Tailored Persistent Radical‐containing Heterotrimetal‐Organic Framework for Boosting Efficiency of Visible/NIR Light‐driven Photocatalytic CO₂ Reduction

Abstract

Promoting light absorption range of photocatalysts is of great significance to improve solar light‐driven photocatalytic CO2 reduction efficiency. Herein, a new viologen‐based multicomponent heterotrimetallic metal–organic framework (MOF) [Cu3Th6(µ3‐O)4(µ3‐OH)4(cpb)12][FeIII(CN)6]6 (IHEP‐14) with an unprecedented (6, 18)‐connected she‐d topology is presented. Upon UV irradiation, this MOF undergoes ligand and iron photoreduction, and a single‐crystal‐to‐single‐crystal transformation to generate persistent radical‐containing MOF [Cu3Th6(µ3‐O)4(µ3‐OH)4(cpb•)12][FeII(CN)6]6 (IHEP‐15). This radical‐containing MOF shows excellent stability without fading after at least 2 months in air. Besides extending the photoabsorption to a wider wavelength range covering from 200 to 2,500 nm, the generation of persistent radical in IHEP‐15 also largely enhances its CO2 adsorption capacity by a factor of three due to the strong affinity between π orbital of the radical and the π system of CO2. These attributes endow IHEP‐15 with excellent visible/NIR light‐driven CO2 photoreduction activity, with CO production rates under visible and NIR irradiation of 570.3 and 209.3 µmol h−1 g−1, respectively. Notably, the latter is a record high for NIR‐induced CO production among all MOFs reported so far.

Tunable photo/thermochromic properties of Cd(ii)-viologen coordination polymers modulated by coordination modes for flexible imaging films and anti-counterfeiting

“…17 The core-level spectral peaks of N 1s at 398.46 eV and 401.18 eV can be ascribed to the coordinated N and the pyridine N atoms respectively. 18 Two peaks shifted to lower binding energies (398.34 eV and 401.06 eV) after irradiation, suggesting an increased electron density on the bipyridine N atoms (Fig. 5c).…”

Friends or Foes: Fundamental Principles of Th-Organic Scaffold Chemistry Using Zr-Analogs as a Guide

“…At the same time, the recent and rapidly growing interest in the development of fuel cycle reactors, radiological daughters for nuclear medicine, and efficient nuclear stockpile recycling serves as the driving force for translating the wealth of fundamental knowledge acquired for Zr-MOFs to thorium-based analogs. − Since the onset of research focusing on Th-based materials, Zr-frameworks have been considered to be the closest analogs due to the shared metal oxidation state (+4), high Lewis acidity, formation of strong coordination bonds to carboxylate-based organic linkers, and oxophilicity comparable to thorium. − However, in contrast to a plethora of publications (>3600) focusing on Zr-MOFs, only around 100 exist for their Th-based counterparts (Figure ). Moreover, less than 0.3% of these studies include any information on the reactivity of Th-based materials in a very narrow scope of reactions, targeting only six reaction classes. ,− Such disparity in the number of studies on zirconium-based versus thorium-based frameworks can be largely attributed to two main factors. For instance, the comprehensive fundamental understanding guiding the coordination chemistry of actinides is relatively underdeveloped in comparison with transition metals .…”

Thermally Induced Orderly Alignment of Porphyrin Photoactive Motifs in Metal–Organic Frameworks for Boosting Photocatalytic CO2 Reduction

“…Solar-driven conversion of carbon dioxide (CO 2 ) into energy-rich fuels or industrial feedstocks is a promising route to solve the energy crisis and reduce the concentration of CO 2 in the atmosphere. , Limited by the high stability of CO 2 , and the reduction process involves a complex multi-electron and proton transfer process, the development and application of various novel photocatalysts to improve the conversion and selectivity of CO 2 reduction is still a highly challenging and imminent issue. , With its characteristics of tailorable porosity and pore size, large specific surface area, high chemical stability, and easy functionalization, metal–organic frameworks (MOFs) have huge application prospects in the field of photocatalytic CO 2 reduction. − In the choice of ligands for the construction of MOFs, porphyrin and its derivative ligands have attracted ample attention due to its outstanding photosensitivity, and are often used in photocatalytic reactions. − Under the excitation of visible light, large π-conjugated porphyrin moiety can produce electron–hole pairs, which can be transferred to the substrate to achieve redox reactions after being successfully separated. , …”