Metal–Organic‐Framework‐Based Catalysts for Photoreduction of CO₂

Abstract

Photoreduction of CO into reusable carbon forms is considered as a promising approach to address the crisis of energy from fossil fuels and reduce excessive CO emission. Recently, metal-organic frameworks (MOFs) have attracted much attention as CO photoreduction-related catalysts, owing to their unique electronic band structures, excellent CO adsorption capacities, and tailorable light-absorption abilities. Recent advances on the design, synthesis, and CO reduction applications of MOF-based photocatalysts are discussed here, beginning with the introduction of the characteristics of high-efficiency photocatalysts and structural advantages of MOFs. The roles of MOFs in CO photoreduction systems as photocatalysts, photocatalytic hosts, and cocatalysts are analyzed. Detailed discussions focus on two constituents of pure MOFs (metal clusters such as Ti-O, Zr-O, and Fe-O clusters and functional organic linkers such as amino-modified, photosensitizer-functionalized, and electron-rich conjugated linkers) and three types of MOF-based composites (metal-MOF, semiconductor-MOF, and photosensitizer-MOF composites). The constituents, CO adsorption capacities, absorption edges, and photocatalytic activities of these photocatalysts are highlighted to provide fundamental guidance to rational design of efficient MOF-based photocatalyst materials for CO reduction. A perspective of future research directions, critical challenges to be met, and potential solutions in this research field concludes the discussion.

Molecular Porous Photosystems Tailored for Long‐Term Photocatalytic CO2 Reduction

“…The apparent quantum efficiency (AQE), determined in the region of visible light between 420 and 700 nm, increases from about 0.5 % for Cp*Rh@PyBpyCMP to about 1 % for Cp*Rh@PerBpyCMP (Figure a; Supporting Information, Table S8). These values are in line with reported AQE data for other heterogeneous photocatalytic CO 2 reduction systems containing metal‐based dyes (Supporting Information, Table S9, and further discussions therein) …”

“…These values are in line with reported AQEd ata for other heterogeneous photocatalytic CO 2 reduction systems containing metal-based dyes (Supporting Information, Table S9, and further discussions therein). [42] To assess the importance of tethering together the photosensitizer and the catalyst and to construct af ully heterogeneous photosystem, we compared Cp*Rh@PerBpyCMP to homogeneous and bi-molecular photosystems ( Table 1; Supporting Information, Scheme S2). Thehighest catalytic activity was indeed achieved using Cp*Rh@PerBpyCMP,reaching aT OF of 6h À1 .T his superior catalytic activity is most likely linked to amore extended process of quenching of the excited state and electron transport in the fully heterogeneous photosystems than in the homogeneous and bi-molecular photosystems.…”

Nickel Metal–Organic Framework Monolayers for Photoreduction of Diluted CO2: Metal‐Node‐Dependent Activity and Selectivity

“…Metal–organic frameworks (MOFs), a class of inorganic–organic hybrid materials composed of high‐density metal nodes and tailorable bridging organic ligands, are emerging as promising catalysts for CO 2 photoreduction . Although MOF‐based catalysts for CO 2 photoreduction have been widely reported, research on photocatalytic conversion of diluted CO 2 over MOFs is still in its infancy.…”

Black Phosphorus, a Rising Star 2D Nanomaterial in the Post‐Graphene Era: Synthesis, Properties, Modifications, and Photocatalysis Applications

“…The smartest long‐term solution to solve these two problems is to convert pollutants into useful fuels with the aid of renewable energy . Photocatalysis technique using solar energy as driving force is a promising technology that can convert CO 2 into fuels such as CO, CH 4 , CH 3 OH, C 2 H 5 OH, and HCHO, and much effort have been devoted in this field . Up to now, many traditional and novel photocatalysts have been developed for catalytic CO 2 reduction, which include TiO 2 , CdS, g‐C 3 N 4 , Bi 12 Cl 17 O 2 , perovskite, and metal–organic frameworks …”