Research progress of NH3-SCR over carbon-based catalysts for NOx removal

Abstract

NOx emission is the main cause of acid rain, photochemical smog, and so on. These have seriously affected the ecological environment, production and life. Therefore, how to effectively reduce NOx emissions has become an important topic. Among many technologies of DeNOx, selective catalytic reduction (SCR) is the main research direction in recent years due to its high DeNOx efficiency. Catalyst is the key factor for SCR. Carbon-based materials are widely used as catalyst carriers because of their large surface area (700–1800 m2/g), well-developed pore structure (0.5–0.8 cm3/g) and strong adsorption capacity. At low temperatures (150 ℃−250 ℃), the NO conversions of many carbon-based catalysts can reach over 95%. Some catalysts have an N2 selectivity of more than 95% below 200 ℃. In this paper, recent research achievements of activated carbon (AC), carbon nanotubes (CNTs), graphene (GR) and other carbon materials as SCR catalyst carriers are reviewed. Meanwhile, the catalytic efficiency of the catalyst is summarized. Due to their different modification methods, preparation methods and active substances, the remarkable differences in carbon-based catalysts are summarized, and the effects of H2O and SO2 on catalysts are also discussed. The problems in the industrial application of catalysts based on carbon materials and the future research direction are pointed out.