Low-Temperature Selective Catalytic Reduction Of NO Over MnO_x-CeO₂Supported On Pitch-based Spherical Activated Carbon

Nitrogen oxides (NOx) are a major source of atmospheric pollutions, which do harm to environment and human health. Selective catalytic reduction (SCR) is usually used to achieve the efficient removal of nitrogen oxides.Pitch-based spherical activated carbon (PSCA), carbon aerogel (CA) and SBA15molecular sieve supported Mn-Ce were prepared by wet impregnation method, and the SCR activity of three different supports was studied. The results showed that400-8(Mn-Ce)-PSAC sample exhibited the highest catalytic activity, and NOx conversion was almost100%under the conditions of500ppmv NO,500ppmv NH3,8vol%O2,5000h-1and130℃. Such a high activity of the catalysts prepared with PSAC as support may be primarily attributed to its high specific surface area and micropore structure.Furthermore, low-temperature selective catalytic reduction of NO with melamine supported on PSAC based catalysts was investigated, which would avoid problems caused by NH3as a reducing agent, such as secondary pollution. It was found that400-8(Mn-Ce)-PSAC-10mel exhibited98%NOx removal rate within the initial5h under the conditions of500ppmv NO,8vol%O2,5000h-1and190℃. In-situ infrared technology was used to study the effect of O2on the melamine-SCR, and the results showed that the presence of O2promoted the oxidation and adsorption of NO, and facilitated the reaction between adsorbed NOx and intermediate products of reducing agent.