Influence mechanism of different precursors on the adsorption behavior of NOx over Cu²⁺ ion‐exchange ZSM‐5

Abstract

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. © 2019 Society of Chemical Industry © 2019 Society of Chemical Industry

Confinement of SnCuxO2+x Nanoclusters in Zeolites for High‐Efficient Electrochemical Carbon Dioxide Reduction

“…[ 23 ] The SnCu 1.5 O 3.5 @MFI has the most wide distribution of mesopore size that is favorable for efficient transport of reactants (CO 2 , H 3 O + , Li + ) and products (methane, C 2 H 4 , H 2 , Li 2 CO 3 /C) in MFI zeolite channels for electrocatalytic CO 2 reduction and conversion. [ 24 ] The wide pore size distribution observed in the as‐prepared SnCu x O 2+ x @MFI catalysts may be attributed to the different ratio of copper to tin contents which affect the in situ formation of micropores/mesopores and the growth of MFI zeolite frameworks.…”

“…− and achieve protonation in the CO 2 RR process. [ 24 ] The Sn 3d XPS spectra of the zeolite‐based catalysts with Sn component are shown in Figure S34, Supporting Information. The separated peaks centered at binding energy of ≈488 and ≈497 eV are assigned to the 3d5/2 and 3d3/2 of Sn 3d, respectively.…”

Enhanced Adsorption Desulfurization Performance over CuCeY Zeolites Prepared by Low‐Temperature Calcination under H2 Atmosphere

“…The binding energies (BEs) at 932.4, 933.9, 935.1 Figure 11 are the characteristic peaks of Cu + ion, tetrahedrally coordinated Cu 2 + ions, octahedrally coordinated Cu 2 + ions and the Cu 2p 1/2 , respectively. [67,[71][72][73] It's worth noting that the BE of characteristic peak of Cu 2 + ion in the CuO species is also between 933.4 and 934.0 eV. [64,[73][74][75] Hence, it is difficult to determine the content of the CuO species.…”

Structural Analysis of Cu+ and Cu2+ Ions in Zeolite as a Nanoreactor with Antibacterial Applications

“…Zeolite has oxide-reduction capacity, which can produce Cu 2+ , Cu , + and metallic Cu, , including clusters of Cu 3+ . Studies have been carried out on the ion exchange of Cu 2+ in zeolites ZSM-5, Y, CHA, X, RTH, and LTA − and Cu + has been studied in ZSM-5, CHA, and BEA − independently. A recent investigation of copper mono- and polystructures obtained in a ZSM-5 zeolite has revealed how the copper species interact with the zeolite, as well as precisely observing their positions within the zeolite structure .…”