Generations Yi Ma,† Xiuli Wang,† Yushuai Jia,† Xiaobo Chen,‡ Hongxian Han,*,† and Can Li*,† †State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Dalian National Laboratory for Clean Energy, 457 Zhongshan Road, Dalian 116023, China ‡Department of Chemistry, College of Arts and Sciences, University of Missouri-Kansas City, 5100 Rockhill Road, Kansas City, Missouri 64110, United States

Titanium dioxide-based nanomaterials for photocatalytic fuel generations.

Covalent organic frameworks (COFs) are attractive candidates for advanced water-treatment membranes owing to their high porosity and well-organized channel structures. Herein, the continuous two-dimensional imine-linked COF-LZU1 membrane with a thickness of only 400 nm was prepared on alumina tubes by in situ solvothermal synthesis. The membrane shows excellent water permeance (ca. 760 L m-2  h-1  MPa-1 ) and favorable rejection rates exceeding 90 % for water-soluble dyes larger than 1.2 nm. The water permeance through the COF-LZU1 membrane is much higher than that of most membranes with similar rejection rates. Long-time operation demonstrates the outstanding stability of the COF-LZU1 membrane. As the membrane has no selectivity for hydrated salt ions (selectivity <12 %), it is also suitable for the purification of dye products from saline solutions. The excellent performance and the outstanding water stability render the COF-LZU1 membrane an interesting system for water purification.

High-Flux Membranes Based on the Covalent Organic Framework COF-LZU1 for Selective Dye Separation by Nanofiltration.

Covalent organic frameworks (COFs) have been proposed as alternative candidates for molecular sieving membranes due to their chemical stability. However, developing COF membranes with narrowed apertures close to the size of common gas molecules is a crucial task for selective gas separation. Herein, we demonstrate a new type of a two-dimensional layered-stacking COF–COF composite membrane in bilayer geometry synthesized on a porous support by successively regulating the growth of imine-based COF-LZU1 and azine-based ACOF-1 layers via a temperature-swing solvothermal approach. The resultant COF-LZU1–ACOF-1 bilayer membrane has much higher separation selectivity for H2/CO2, H2/N2, and H2/CH4 gas mixtures than the individual COF-LZU1 and ACOF-1 membranes due to the formation of interlaced pore networks, and the overall performance surpasses the Robeson upper bounds. The COF-LZU1–ACOF-1 bilayer membrane also shows high thermal and long-time stabilities.

Covalent Organic Framework–Covalent Organic Framework Bilayer Membranes for Highly Selective Gas Separation

Microporous polymers are covalently bound, entirely organic materials which possess very high surface areas. These materials have been intensively studied within recent years and various interesting properties and possible applications have been discovered and described. This review article starts with the question, what makes microporous polymers special and are there certain features which differentiate them from other microporous materials? Indeed, there are some special structural and functional features found in microporous polymers which make them really unique and merit further exploration. We focus here on microporous polymers which are solution-processable, can be produced as thin films on electrodes by oxidative polymerizations, are π-conjugated organic semiconductors, or which provide the possibility to introduce and exploit distinct functional groups in an otherwise non-functional highly porous environment. Emerging applications for these microporous polymers which make explicit use of these unique features are further presented.

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Trends and challenges for microporous polymers

Lewis-Acid-Catalyzed Interfacial Polymerization of Covalent Organic Framework Films

A direct synthesis of B-doped TiO2 and its photocatalytic performance on degradation of RhB

Although two-dimensional polymers (2DPs) and related materials are very attractive subjects for research because they are expected to function as ideal gas separation membrane materials, we need to...

Two-Dimensional and Related Polymers: Concepts, Synthesis, and their Potential Application as Separation Membrane Materials

Through loading of TiO2 on the surface of K6SiW11O39Co(II)(H2O)·xH2O (SiW11Co), a novel photoanode material has been created for dye-sensitized solar cells (DSSC). The absorbing band as well as photoelectricity response range of TiO2@SiW11Co is extended to the visible range. In addition, the absorption in the UV range is enhanced notably compared with P25 (raw TiO2). More importantly, the recombination of the TiO2 network is avoided. TiO2@SiW11Co is mixed with P25 powder (wt ∼1 : 1) to assemble dye-sensitized (N719) solar cells, which exhibit a short-circuit photocurrent density as high as 18.05 mA cm−2, which is 64% higher than blank samples under the standard AM1.5G global solar irradiation. In addition, the mechanisms for SiW11Co in DSSC are proposed.

Photocurrent enhanced dye-sensitized solar cells based on TiO2 loaded K6SiW11O39Co(II)(H2O)·xH2O photoanode materials.

Ethyl cellulose was grafted with ionic liquids in optimal yields (62.5–64.1%) and grafting degrees (5.93–7.90%) by the esterification of the hydroxyl groups in ethyl cellulose with the carboxyl groups in ionic liquids. In IR spectra of the ethyl cellulose derivatives exhibited C=O bond stretching vibration peaks at 1760 or 1740 cm−1, confirming the formation of the ester groups and furnishing the evidence of the successful grafting of ethyl cellulose with ionic liquids. The ethyl cellulose grafted with ionic liquids could be formed into membranes by using the casting solution method. The resulting membranes exhibited good membrane forming ability and mechanical properties. The EC grafted with ionic liquids-based membranes demonstrated PCO2/PCH4 separation factors of up to 18.8, whereas the PCO2/PCH4 separation factor of 9.0 was obtained for pure EC membrane (both for CO2/CH4 mixture gas). The membranes also demonstrated an excellent gas permeability coefficient PCO2, up to 199 Barrer, which was higher than pure EC (PCO2 = 46.8 Barrer). Therefore, it can be concluded that the ionic liquids with imidazole groups are immensely useful for improving the gas separation performances of EC membranes.

https://www.mdpi.com/2073-4360/11/11/1900/pdf

Liqun Ma

Papers

A direct synthesis of B-doped TiO2 and its photocatalytic performance on degradation of RhB

Two-Dimensional and Related Polymers: Concepts, Synthesis, and their Potential Application as Separation Membrane Materials

Photocurrent enhanced dye-sensitized solar cells based on TiO2 loaded K6SiW11O39Co(II)(H2O)·xH2O photoanode materials.

High Efficiency Gas Permeability Membranes from Ethyl Cellulose Grafted with Ionic Liquids.

Synthesis and oxygen permeation of novel polymers of phenylacetylenes having two hydroxyl groups via different lengths of spacers