La and Co Addition to Mn/TiO₂ Catalysts for Enhancing Low-Temperature Denitrification Activity and H₂O/SO₂ Tolerance

Abstract

Manganese oxide-based denitrification catalysts supported by anatase with active components of Mn, Mn–La, Mn–Co, and Mn–La–Co oxides were prepared by a coprecipitation approach, and comparisons of their catalytic activities were made. The influences of Co and La addition on the NO removal and H2O/SO2 tolerance of the MnO x catalysts were investigated. The reasons for the different catalytic performances were investigated by using XRD, XPS, H2-TPR, and NH3-TPD experiments. The reaction mechanism of selective catalytic reduction of NO x with ammonia was determined by in situ diffuse reflectance infrared Fourier transform spectroscopy. Experiments proved that the addition of Co and La expanded the active temperature window (120–369 °C) and improved the sulfur tolerance due to the increase in the contents of Mn4+ and surface-active oxygen, along with the enhancement of the redox capacity of the catalyst. Different NH3–SCR reaction mechanisms were found over the catalysts Mn–La–Co/TiO2 and Mn/TiO2: the former was both the Eley–Rideal and Langmuir–Hinshelwood mechanisms, while the latter followed only the Langmuir–Hinshelwood mechanism. In addition, a “fast SCR” reaction mechanism was active for all catalysts. This work provides useful insights for improving the sulfur tolerance of manganese-based denitrification catalysts.

A Novel MnOx–MoOx Codoped Iron-Based Catalyst for NH3-SCR with Superior Catalytic Activity over a Wide Temperature Range

“…Figure d elucidates the forms of the oxygen species. The peaks at 529.7–530 eV correspond to lattice oxygen (O β ), the peaks at 531.4 eV pertained to surface adsorbed oxygen (O α ), and peaks ranging from 532.3 to 533.2 eV are attributed to the weak adsorption of H 2 O or −OH groups. , O α exhibits higher mobility than O β , which is favorable for the conversion of NO to NO 2 and contributes to improved SCR reaction rates. As detailed in Table , the MFMo 4 boasted a higher proportion of O α compared to the MF catalyst, which was in agreement with the test outcome that MFMo 4 was more active .…”

Acidified SiO2 Supported Fe-based Bimetal Oxide Catalyst with Resistance to High-Level Alkali Poisoning for CO Selective Catalytic Reduction of NO Removal of NOx

“…In addition to alkali metals, the practical flue gas of power plants inevitably contains a certain amount of SO 2 and H 2 O, which will compete with reactant gases for adsorption and weaken the activity of surface sites. Moreover, the regulation of the O 2 concentration is typically utilized to control combustion, resulting in frequent changes of the O 2 content of flue gas.…”