Graphite felt-supported Mn catalysts for low-temperature NH₃-SCR

Traditional Mn-based NH₃-SCR catalysts have a narrow temperature window, limiting low-temperature use. In this work, Mn@N-7 was prepared by a simple hydrothermal method using potassium permanganate and urea. The hydrothermal conditions are much milder than those used for most Mn-based catalysts. Graphite felt (GF) serves as a green support, providing a 3D carbon fiber network for uniform growth of manganese oxide nanowebs. Its high surface area (83.10 m² g⁻¹) and open channels promote active species dispersion and fast mass transfer. The strong carbon framework prevents sintering at high temperatures. Mn@N-7 shows nearly 100% NO conversion at 100–200 °C and maintains good activity for 30 h. Its estimated cost is 1.2–1.8 USD kg⁻¹, lower than 3.0–4.5 USD kg⁻¹ for V₂O₅-WO₃/TiO₂ catalysts. The mild hydrothermal process avoids high-temperature calcination. This work demonstrates GF is a sustainable support and offers guidance for carbon-based catalysts in clean air applications.