Confined Catalysis: Progress and Prospects in Energy Conversion

Abstract

Space confined catalysis has emerged as viable strategy for achieving potent and efficient catalysts in various important reactions. It offers a means of creating unique nanoscale chemical environments partitioned from the surrounding bulk space. This gives rise to the phenomena of nanoconfinement, where the energetics and kinetics of catalytic reactions can be modulated upon confining the catalysts in a particular site. Various scaffolds have been reported so far for confinement. Among these, void spaces under the cover of 2D materials, van der Waals (vdW) gaps of layered 2D materials, nanotubes, and porous surfaces have recently won copious attention. In this review, the concept of space confinement with respect to its effect on the electronic and structural properties of a catalyst is discussed. Emphasis is devoted to the catalysis of water splitting and CO2 reduction reactions. The progress in the design and applications of space confined catalysts is then traced. Finally, a discussion of emerging issues yet to be explored for this strategy to achieve a high efficiency, and future directions with the potential to become a new hotspots are presented.

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

“…Recently, many reports have shown that the confined spaces can efficiently enrich the local concentration of reactant molecules in confined spaces, which subsequently enhances the reaction rate. [17,21] However, the enriching effect of confined spaces for promoting CO x conversion is scarcely reported. Pérez-Rodríguez et al have utilized the enriching effect of confined spaces to the electroreduction of CO 2 .…”

“…On graphene@COF cathode with 47.5 % carbon content, a discharge capacity of 27833 mAh g À 1 at 75 mA g À 1 is achieved, while it retains a low charge potential of 3.5 V at 0.5 A g À 1 for 56 cycles. [64] The enrichment effect of confined spaces efficiently promotes the hydrogenation of organic substrates, [17,21] which can be proposed to promote the catalytic hydrogenation of CO x to fuels and value-added chemicals. This not only sufficiently utilizes C1 resources but also address the energy and environmental crisis simultaneously.…”

“…Confinement catalysis has been considered as a powerful tool to adjust the electronic properties and structure of catalysts, and then efficiently tune the catalytic properties. [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.…”

“…To the best of our knowledge, comprehensive review paper on promoted catalytic conversion of CO x in confined spaces is still lacking, although many review articles have been published on the preparation and applications of confinement catalysts for variety of transformations, [8,[13][14][15][16][17][18][19][20][21] and also on the designing of various catalysts for selective conversion of CO x into fuels and high-value chemicals. [2,7,[9][10][11]22,23] The present review contributes to present the advances and prospect of the catalytic conversion of CO x into fuels and value-added chemicals in confined spaces.…”

Understanding Surface Modulation to Improve the Photo/Electrocatalysts for Water Oxidation/Reduction

“…Electrocatalytic reactions typically involve multiple, successive steps occurring on the interface of a solid electrocatalyst and the electrolytes [108][109][110][111][112][113]. It is generally known that the adsorption of reactants is considered the initial step, followed by the reaction, and finally desorption for any kind of heterogeneous catalytic processes.…”