Site-specific anisotropic assembly of amorphous mesoporous subunits on crystalline metal–organic framework
Nature Communications， Pub Date : 2023-03-03 , 

DOI: 10.1038/s41467-023-36832-2
Minchao Liu, Cheng Shang, Tiancong Zhao, Hongyue Yu, Yufang Kou, Zirui Lv, Mengmeng Hou, Fan Zhang, Qiaowei Li, Dongyuan Zhao, Xiaomin Li

As an important branch of anisotropic nanohybrids (ANHs) with multiple surfaces and functions, the porous ANHs (p-ANHs) have attracted extensive attentions because of the unique characteristics of high surface area, tunable pore structures and controllable framework compositions, etc. However, due to the large surface-chemistry and lattice mismatches between the crystalline and amorphous porous nanomaterials, the site-specific anisotropic assembly of amorphous subunits on crystalline host is challenging. Here, we report a selective occupation strategy to achieve site-specific anisotropic growth of amorphous mesoporous subunits on crystalline metal–organic framework (MOF). The amorphous polydopamine (mPDA) building blocks can be controllably grown on the {100} (type 1) or {110} (type 2) facets of crystalline ZIF-8 to form the binary super-structured p-ANHs. Based on the secondary epitaxial growth of tertiary MOF building blocks on type 1 and 2 nanostructures, the ternary p-ANHs with controllable compositions and architectures are also rationally synthesized (type 3 and 4). These intricate and unprecedented superstructures provide a good platform for the construction of nanocomposites with multiple functionalities and understanding of the structure-property-function relationships.

https://www.nature.com/articles/s41467-023-36832-2

Sulfonic-Pendent Vinylene-Linked Covalent Organic Frameworks Enabling Benchmark Potential in Advanced Energy

Advanced Science， Pub Date : 2023-03-01 , 

DOI: 10.1002/advs.202300408
Ying Xu , Zhiwu Yu, Qingyun Zhang, Feng Luo

Both proton exchange membrane fuel cells and uranium-based nuclear techniques represent two green and advanced energies. However, both of them still face some intractable scientific and industrial problems. For the former, established proton-conduction materials always suffer one or another defect such as low proton conductivity, high activation energy, bad durability, or just small-scale product; while for the later, there still lacks available adsorbent to selectively recover of UO22+ from concentrated nitric acid (>1 M) during the spent fuel reprocessing due to the deactivation of the adsorption site or the decomposition of adsorbent under such rigorous conditions. It is found that the above two issues can be well solved by the construction of sulfonic-pendent vinylene-linked covalent organic frameworks (COFs), since these COFs contain abundant sulfonic units for both intrinsic proton conduction and UO22+ capture through strong coordination fixation and vinylene linkage that enhances the stability up to 12 M nitric acid (one of the best materials surviving in 12 M HNO3).

https://onlinelibrary.wiley.com/doi/full/10.1002/advs.202300408

Metal-organic frameworks for C2H2/CO2 separation: Recent development
Coordination Chemistry Reviews， Pub Date : 2023-03-01 ,

DOI: 10.1016/j.ccr.2023.215093
Xiaokang Wang, Hongyan Liu, Yue Li, Xinlei Yang, Fei Gao, Xiaoqing Wang, Zixi Kang, Weidong Fan, Daofeng Sun

The high-efficiency separation of C2H2/CO2 has important research significance and industrial value. The currently reported metal–organic framework (MOF) adsorbents for the separation of C2H2/CO2 are generally based on unsaturated metal sites, strong hydrogen bonds or strong electrostatic interaction sites, which suffer from difficulties in combining selectivity and capacity. Significant efforts have been devoted to solving this trade-off effect, and considerable achievements have been made. Herein, we review the research progress of MOFs for C2H2/CO2 separation in the past few years according to the properties of the material structure, and prospect the future research directions.

https://www.sciencedirect.com/science/article/pii/S0010854523000826

Designing covalent organic frameworks with Co-O4 atomic sites for efficient CO2 photoreduction
Nature Communications， Pub Date : 2023-02-28 , 

DOI: 10.1038/s41467-023-36779-4
Qian Zhang, Shuaiqi Gao, Yingying Guo, Huiyong Wang, Jishi Wei, Xiaofang Su, Hucheng Zhang, Zhimin Liu, Jianji Wang

Cobalt coordinated covalent organic frameworks have attracted increasing interest in the field of CO2 photoreduction to CO, owing to their high electron affinity and predesigned structures. However, achieving high conversion efficiency is challenging since most Co related coordination environments facilitate fast recombination of photogenerated electron-hole pairs. Here, we design two kinds of Co-COF catalysts with oxygen coordinated Co atoms and find that after tuning of coordination environment, the reported Co framework catalyst with Co-O4 sites exhibits a high CO production rate of 18000 µmol g−1 h−1 with selectivity as high as 95.7% under visible light irradiation. From in/ex-situ spectral characterizations and theoretical calculations, it is revealed that the predesigned Co-O4 sites significantly facilitate the carrier migration in framework matrixes and inhibit the recombination of photogenerated electron-hole pairs in the photocatalytic process. This work opens a way for the design of high-performance catalysts for CO2 photoreduction.

https://www.nature.com/articles/s41467-023-36779-4

Tuning excited state electronic structure and charge transport in covalent organic frameworks for enhanced photocatalytic performance
Nature Communications，Pub Date : 2023-02-27 ,

DOI: 10.1038/s41467-023-36710-x
Zhongshan Chen, Jingyi Wang, Mengjie Hao, Yinghui Xie, Xiaolu Liu, Hui Yang 1 , Geoffrey I N Waterhouse, Xiangke Wang, Shengqian Ma

Covalent organic frameworks (COFs) represent an emerging class of organic photocatalysts. However, their complicated structures lead to indeterminacy about photocatalytic active sites and reaction mechanisms. Herein, we use reticular chemistry to construct a family of isoreticular crystalline hydrazide-based COF photocatalysts, with the optoelectronic properties and local pore characteristics of the COFs modulated using different linkers. The excited state electronic distribution and transport pathways in the COFs are probed using a host of experimental methods and theoretical calculations at a molecular level. One of our developed COFs (denoted as COF-4) exhibits a remarkable excited state electron utilization efficiency and charge transfer properties, achieving a record-high photocatalytic uranium extraction performance of ~6.84 mg/g/day in natural seawater among all techniques reported so far. This study brings a new understanding about the operation of COF-based photocatalysts, guiding the design of improved COF photocatalysts for many applications.

https://www.nature.com/articles/s41467-023-36710-x

Construction of Covalent Organic Frameworks via a Visible-Light-Activated Photocatalytic Multicomponent Reaction
Journal of the American Chemical Society，Pub Date : 2023-02-27 ,

DOI: 10.1021/jacs.2c13541
Guang-Bo Wang, Yan-Jing Wang, Jing-Lan Kan, Ke-Hui Xie, Hai-Peng Xu, Fei Zhao, Miao-Can Wang, Yan Geng*, and Yu-Bin Dong*

Multicomponent reactions (MCRs), as a powerful one-pot combinatorial synthesis tool, have been recently applied to the synthesis of covalent organic frameworks (COFs). Compared with the thermally driven MCRs, the photocatalytic MCR-based COF synthesis has not yet been investigated. Herein, we first report the construction of COFs by a photocatalytic multicomponent reaction. Upon visible-light irradiation, a series of COFs with excellent crystallinity, stability, and permanent porosity are successfully synthesized via photoredox-catalyzed multicomponent Petasis reaction under ambient conditions. Additionally, the obtained Cy-N3-COF exhibits excellent photoactivity and recyclability for the visible-light-driven oxidative hydroxylation of arylboronic acids. The concept of photocatalytic multicomponent polymerization not only enriches the methodology for COF synthesis but also opens a new avenue for the construction of COFs that might not be possible with the existing synthetic methods based on thermally driven MCRs.

https://pubs.acs.org/doi/abs/10.1021/jacs.2c13541

https://www.pnas.org/doi/10.1073/pnas.22066191