Zwitterionic Covalent Organic Frameworks as Catalysts for Hierarchical Reduction of CO2 with Amine and Hydrosilane

2018 ◽  
Vol 10 (48) ◽  
pp. 41350-41358 ◽  
Author(s):  
Zhen-Jie Mu ◽  
Xuesong Ding ◽  
Zhi-Yan Chen ◽  
Bao-Hang Han
Synlett ◽  
2018 ◽  
Vol 29 (05) ◽  
pp. 548-555 ◽  
Author(s):  
Liang-Nian He ◽  
Xiao-Fang Liu ◽  
Xiao-Ya Li ◽  
Chang Qiao

Reductive functionalization of CO2 with amines and a reductant, which combines both reduction of CO2 and C–N bond formation in one pot to produce versatile chemicals and energy-storage materials such as formamides, aminals, and methylamines that are usually derived from petroleum feedstock, would be appealing and promising. Herein, we give a brief review on recent developments in the titled CO2 chemistry by employing transition-metal-free catalysis, which can be catalogued as below according to the diversified energy content of the products, that is formamides, aminals, and methylamines being consistent with 2-, 4-, and 6-electron reduction of CO2, respectively. Notably, hierarchical reduction of CO2 with amines to afford at least two products, for example, formamides and methylamines, could be realized with the same catalyst through tuning the hydrosilane type, reaction temperature, or CO2 pressure. Finally, the opportunities and challenges of the reductive functionalization of CO2 with amines are also highlighted.1 Introduction2 2-Electron Reduction of CO2 to Formamide3 6-Electron Reduction of CO2 to Methylamine4 4-Electron Reduction of CO2 to Aminal5 Hierarchical Reduction of CO2 with Amines6 Conclusion


2021 ◽  
Vol 50 ◽  
pp. 101590
Author(s):  
Qizhuang Zou ◽  
Yun Yi ◽  
Tianxiang Zhao ◽  
Fei Liu ◽  
Chao Kang ◽  
...  

Author(s):  
John Ozdemir ◽  
Imann Mosleh ◽  
Mojtaba Abolhassani ◽  
Lauren F. Greenlee ◽  
Robert R. Beitle ◽  
...  

Chem ◽  
2018 ◽  
Vol 4 (7) ◽  
pp. 1696-1709 ◽  
Author(s):  
Haoyu Liu ◽  
Jun Chu ◽  
Zhenglei Yin ◽  
Xin Cai ◽  
Lin Zhuang ◽  
...  

2021 ◽  
Author(s):  
Ruoyang Liu ◽  
Ke Tian Tan ◽  
Yifan Gong ◽  
Yongzhi Chen ◽  
Zhuoer Li ◽  
...  

Covalent organic frameworks offer a molecular platform for integrating organic units into periodically ordered yet extended 2D and 3D polymers to create topologically well-defined polygonal lattices and built-in discrete micropores and/or mesopores.


2018 ◽  
Author(s):  
Srimanta Pakhira ◽  
Jose Mendoza-Cortes

<div>Covalent organic frameworks (COFs) have emerged as an important class of nano-porous crystalline materials with many potential applications. They are intriguing platforms for the design of porous skeletons with special functionality at the molecular level. However, despite their extraordinary properties, it is difficult to control their electronic properties, thus hindering the potential implementation in electronic devices. A new form of nanoporous material, COFs intercalated with first row transition metal is proposed to address this fundamental drawback - the lack of electronic tunability. Using first-principles calculations, we have designed 31 new COF materials <i>in-silico</i> by intercalating all of the first row transition metals (TMs) with boroxine-linked and triazine-linked COFs: COF-TM-x (where TM=Sc-Zn and x=3-5). This is a significant addition considering that only 187 experimentally COFs structures has been reported and characterized so far. We have investigated their structure and electronic properties. Specifically, we predict that COF's band gap and density of states (DOSs) can be controlled by intercalating first row transition metal atoms (TM: Sc - Zn) and fine tuned by the concentration of TMs. We also found that the $d$-subshell electron density of the TMs plays the main role in determining the electronic properties of the COFs. Thus intercalated-COFs provide a new strategy to control the electronic properties of materials within a porous network. This work opens up new avenues for the design of TM-intercalated materials with promising future applications in nanoporous electronic devices, where a high surface area coupled with fine-tuned electronic properties are desired.</div>


Author(s):  
Austin M. Evans ◽  
Lucas R. Parent ◽  
Nathan C. Flanders ◽  
Ryan P. Bisbey ◽  
Edon Vitaku ◽  
...  

<div> <div> <div> <p>Polymerizing monomers into periodic two-dimensional (2D) networks provides structurally precise, atomically thin macromolecular sheets linked by robust, covalent bonds. These materials exhibit desirable mechanical, optoelectrotronic, and molecular transport properties derived from their designed structure and permanent porosity. 2D covalent organic frameworks (COFs) offer broad monomer scope, but are generally isolated as polycrystalline, insoluble powders with limited processability. Here we overcome this limitation by controlling 2D COF formation using a two- step procedure. In the first step, 2D COF nanoparticle seeds are prepared with approximate diameters of 30 nm. Next, monomers are slowly added to suppress new nucleation while promoting epitaxial growth on the existing seeds to sizes of several microns. The resulting COF nanoparticles are of exceptional and unprecedented quality, isolated as single crystalline materials with micron-scale domain sizes. These findings advance the controlled synthesis of 2D layered COFs and will enable a broad exploration of synthetic 2D polymer structures and properties. </p> </div> </div> </div>


2017 ◽  
Author(s):  
Austin M. Evans ◽  
Lucas R. Parent ◽  
Nathan C. Flanders ◽  
Ryan P. Bisbey ◽  
Edon Vitaku ◽  
...  

<div> <div> <div> <p>Polymerizing monomers into periodic two-dimensional (2D) networks provides structurally precise, atomically thin macromolecular sheets linked by robust, covalent bonds. These materials exhibit desirable mechanical, optoelectrotronic, and molecular transport properties derived from their designed structure and permanent porosity. 2D covalent organic frameworks (COFs) offer broad monomer scope, but are generally isolated as polycrystalline, insoluble powders with limited processability. Here we overcome this limitation by controlling 2D COF formation using a two- step procedure. In the first step, 2D COF nanoparticle seeds are prepared with approximate diameters of 30 nm. Next, monomers are slowly added to suppress new nucleation while promoting epitaxial growth on the existing seeds to sizes of several microns. The resulting COF nanoparticles are of exceptional and unprecedented quality, isolated as single crystalline materials with micron-scale domain sizes. These findings advance the controlled synthesis of 2D layered COFs and will enable a broad exploration of synthetic 2D polymer structures and properties. </p> </div> </div> </div>


2019 ◽  
Author(s):  
Sahithi Ananthaneni ◽  
Rees Rankin

<div>Electrochemical reduction of CO2 to useful chemical and fuels in an energy efficient way is currently an expensive and inefficient process. Recently, low-cost transition metal-carbides (TMCs) are proven to exhibit similar electronic structure similarities to Platinum-Group-Metal (PGM) catalysts and hence can be good substitutes for some important reduction reactions. In this work, we test graphenesupported WC (Tungsten Carbide) nanocluster as an electrocatalyst for the CO2 reduction reaction. Specifically, we perform DFT studies to understand various possible reaction mechanisms and determine the lowest thermodynamic energy landscape of CO2 reduction to various products such as CO, HCOOH, CH3OH, and CH4. This in-depth study of reaction energetics could lead to improvements and develop more efficient electrocatalysts for CO2 reduction.<br></div>


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