Cobalt doped Fe-Mn@CNTs catalysts with highly stability for low-temperature selective catalytic reduction of NO_x

In this paper, we report the fabrication of cobalt-doped de-NO_x catalyst by pyrolyzing an analogous metal-organic framework-74 (MOF-74) containing Fe & Mn. The resulted catalyst exhibits distinctive microstructures of manganese, cobalt, and iron immobilized on N-doped carbon nanotubes (CNTs). It is found through experiments that the trimetallic catalyst Fe ₂Mn₁Co_0.5/CNTs-50 has the best NH₃-selective catalytic reduction (SCR) performance. The Fe₂Mn₁Co_0.5/CNTs-50 exhibited excellent water and sulfur resistance and good stability under the harsh gas environment of 250 °C and/or 170 °C, NO = NH₃ = 1,000 ppm, 8 vol.% O₂, 20 vol.% H₂O, 1,000 ppm SO₂, and gas hourly space velocity (GHSV) = 75,000 h⁻¹. The de-NO_x conversion was maintained about 55% and 25% after 192 h. The water and sulfur resistance performance were much higher than commercial vanadium series catalyst. The highly water and sulfur resistance performance may be attributed to the unique core–shell microstructure and the synergistic effect of manganese, cobalt, and iron which helps reduce the formation for by-products (NH₄HSO₄). This study may promote to explore the development of a high stability catalyst for low-temperature selective catalytic reduction of NO_x with NH₃.