A New Robust Ce-Ga/H-ZSM-5 Catalyst for Enhanced Selective Catalytic Reduction of Nitric Oxide by Methane

Performance of silica-supported copper oxide sorbents for SO x/NO x-removal from flue gas : II. Selective catalytic reduction of nitric oxide by ammonia

Mechanism of selective catalytic reduction of NO in the presence of excess O 2 over Pt/Si-MCM-41 catalyst

Catalytic reduction of nitrous oxide by hydrocarbons over a Fe-zeolite monolith under fluidised bed combustion conditions

IR studies on the reduction of nitric oxide with ammonia over MFI-ferrisilicate

30-P-28-Selective catalytic reduction of NO by methane over AgNaZSM-5 catalysts in the excess of oxygen

The reaction mechanisms of selective catalytic reduction (SCR) of nitric oxide (NO) by methane (CH4) over solid superacid-based catalysts were proposed and testified by DRIFTS studies on transient reaction as well as by kinetic models. Catalysts derived from different supports would lead to different reaction pathways, and the acidity of solid superacid played an important role in determining the reaction mechanisms and the catalytic activities. Higher ratios of Bronsted acid sites to Lewis acid sites would lead to stronger oxidation of methane and then could facilitate the step of methane activation. Strong Bronsted acid sites would not necessarily lead to better catalytic performance, however, since the active surface NOy species and the corresponding reaction routes were determined by the overall acidity strength of the support. The reaction routes where NO2 moiety was engaged as an important intermediate involved moderate oxidation of methane, the rate of which could determine the overall activity. The reaction involving NO moiety was likely to be determined by the step of reduction of NO. Therefore, to enhance the SCR activity of solid superacid catalysts, reactions between appropriate couples of active NOy species and activated hydrocarbon intermediates should be realized by modification of the support acidity.

Kinetic studies of selective catalytic reduction of nitric oxide by propylene on Pt/MCM-41 catalyst

Kinetics of selective catalytic reduction of NO by NH 3 on Fe-Mo/ZSM-5 catalyst

CeO2 nanorods impregnated with 2.5 atom % of NiO (NiO/CeO2 nanorods) were successfully synthesized and examined as catalysts for the NH3-selective catalytic reduction (NH3-SCR) of nitric oxide (NO). The catalytic activity of NiO/CeO2 nanorods resulted in up to ∼90% NO conversion at 250 °C, which is superior to that of pure CeO2 nanorods or NiO nanoparticles. Subsequently, extensive studies of the NiO/CeO2-catalyzed reduction of NO were conducted using X-ray photoelectron spectroscopy, hydrogen temperature-programmed reduction, temperature-programmed desorption, and density functional theory periodic calculations. Compared to that of the pure CeO2 nanorods, the results demonstrated that the NiO/CeO2 nanorods resulted in (i) a higher concentration of Ce3+ chemical species, (ii) a larger amount of active Oα, (iii) lower temperature reducibility, (iv) a lower amount of energy required for oxygen vacancy distortion, and (v) a significant adsorption of and strong interaction between NO and NH3 molecules. Our findings therefore elucidated considerable details of the structural properties of the NiO/CeO2 nanorods that were decisive for achieving a highly efficient conversion of NO by the NH3-SCR process at low temperatures.

Dielectric barrier discharge (DBD) could generate non-thermal plasma (NTP) with the advantage of fast reactivity and high energy under atmosphere pressure and low-temperature. The presented work investigated the selective catalytic reduction (SCR) of nitric oxide (NO) using a combination of NTP and an Mn-Cu/ZSM5 catalyst with ammonia (NH3) as a reductant. The experimental results illustrate that the plasma-assisted SCR process enhances the low-temperature catalytic performance of the Mn-Cu/ZSM5 catalyst significantly, and it exhibits an obvious improvement in the NO removal efficiency. The reaction temperature is maintained at 200 °C in order to simulate the exhaust temperature of diesel engine, and the 10% Mn-8% Cu/ZSM5 catalyst shows the highest NO removal performance with about 93.89% at an energy density of 500 J L−1 and the selectivity to N2 is almost 99%. The voltage, frequency and energy density have a positive correlation to NO removal efficiency, which is positively correlated with the power of NTP system. In contrast, the O2 concentration has a negative correlation to the NO removal, and the NO removal efficiency cannot be improved when the NO removal process reaches reaction equilibrium in the NTP system.

Carbon deposition enhanced selective catalytic reduction of nitric oxide by a new catalytic process as well as increasing reducibility of catalyst

Kinetics for the selective catalytic reduction (SCR) of nitric oxide (NO) using i-C4H10 as the reducing agent over Pt-Cu-ZSM5 has been investigated in the temperature range of 200 ?C – 450 oC. Langmuir-Hinshelwood-Hougen-Watson model was proposed for kinetics of the reaction and reaction parameters were evaluated. The heat of adsorption of NO was found to be considerably high, attributed to strong covalent bond between NO gas molecules and metal active sites. Using reaction parameters obtained from the experiment, the heterogeneous model could form a good correlation between experimental and simulated values of NO reduction. Key Words: Reaction kinetics, Selective catalytic reduction, NO reduction, Bimetallic catalyst, H-ZSM-5 zeolite.

Selective catalytic reduction of NO with propane over CoZSM-5 containing alkaline earth cations

In Situ FTIR Studies of the Selective Catalytic Reduction of NO by C3H6 over Pt/Al2O3

Activity and selectivity of pure manganese oxides in the selective catalytic reduction of nitric oxide with ammonia