Synthesis of 3D-Ordered Macro/Microporous Yolk–Shelled Nanoreactor with Spatially Separated Functionalities for Cascade Reaction

Abstract

Constructing three-dimensional (3D) hierarchical materials with spatial compartmentalization of multiple catalytic functionalities effectively facilitates the chemical processes’ intensification, especially for bulky-molecule-involved cascade reaction. Herein, a facile and novel core–shell colloidal crystal templating strategy was developed to synthesize highly ordered arrays of integrated yolk–shelled nanoreactor consisting of monolithically interconnected ZIF-8 shell and sulfonated polystyrene yolks decorated with rhodium nanoparticles. The obtained nanoreactor achieves efficient catalytic one-pot cascade Knoevenagel condensation-hydrogenation reactions for larger molecules, by taking advantage of the superior mass diffusion properties of the hierarchical macro/microporous metal–organic framework (MOF) skeleton, robust monolith nature, and spatially separated functionalities. This work offers an important strategy for preparing MOF-based composites with a hierarchical framework, accelerating various applications of MOFs, such as electrochemical applications, photothermal conversion, and heterogeneous catalysis.

Preparation of ZIF@ADH/NAD-MSN/LDH Core Shell Nanocomposites for the Enhancement of Coenzyme Catalyzed Double Enzyme Cascade

“…The consumption of pyruvate was determined by spectrophotometry and the activity of immobilized enzyme was 1.72 times higher than that of free enzyme. The conclusion was also consistent with the theory that microporous or macroporous materials could reduce substrate diffusion and improve the efficiency of product synthesis [ 58 ].…”

“…The consumption of pyruvate was determined by spectrophotometry and the activity of immobilized enzyme was 1.72 times higher than that of free enzyme. The conclusion was also consistent with the theory that microporous or macroporous materials could reduce substrate diffusion and improve the efficiency of product synthesis [58]. The reason why the lactic acid synthesis rate of the experimental group not higher than that of the control group at the beginning may be the inhibitory effect of acetaldehyde produced in the system on enzyme activity [59].…”

In Situ Growth of ZIF-8 Nanocrystals on the Pore Walls of 3D Ordered Macroporous TiO2 for a One-Pot Cascade Reaction

“…The XRD patterns of the 3DOM TiO 2 , ZIF-8, and ZIF-8@3DOM TiO 2 are shown in Figure 3a. The XRD pattern of 3DOM TiO 2 shows three peaks at 2θ = 25.3 • , 37.9 • , and 48.0 • , corresponding to the crystal planes of (101), (004), and (200), respectively, which indicates that the TiO 2 sample adopts an anatase phase after calcination at 570 • C. In the XRD pattern of ZIF-8, the obvious peaks, including 011, 002, 112, 022, 013, and 222, are observed [11]. The diffraction pattern of ZIF-8@3DOM TiO 2 exhibits that the patterns include those of ZIF-8 and 3DOM TiO 2 , indicating that ZIF-8 NCs are dispersed in the 3DOM TiO 2 and this is consistent with the SEM results.…”

“…Therefore, it is important to develop a new method for the integration of ZIF-8 with a porous support matrix, in which ZIF-8 NCs are selectively and uniformly formed and protected in a continuous macroporous material. Specifically, the integration of ZIF-8 NCs and the macroporous material can remarkably promote the mass transfer for bulky-molecule-involved reactions and expose inside active sites [11]. Moreover, the ZIF-8 composites not only can combine the advantages but also mitigate the shortcomings of both components [12].…”

“…Wang and co-workers recently reported a composite Au@Cu(II)-MOF catalyst that can gradually promote the benzyl alcohol oxidization and Knoevenagel condensation reactions [21]. Our group has designed a bifunctional catalyst integrated with a yolk-shell structure (IY-SO 3 H/Rh@S-ZIF-8) to accomplish cascade reaction, which provides an innovative idea for preparing MOF composites with a hierarchical framework [11]. Therefore, driven by the need to continuously optimize the properties of composite materials, particular efforts are devoted to the design and formation of special structures rather than random mixtures [22].…”