A comprehensive review on the synthesis techniques of porous materials for gas separation and catalysis

Abstract

Intrinsic structural characteristics of porous materials have found significant applications in selective separation of gases and heterogeneous catalysis. While using porous materials for gas separation and catalysis, some of the challenging issues are the strength of catalytic sites, hydrothermal stability, crystalline order of solids, and selectivity. Researchers' ability to engineer the synthesis strategies rationally can help overcome technological challenges. In recent years, breakthroughs in porous materials are focused on developing different chemistries to control the pore architecture. This review focuses on recent advances made in synthesis strategies of porous materials and their impact on gas separation and catalysis applications. A significant part of this review is devoted to various synthesis methods, such as various types of templating methods, molecular layer deposition, sol-gel technique, and polymerization methods. Improvement in various catalytic reactions and gas separations due to different functionalization methods is also summarized. Lastly, we have discussed the applications of porous materials in the form of adsorbents and membranes in commercial processes. We hope that this review will serve as a quick reference for beginners who want to synthesize porous materials with control of pore structure.

Surfactant-free gelatin-stabilised biodegradable polymerised high internal phase emulsions with macroporous structures

“…For example, in tissue engineering this enables cell ingrowth; in filters, interconnectivity facilitates mass transport and for electrode substrates and catalysts high surface areas result in a better current and substrate conversion, respectively ( Chong et al, 2019 ; Elango et al, 2021 ; Fager et al, 2021 ; Vásquez et al, 2021 ; Maksoud et al, 2022 ; Mravljak et al, 2022 ). There are numerous methods of introducing porous geometries within polymers, including bioprinting, particulate leaching, freeze drying, electrospinning and emulsion templating ( Eltom et al, 2019 ; Sharma et al, 2022 ). Emulsion templating is a relatively simple technique that can be easily tuned to control and influence the resulting structures.…”

Crystalline micro and mesoporous materials for applications in heterogeneous catalysis: the evolution of materials

“…Over the years, different reactions have been studied to investigate these factors in surface reactions. 6,[8][9][10] In this highlight, we focus on our recent efforts in considering the role of meso and microporous materials in heterogenous catalytic reactions, highlighting some examples of these materials used in industrial and chemical-relevant reactions, emphasising on the transition from "classic" to "novel" materials.…”

“…Some benefits of heterogeneous catalysts over homogeneous catalytic materials are: i) heterogeneous catalysts operate in batch and continuous production systems, whereas homogeneous catalysts are limited to batch reactors, ii) separating the solid heterogeneous catalyst from the reaction mixture is more accessible than the homogeneous liquid catalyst because the heterogeneous catalysts can be filtered with ease, iii) in heterogeneous catalysis, the reaction temperature can be as elevated as the process conditions need, using a suitable solid catalyst, as opposed to homogeneous catalysis, where the boiling point of its components limits it, iv) solid heterogeneous catalysts can easily lead to sustainable reactions as the catalyst is recoverable and rarely requires a high pH adjustment at the end of the reaction, and v) most heterogeneous catalysts are non-corrosive and can be used as they are in any reactor; in contrast, homogeneous catalysts request corrosive-resistant reactors. 6,7 On the other hand, these advantages as heterogeneous catalysts due to their composition and structure, at the same time, limit them. Meso- and micro-porous materials as catalysts have a structure that can be complex and a pore size that can limit diffusion and affect reaction conversion.…”

“…Over the years, different reactions have been studied to investigate these factors in surface reactions. 6,8–10…”

Hexnuclear, octanuclear, dodecanuclear, and hexadecnuclear polyoxomolybdenum(v)-based porous materials for selective adsorption of gases

“…Porous crystal materials have attracted extensive attentions in the fields of adsorption, catalysis and ion exchange due to their structural adjustability, chemical stability and feasibility of hybridization with other materials, 1,2 where polyoxometalate-based porous complexes are also involved. 3 This is because polyoxometalates are excellent multifunctional materials with variable structures, well-definite sizes and shapes, adjustable acidity, abundant redox properties, etc.…”