-SD catalyst removed 88.1% of the initial NO at temperatures as low as 200 °C, being this value was significantly higher than those obtained by Cu/C-DM (2.6%) and Cu/C-FNP (10.2%) catalysts. The Cu/C-SD catalyst also showed excellent stability in the independent presence of O2 (5 vol%), H2O (5 vol%) or SO2 (100 ppm). The Cu1+/Cu0 ratio played a key role in the selective NO catalytic reduction process. The larger specific surface area of the Cu/C-SD catalyst and its ability for the reduction and desorption of oxygen chemically adsorbed has a positive impact on the catalytic performance of this material. These results were theoretically supported by a DFT analysis.