Bimetallic Catalysts on Activated Carbon for Enhanced NO Reduction

Reducing emissions of nitrogen compounds represents a significant challenge in environmental protection, and catalytic treatment is an effective approach. Carbon-based catalysts offer a promising alternative by exploiting the redox properties of carbon materials and eliminating the need for external reducing agents. In this study, nitrogen-free and nitrogen-doped activated carbons were used for NO reduction. The catalysts were developed by incorporating transition metals (Cu and Fe), alkali metals (K), and bimetallic Cu-K formulations. The addition of K to Cu and the presence of nitrogen functionalities improved the catalytic performance and an optimum Cu/K ratio was identified. The best-performing catalyst, AC_M_BM@5Cu5K, achieved 100% NO conversion at 410 °C, producing mainly N2 and CO2, while N2O was detected as an intermediate and CO was not observed. The catalyst’s stability was evaluated in a 100 h continuous test at 376 °C, during which the catalyst maintained approximately 90% NO conversion for 40 h before deactivation. The deactivation mechanism is discussed in detail.