Design and Synthesis of Powerful Capsule Catalysts Aimed at Applications in C1 Chemistry and Biomass Conversion

Abstract

Tandem catalytic reaction is a promising strategy to improve the utilization efficiency of energy and resources. The conventional hybrid catalysts cannot readily realize the precisely controlled synthesis of target products due to the unrestricted, open reaction environment. Assembling the hybrid catalyst with multiple active sites into core-shell structured capsule catalyst is one of the most effective ways to enhance the selectivity of desired products during a tandem catalysis process, because the core-shell structure offers a space-confined reaction field and synergistic effect. This review describes our recent progresses on the design and synthesis of coreshell structured zeolite capsule catalysts developed for C1 chemistry and biomass conversion. The various synthesis methods for constructing the well-defined zeolite capsule catalysts are described in detail. The applications of the capsule catalysts in catalysis, including the middle isoparaffins synthesis from syngas, one-step synthesis of dimethyl ether, and liquid-phase tandem reaction of glycerol conversion, are discussed, respectively. Our perspectives regarding the challenges and opportunities for future research in the field are also provided.

Catalytic Conversion of Carbon Oxides in Confined Spaces: Status and Prospects

“…The restrained sintering and coking by confined spaces are extensively investigated and applied to diverse reactions including but not being limited to CO x conversion. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] The intensified metal-support interaction by confinement effect can inhibit the formation of shell carbon, and therefore, the accessibility of active sites is not depressed. As a consequence, the catalytic activity can be maintained during the reaction.…”

“…As is mentioned as above, till now, many efforts have been made on developing highly-efficient and practical catalysts with outstanding catalytic activity, selectivity, and stability for CO x transformations, but it remains a challenge. From references, [2,[7][8][9][10][11][12]22,23] the catalysis in confined spaces has been regarded as a powerful strategy for improving catalytic activity, selectivity, and stability of heterogeneous catalysts for CO x conversion. Generally, the improving effect of thus confined spaces has been defined as the "confinement effect".…”

“…The well-organized core-shell structure intensities the tandem reaction owing to confinement effect, which efficiently improves the selectivity. [8][9][10][11][12]21,83] In fact, this is one kind of unique self-regulation strategy. For clear presentation, in this section, the related studies are divided into two parts: CO x to hydrocarbon and CO x to oxygen-containing compounds.…”

“…[1][2][3][4][5][6][7] The selectively catalytic transformation of carbon oxide (CO x , including CO 2 and CO) into fuels and highvalue chemicals has attracted much attention in recent years. [3][4][5][6][7][8][9][10][11][12] Recently, although extensive studies have been devoted to catalytic transformation of CO x , the state-of-the-art development of catalysts for thus transformations of CO x to fuels and value-added chemicals for industrial applications is far from satisfactory. The further improvement in catalytic activity, selectivity, and stability, especially selectivity, is highly desirable.…”

“…[8,[14][15][16][17][18][19][20][21][22][23] Currently, confinement catalysis has been extensively applied to the catalytic conversion of CO x regarding of improvement in catalytic activity, selectivity, and stability (Scheme 1). [9][10][11][12][24][25][26] Especially, the confined spaces of catalysts efficiently improve the catalytic selectivity for CO x conversion into fuels and high-value chemicals through the modulation of active sites and also the products self-regulation by the confined shell, which represents a promising direction for the selective conversion and utilization of carbon oxides.…”