Journal of Chemical Technology and Biotechnology, Vol.94, No.10, 3356-3366, 2019
Influence mechanism of different precursors on the adsorption behavior of NOx over Cu2+ ion-exchange ZSM-5
BACKGROUND The combined Adsorption-Nonthermal Plasma Catalytic process (A-NTP-C) which is used for decomposition of NOx has become a technical approach of high research value.Many studies have shown that the better the adsorption performance of the catalyst in the A-NTP-C process, the higher the conversion of NO. The type of Cu precursors will affect the chemical/physical properties of Cu-based catalysts, thus influencing the adsorption performance of catalysts. In this study, an ion exchange process was used to prepare Cu/ZSM-5 catalysts with three Cu precursors, namely copper acetate (AC-Cu), copper nitrate (N-Cu) and copper sulfate (S-Cu). Results Different Cu precursors led to differences in Cu ion exchange capacity of Cu/ZSM-5; the Cu content of AC-Cu/ZSM-5 was the highest. Furthermore, even with the same Cu content as N-Cu/ZSM-5 and S-Cu/ZSM-5, the AC-Cu/ZSM-5 catalyst showed the best adsorption performance. Conclusion X-ray photoelectron spectroscopy results indicated that CuO and isolated tetrahedron-coordinating Cu(II) were the main forms of Cu species on Cu/ZSM-5. The results of in situ DRIFTs indicated that NO was oxidized by CuO and the generated NO2 was adsorbed by H+ and isolated Cu (II). The AC-Cu/ZSM-5 catalysts had the largest amount of tetrahedron-coordinating isolated Cu (II) and the strongest H+ electrophilic ability, giving it the best NOx adsorption performance. The different precursors had little effect on the ZSM-5 structure, but did cause differences in pore volume, which might influence the adsorption capacity of NOx to some extent. These conclusions provide new ideas and methods for optimizing the adsorption capacity of Cu/ZSM-5. (c) 2019 Society of Chemical Industry (c) 2019 Society of Chemical Industry