Effects of MnO2 Crystal Phases in MnO2/CeO2 Catalyst for NO Reduction by NH3-SCR

The low-temperature (α-/β-/γ-/δ-MnO 2 /CeO 2 -Nanorod) catalysts have been synthesized using the hydrothermal method followed by wet-impregnation and anaylzed in the Inconel reactor for selective catalytic reduction of NO using NH 3 as a reducing agent. The catalysts were characterized by the Brunauer-Emmett characterized catalysts–Teller, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy-Energy dispersive X-ray spectroscopy, transmission electron microscopy and Raman spectroscopy. The characterization analysis of the catalysts revealed that the α-MnO 2 /CeO 2 -Nanorod has the highest specific surface area, surface Ce 3+ and Mn 4+ , and oxygen storage capacity among all the catalysts. The activity results exhibited that in the 50–450 °C temperature range, the α-MnO 2 /CeO 2 -Nanorod has the maximum NO conversion and N 2 selectivity. It showed the highest NO conversion (75%) and N 2 selectivity (86%) at 250 °C. As the amount of α-MnO 2 increased in the α-MnO 2 /CeO 2 -Nanorod catalyst, the NO conversion with N 2 selectivity exceeded 94.25% and 95%, respectively. Graphical Abstract