Study on the Influence of Manganese Element Doping on Vanadium-based Catalysts

The performance of on-board SCR catalysts has been in high demand due to the increasingly stringent vehicle emission requirements. Diesel engines typically have exhaust gas temperatures below 250°C at cold start and idling; the catalyst carrier's actual temperature field is uneven, with high-temperature areas ranging from 430 to 530°C; and high-temperature exhaust gas is also produced during DPF regeneration. Thus, the development of composite metal oxide catalysts with a broad temperature window is the goal of this effort. Using the solution combustion method, vanadium-based SCR catalysts supported by manganese were created. Their chemical structure, performance, and physical characteristics were then examined and described. It was discovered that adding Mn significantly increased the catalyst's low-temperature activity while marginally impairing its high-temperature performance. Between 190°C and 440°C, the TiV _0.1 Mn _0.1 O _x catalyst with r = 0.1 performed the best, retaining over 80% activity and selectivity. Mn doping had no discernible impact on the specific surface area, pore volume, or pore diameter, according to BET characterization. The XRD patterns only showed anatase TiO₂ diffraction peaks, suggesting that the active ingredients were widely distributed across the carrier surface. The total acid quantities on the four catalysts' surfaces were comparable, according to NH₃-TPD curves, and the distribution of acid amounts moved to lower temperatures as the Mn content increased. Some catalysts experienced sintering problems, according to TEM pictures, but their surfaces featured rich pore architectures.