Advances in Microwave Synthesis of Nanoporous Materials

Abstract

Usually, porous materials are synthesized by using conventional electric heating, which can be energy‐ and time‐consuming. Microwave heating is commonly used in many households to quickly heat food. Microwave ovens can also be used as powerful devices in the synthesis of various porous materials. The microwave‐assisted synthesis offers a simple, fast, efficient, and economic way to obtain many of the advanced nanomaterials. This review summarizes the recent achievements in the microwave‐assisted synthesis of diverse groups of nanoporous materials including silicas, carbons, metal–organic frameworks, and metal oxides. Microwave‐assisted methods afford highly porous materials with high specific surface areas (SSAs), e.g., activated carbons with SSA ≈3100 m2 g−1, metal–organic frameworks with SSA ≈4200 m2 g−1, covalent organic frameworks with SSA ≈2900 m2 g−1, and metal oxides with relatively small SSA ≈300 m2 g−1. These methods are also successfully implemented for the preparation of ordered mesoporous silicas and carbons as well as spherically shaped nanomaterials. Most of the nanoporous materials obtained under microwave irradiation show potential applications in gas adsorption, water treatment, catalysis, energy storage, and drug delivery, among others.

Tailoring a robust Al-MOF for trapping C2H6 and C2H2 towards efficient C2H4 purification from quaternary mixtures

“…The microwave heating enables faster nucleation that helps the formation of smaller particle sizes with an increased surface-to-volume ratio. 44 Additionally, the mixed solvent duo, water–ethanol clusters act as templates for additional mesopore formation and corresponding hierarchical porosity in the framework. 45 This investigation unfolds the impact of reaction time, ranging from 5 to 220 minutes, wherein the MOF produced with 15 minutes (Al-MOFM 15 ) of reaction time showed the maximum surface area (BET; 793 m 2 g −1 ) with the highest micro–mesopore volume ratio.…”

Recent Advancements in the Fabrication of Functional Nanoporous Materials and Their Biomedical Applications

“…When microwave irradiation is exposed to a precursor material, the temperature increases upon microwave penetration (conversion of microwave energy to heat). The origin of microwave heating is caused by two mechanisms: ionic conduction (oscillation of cations or anions back and forth) and dipolar polarization (fluctuations/rotations of dipoles) [ 34 ]. Microwave heating increases the temperature of the reaction mixture (not vessel) uniformly as compared with conventional methods of heating, which are slow and nonuniform.…”

“…These strategies have been used to fabricate ordered, disordered, and hierarchical nanoporous materials with tunable pore sizes, shapes, and relative orientation of pores at different length scales. In recent years, several reviews published on nanoporous materials have primarily focused on selective modification of nanoporous materials, synthesis, and characterization of specific types of nanoporous materials and their applications [ 8 , 17 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 ]. Indeed, the field of nanoporous materials is progressing at a rapid pace with more emphasis on developing new fabrication strategies.…”

Rapid, energy-efficient and pseudomorphic microwave-induced-metal-plasma (MIMP) synthesis of Mg2Si and Mg2Ge

“…Simultaneously, the major benefits of time/energy savings; rapid heating rates; fast throughput; precise, selective heating, and reduction of waste heat/hazardous chemicals have been delivered. [2][3][4][5][6][7][8][9][10][11] Nevertheless, MW synthesis still faces many challenges before its implementation as a primary route to advanced materials manufacturing could be considered. [2][3][4][5][6][7]10 The Mg 2 X (X = Si, Ge, Sn) family crystallises with the facecentered cubic, antifluorite structure (space group Fm-3m) in which Mg atoms occupy the 8c (1/4, 1/4, 1/4) interstitial sites within a CCP lattice of X atoms (4a sites; Figure 1b).…”

“…[2][3][4][5][6][7][8][9][10][11] Nevertheless, MW synthesis still faces many challenges before its implementation as a primary route to advanced materials manufacturing could be considered. [2][3][4][5][6][7]10 The Mg 2 X (X = Si, Ge, Sn) family crystallises with the facecentered cubic, antifluorite structure (space group Fm-3m) in which Mg atoms occupy the 8c (1/4, 1/4, 1/4) interstitial sites within a CCP lattice of X atoms (4a sites; Figure 1b). 5,12 These Zintl phase compounds are intrinsically n-type semiconductors with narrow indirect band gaps (e.g.…”