Synthesis of New Microporous Zincosilicates with CHA Zeolite Topology as Efficient Platforms for Ion‐Exchange of Divalent Cations

Abstract

There is growing interest to develop zeolite materials capable of stabilizing divalent cations such as Cu , Fe , and Ni for catalytic applications. Herein the synthesis of a new microporous zincosilicate with CHA zeolite topology is reported for the first time, by particularly focusing on the mixing procedures of the raw materials to prevent the precipitation of zinc oxides/hydroxides and the formation of impurity phases. The obtained zincosilicate CHA products possess remarkably higher ion-exchange ability for catalytically useful, divalent cations, demonstrated here using Ni as an example, compared to that of aluminosilicate and zincoaluminosilicate analogs. It is anticipated that these zincosilicate CHA materials can be an efficient platform for several important catalytic reactions. In addition, the present finding would provide a general guideline for effective substitution of other heteroatoms into the zeolite frameworks.

Zinc Containing Small‐Pore Zeolites for Capture of Low Concentration Carbon Dioxide

“…The UV/Vis diffuse reflectance (Figure 4 c) results show the formation of Zn‐O‐Zn species solely at stage III with high Zn ion loadings, [55, 56] as suggested by the appearance of the O 2− →Zn 2+ ligand‐to‐metal charge transfer transition band at ca. 360 nm [57] . Thus, Zn ions are incorporated as Zn 2+ and/or Zn(OH) + ions (Figures S16–21, with detailed discussion in Supporting Information) at stages I and II, consistent with previous research on copper ion exchange into CHA‐type zeolites [58] …”

“…360 nm. [57] Thus,Z ni ons are incorporated as Zn 2+ and/or Zn(OH) + ions (Figures S16-21, with detailed discussion in Supporting Information) at stages Ia nd II, consistent with previous research on copper ion exchange into CHA-type zeolites. [58] Quantitative analysis of the state of Zn ions (Tables 1and S6) suggests that Zn 2+ ions are the predominant species at stage I( Zn/Al 0.23) that shows high adsorption efficiency, i.e., CO 2 /Zn.…”

Zinc Containing Small‐Pore Zeolites for Capture of Low Concentration Carbon Dioxide

“…360 nm. [57] Thus, Zn ions are incorporated as Zn 2+ and/or Zn(OH) + ions (Figures S16-21, with detailed discussion in Supporting Information) at stages I and II, consistent with previous research on copper ion exchange into CHA-type zeolites. [58] Quantitative analysis of the state of Zn ions (Tables 1 and S6) suggests that Zn 2+ ions are the predominant species at stage I (Zn/Al≤ 0.23) that shows high adsorption efficiency, i.e., CO2/Zn.…”

Extremely Stable Zeolites Developed via Designed Liquid-Mediated Treatment

“…Conversely, the stability of low-silica zeolites was not improved by the same treatment, as can be seen in Figure (b). Therefore, the self-defect-healing method is not suitable for low-silica zeolites, and alternative methods such as cation exchange − and phosphorus modification , should be chosen to stabilize the framework Al species.…”