biostudies-literatureUnknown7(10)Dong ALow-temperature selective catalytic oxidation (SCO) is crucial for removing the NH₃ slip from the upstream of NH₃-selective catalytic reduction (NH₃-SCR). Herein, combining zeolite Cu-SAPO34 and the active oxidant mullite SmMn₂O₅, we developed mixed-phase catalysts SmMn₂O₅/Cu-SAPO34 by grinding powder mixtures to achieve a low-temperature activity and a reasonable N₂ selectivity. The physicochemical properties of the catalysts were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) measurement, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The evaluation of NH₃ oxidation activity showed that for 30 wt % SmMn₂O₅/Cu-SAPO34, 90% NH₃ conversion was at a temperature of 215 °C in the presence of 500 ppm NH₃ and 21% O₂ balanced with N₂. The in situ DRIFTS spectra reveal the internal SCR mechanism (i-SCR), i.e., NH₃ oxidizing to NO <i>_x</i> on mullite and NO <i>_x</i> subsequently to proceed with SCR reactions, leading to higher conversion and selectivity over the mixed catalysts. This work provides a strategy to design the compound catalyst to achieve low-temperature NH₃ oxidation via synergistic utilization of the advantages of each individual catalyst.ACS omega8633-8639https://www.ebi.ac.uk/biostudies/studies/S-EPMC8928535biostudies-literatureMixed Catalyst SmMn₂O₅/Cu-SAPO34 for NH₃-Selective Catalytic Oxidation.PMC8928535Yang ZWang WDong AfalseMixed Catalyst SmMn₂O₅/Cu-SAPO34 for NH₃-Selective Catalytic Oxidation.Low-temperature selective catalytic oxidation (SCO) is crucial for removing the NH₃ slip from the upstream of NH₃-selective catalytic reduction (NH₃-SCR). Herein, combining zeolite Cu-SAPO34 and the active oxidant mullite SmMn₂O₅, we developed mixed-phase catalysts SmMn₂O₅/Cu-SAPO34 by grinding powder mixtures to achieve a low-temperature activity and a reasonable N₂ selectivity. The physicochemical properties of the catalysts were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) measurement, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The evaluation of NH₃ oxidation activity showed that for 30 wt % SmMn₂O₅/Cu-SAPO34, 90% NH₃ conversion was at a temperature of 215 °C in the presence of 500 ppm NH₃ and 21% O₂ balanced with N₂. The in situ DRIFTS spectra reveal the internal SCR mechanism (i-SCR), i.e., NH₃ oxidizing to NO <i>_x</i> on mullite and NO <i>_x</i> subsequently to proceed with SCR reactions, leading to higher conversion and selectivity over the mixed catalysts. This work provides a strategy to design the compound catalyst to achieve low-temperature NH₃ oxidation via synergistic utilization of the advantages of each individual catalyst.2022-01-01T00:00:00Z2022 Mar2025-04-04T20:22:15.653Z2025-04-04T20:22:15.653ZS-EPMC89285353530948910.1021/acsomega.1c06648