Modular Polyoxometalate‐Layered Double Hydroxide Composites as Efficient Oxidative Catalysts

Abstract

Abstract:The exploitation of intercalation techniques in the field of two-dimensional layered materials offers unique opportunities for controlling chemical reactions in confined spaces and developing nanocomposites with desired functionality. In this paper, we demonstrate the exploitation of the novel and facile 'one-pot' anionexchange method for the functionalization of layered double hydroxides (LDHs). As a proof of concept, we demonstrate the intercalation of a series of polyoxometalate (POM) clusters, Na3[PW12O40]·15H2O (Na3PW12), K6[P2W18O62]·14H2O (K6P2W18), and Na9LaW10O36·32H2O (Na9LaW10) into tris(hydroxymethyl)aminomethane (Tris) modified layered double hydroxides (LDHs) under ambient conditions without the necessity of degassing CO2. Investigation of the resultant intercalated materials of Tris-LDHs-PW12 (1), Tris-LDH-P2W18 (2), and Tris-LDH-LaW10 (3) for the degradation of methylene blue (MB), rhodamine B (RB) and crystal violet (CV) has been carried out, where Tris-LDH-PW12 reveals the best performance in the presence of H2O2. Additionally, degradation of a mixture of RB, MB and CV by Tris-LDH-PW12 follows the order of CV > MB > RB, which is directly related to the designed accessible area of the interlayer space. Also, the composite can be readily recycled and reused at least ten cycles without measurable decrease of activity.

Polyoxometalate (POM)-Layered Double Hydroxides (LDH) Composite Materials: Design and Catalytic Applications

“…Recently, a series of POM-intercalated LDHs (Tris-LDHs-PW12, Tris-LDH-LaW10 and Tris-LDH-P2W18) were prepared by employing the host layer modification method under ambient conditions without the necessity of degassing CO2. The heterogeneous catalytic systems were used for the efficient degradation of methylene blue (MB), rhodamine B (RB) and crystal violet (CV) solution, where Tris-LDHs-PW12 exhibits the best performance in the presence of H2O2 [46]. As shown in Figure 7, almost complete dye degradation can be achieved within 320 min, 140 min, and 5 min for RB, MB, and CV, respectively.…”

“…In recent years, POM-LDH composites have been widely used in green chemistry industry [40,46], and currently, catalytic oxidation desulfurization has become an important task for environmental pollution control. However, the traditional Water pollution from dyes is a serious environmental problem due to the inherent difficulties for their efficient degradation in conjunction with their high chemical stability [45].…”

“…The heterogeneous catalytic systems were used for the efficient degradation of methylene blue (MB), rhodamine B (RB) and crystal violet (CV) solution, where Tris-LDHs-PW 12 exhibits the best performance in the presence of H 2 O 2 [46]. As shown in Figure 7, almost complete dye degradation can be achieved within 320 min, 140 min, and 5 min for RB, MB, and CV, respectively.…”

“…On the basis of increasing environmental impact of sulfur-containing chemicals in fuel oils, the development of efficient and environmentally friendly deep desulfurization processes has been flagged as an urgent global challenge [47,48]. In recent years, POM-LDH composites have been widely used in green chemistry industry [40,46], and currently, catalytic oxidation desulfurization has become an important task for environmental pollution control. However, the traditional hydro-desulfurization (HDS) processes employed for the removal of DBT, 4,6-DMDBT and BT etc.…”

Self-Assembly in Polyoxometalate and Metal Coordination-Based Systems: Synthetic Approaches and Developments

“…The formation of LDH-based materials is driven by weak interlayer interactions, and as a consequence, they offer an excellent opportunity for the development of composite compounds by exchanging the anionic and solvent content of the interlayer cavities with the desirable components. For example, exploitation of supramolecular interactions between the LDH layers and POM clusters, have given a wide range of materials with interesting catalytic properties tailored for applications in epoxidations, N-oxidations and desulfurisations [88][89][90][91][92]. …”