Study on the mechanism of a manganese-based catalyst for catalytic NOX flue gas denitration

Abstract

Manganese-based bimetallic catalysts were prepared with self-made pyrolysis coke as carrier and its denitration performance of low-temperature SCR (selective catalyst reduction) was studied. The effects of different metal species, calcination temperature, calcination time and the metal load quantity on the denitration performance of the catalyst were studied by orthogonal test. The denitration mechanism of the catalyst was analyzed by XRD (X-ray diffraction), SEM (scanning electron microscope), BET test and transient test. The experiments show that: ① The denitration efficiency of Mn-based bimetallic catalysts mainly relates to the metal type, the metal load quantity and the catalyst adjuvant type. ② The optimal catalyst preparation conditions are as follows: the load quantity of monometallic MnO2 is 10%, calcined at 300°C for 4h, and then loaded with 8% CeO2, calcined at 350°Cfor 3h. ③ The denitration mechanism of manganese-based bimetallic oxide catalysts is stated as: NH3 is firstly adsorbed by B acid center Mn-OH which nears Mn4+==O to form NH4+, NH4+ was then attacked by the gas phase NO to form N2, H2O and Mn3+-OH. Finally, Mn3+-OH was oxidized by O2 to regenerate Mn4+.

Preparation of Quasi-MIL-101(Cr) Loaded Ceria Catalysts for the Selective Catalytic Reduction of NOx at Low Temperature

“…With the acceleration of urbanization and industrialization, people enjoy a convenient life while also suffering bad effects from various harmful pollutants. The emission control of nitrogen oxides (NO x ) resulting from fossil fuel combustion has been a major environmental concern related to air quality, as they cause a variety of environmentally harmful effects such as acid rain, photochemical smog, greenhouse effects, and ozone depletion [1][2][3]. At present, several methods have been used for the elimination of NO x , such as plasma catalysis [4,5], selective catalytic reduction (SCR) [6][7][8][9], and selective non-catalytic reduction (SNCR) [10,11].…”

“…Catalyst plays an important part in the NH 3 -SCR technology. The common commercialized industrial catalysts for this process are the mixture of V 2 O 5 with WO 3 and MoO 3 , supported by anatase TiO 2 [12][13][14], which shows high catalytic activity for NO The Brunauer-Emmett-Teller (BET), Scanning electron microscope (SEM), Transmission electron microscopy (TEM), Thermogravimetric (TG), X-ray photoelectron spectroscopy (XPS), and so on.…”

Research Status and Prospect on Vanadium-Based Catalysts for NH3-SCR Denitration

“…NH 4 + is then reacted with NO to create N 2 , H 2 O and Mn 3+ –OH. Finally, Mn 3+ is reoxidized to regenerate Mn 4+ [39]. The addition of Mn shows a promoting effect on the activity of the V 2 O 5 /TiO 2 catalyst because manganese oxides contain various valence states, facilitating the completing of the catalytic cycle.…”

Ultrasonication-Assisted Preparation of a Mn-Based Blast Furnace Slag Catalyst: Effects on the Low-Temperature Selective Catalytic Reduction Denitration Process

“…The denitration mechanism of the Mn-based SCR denitration catalyst is as follows: NH 3 is first adsorbed by the B acid center Mn–OH, which nears Mn 4+ O to form NH 4+ ; NH 4+ is then attacked by the gas-phase NO to form N 2 , H 2 O, and Mn 3+ –OH. Finally, Mn 3+ –OH was oxidized by O 2 to regenerate Mn 4+ …”

“…Finally, Mn 3+ −OH was oxidized by O 2 to regenerate Mn 4+ . 38 Blast furnace slag is produced by melting and quenching of iron ore and contains CaO, MgO, Al 2 O 3 , SiO 2 , and other substances. With the development of the steel industry, the output of blast furnace slag continues to increase.…”