As discussed above we find a increasing

Additionally, DOS of both reactant and product as a whole shifts to right, demonstrating both the reactant and product are raised to higher energy level in the presence of O2. The enthalpy of reaction of NO2 with CH4 in the presence of O2 is −195.53 kcal mol−1, which is larger than that in the absence of O2. Finally, this work reveals that adsorbed O2 reduces the activation energy and causes a lowering of SCR reaction temperature.