Generation of multi-valence CuxO by reduction with activated semi-coke and their collaboration in the selective reduction of NO with NH3

Abstract

Multi-valence Cu_xO has been demonstrated to have high activity in the low-temperature selective catalytic reduction of NO_x with NH₃ (NH₃-SCR). Here, Cu_xO was loaded onto activated semi-coke (ASC) for SCR, which has shown satisfactory low-temperature SCR activity. By virtue of the reduction property of carbon, the valence of Cu was regulated by simply adjusting the calcination temperature. The high concentration of Cu⁺ generated from the reduction of CuO by ASC during calcination can collaborate to form Cu²⁺/Cu⁺ circulation. After systematic characterization by XPS, H₂-TPD, and NH₃-TPR, it is revealed that abundant acidic sites and surface reactive oxygen species are formed on the surface of the catalysts. Further investigation with in situ DRIFTS confirms that the NH₃-SCR over the as-prepared CuO|Cu₂O-ASC catalysts simultaneously follows the Langmuir–Hinshelwood (L–H) and Eley–Rideal (E–R) pathways, attributed to the synergistic effects of Cu²⁺ and Cu⁺.