Cu‐Fe/activated carbon catalyst for low‐temperature CO‐selective catalytic: Modification and denitration mechanism

Abstract

AbstractTo study the Cu‐Fe modification and CO denitration mechanism of carbon‐based sorbent, coconut‐husk activated carbon (AC), which was activated via air thermo‐oxidation and modified using Cu(NO3)2 and Fe(NO3)2 was examined. In addition, the denitration activity was evaluated. The effects of air thermo‐oxidative activation, as well as Cu(NO3)2 and Fe(NO3)2 immersion on the pore texture and surface characteristics of the carbon materials, were examined by scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) analysis, X‐ray powder diffraction (XRD) and Fourier‐transform infrared (FTIR) spectroscopy. The reduction performance and CO adsorptive property of xCu‐yFe/AC catalyst was measured using hydrogen temperature‐programmed reduction (H2‐TPR) and carbon monoxide temperature‐programmed desorption (CO‐TPD). The xCu‐yFe/AC's denitration activity showed that physical adsorption is a priority, then chemical adsorption recovers the denitration activity after physical adsorption saturation. The modification mechanism showed that higher loading of Cu and Fe resulted in enhanced dispersivity and more active sites but decreased specific surface area and pore volume. Then, the capability of physical adsorption decreased. Moreover, higher Fe loading was conducive to improved dispersivity of copper oxide species. The effects of Cu and Fe modification on the majority of functional groups were insignificant. The reduction peak at approximately 150°C indicated that the xCu‐yFe/AC catalyst has strong reduction characteristics. The number of CO active adsorption sites increased by high loading quantity at high‐temperature. The CO‐selective catalytic reduction (SCR) denitration conforms to Langmuir–Hinshelwood mechanism. The reciprocal transformation between Fe2+ and Fe3+, Cu+ and Cu2+, which is conducive to the rapid progress of the CO‐SCR reaction.