Effects of Ni modification on NO‐CO reaction with MnO_x‐CuO/TiO₂ catalysts

Abstract

Ni modified MnOx‐CuO/TiO2 catalysts were synthesized by the sol‐gel method and investigated for NO‐CO reaction. The results showed that 0.05Ni‐Mn‐Cu/TiO2 (the Ni/Ti molar ratio was 0.05) had the highest NO conversion efficiency with a maximum value of 85.4 % at 350 °C, which was 10 % higher than that of Mn‐Cu/TiO2. XPS analysis showed that more chemisorbed oxygen formed on the Ni‐modified catalyst surface, which could act as active sites for CO adsorption and oxidation. CO‐TPD results confirmed that the amount of adsorbed CO on the catalyst surface increased after Ni modification. H2‐TPR results suggested that the Ni‐modified catalyst had better redox properties, which favoured the reduction of NO to N2O and N2O to N2. Furthermore, in situ FTIR showed that CO2 from the production of the NO‐CO reaction could be easily formed on the surface of 0.05Ni‐Mn‐Cu/TiO2, and it indicated that the NO‐CO reaction could easily occur after Ni doping. All these factors were responsible for the better catalytic activity of Ni‐modified catalysts.

Predictive control of SCR denitrification system in thermal power plants based on GA‐BP and PSO

“…Oxygen in the gas phase is transferred inside the catalyst to renew the surface oxygen, thus completing the catalytic cycle. [26][27][28] The kinetics of SCR denitrification can be divided into three processes: the adsorption process, the catalytic reduction process, and the desorption process. According to the gas-solid surface catalytic reaction mechanism, the reaction kinetics equations are as follows:…”

“…Oxygen in the gas phase is transferred inside the catalyst to renew the surface oxygen, thus completing the catalytic cycle. [ 26–28 ] The kinetics of SCR denitrification can be divided into three processes: the adsorption process, the catalytic reduction process, and the desorption process. According to the gas–solid surface catalytic reaction mechanism, the reaction kinetics equations are as follows: where is the coverage of adsorbed NH 3 on the catalyst, r a is the adsorption rate, r d is the desorption rate, r NO is the denitration reaction rate, r ox is the oxidation rate of adsorbed NH 3 , is the adsorption capacity of the catalyst for NH 3 , and C is the concentration of each gas in the gas phase.…”

Removing NOx, CO and HC from automobile exhaust based on chemical looping combustion

“…Zhang et al . synthesized a MnO x ‐CuO/TiO 2 catalyst modified with Ni and found that the highest NO conversion reached 85.4% at 350 °C . However, most studies were carried out under a simple reaction atmosphere, which contained only NO and CO. Few reports have examined reaction atmospheres approaching typical automobile exhaust .…”

“…[21][22][23][24] Liu et al investigated NO removal with CO over CuO-CoO x supported on Ce 0.67 Zr 0.33 O 2 , and showed that when the reaction temperature was >350 ∘ C, conversions of NO and CO both achieved 90% under the gas hourly space velocity (GHSV) of 24 000 h −1 . 25 Zhang et al synthesized a MnO x -CuO/TiO 2 catalyst modified with Ni and found that the highest NO conversion reached 85.4% at 350 ∘ C. 26 However, most studies were carried out under a simple reaction atmosphere, which contained only NO and CO. Few reports have examined reaction atmospheres approaching typical automobile exhaust. 27 Satsuma et al evaluated the activity of a Fe-Ni/CeO 2 catalyst and reported that simultaneous removal of NO, CO and C 3 H 6 was attained above 300 ∘ C. 28 Kang et al loaded Ni-Cu alloy onto Mg-Al mixed oxides and synthesized a Ni 0.3 Cu 0.2 /2MgO·1/2MgAl(2)O(4) catalyst, which showed a high catalytic activity for a simulated automotive exhaust, especially for the oxidation of HCs in a reducing atmosphere.…”