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Efficient and inherently safe NH3 storage and separation are of significant importance for the chemical industry. Herein, we proposed zwitterionic COF as a porous host to disperse LiCl for highly efficient NH3 storage and separation with record adsorption capacity. The equivalently cationic and anionic groups in the channels of zwitterionic COF could act as two separated sites to facilitate the dispersion of LiCl, hence the optimal composite exhibits a high capture capacity of 44.98 mmol/g at 25 °C and 1 bar, far exceeding other existing porous materials. Notably, the adsorption capacity is completely reversible and the efficient separation of NH3 from NH3/CO2/N2 mixture is achieved through breakthrough experiments. DFT calculation combined with XPS and 7Li NMR experimental results give insight into the interaction between zwitterionic COF and LiCl. This work extends possibilities for the development of efficient adsorbents for NH3 storage and separation. [ABSTRACT FROM AUTHOR]

Xe is an ideal anesthetic gas, but it has not been widely used in practice due to its high cost and low output. Closed‐circuit Xe recovery and recycling is an economically viable method to ensure adequate supply in medical use. Herein, we design an innovative way to recover Xe by using a stable fluorinated metal‐organic framework (MOF) NbOFFIVE‐1‐Ni to eliminate CO2 from moist exhaled anesthetic gases. Unlike other Xe recovery MOFs with low Xe/CO2 selectivity (less than 10), NbOFFIVE‐1‐Ni could achieve absolute molecular sieve separation of CO2/Xe with excellent CO2 selectivity (825). Mixed‐gas breakthrough experiments assert the potential of NbOFFIVE‐1‐Ni as a molecular sieve adsorbent for the effective and energy‐efficient removal of carbon dioxide with 99.16 % Xe recovery. Absolute CO2/Xe separation in NbOFFIVE‐1‐Ni makes closed‐circuit Xe recovery and recycling can be easily realized, demonstrating the potential of NbOFFIVE‐1‐Ni for important anesthetic gas regeneration under ambient conditions. [ABSTRACT FROM AUTHOR]

• Humidity sensor based on sulfonate-based COF is fabricated. • 2D sulfonate-based COF possesses superior water adsorption capacity (∼396 mg/g). • COF's 1D pore can provide continuous proton/ions conducting channel. Sensing material is crucial to the performance of humidity sensors. Porous material is widely used for humidity sensing but suffers from the narrow detecting range and slow response speed. Herein, the porous TpBDSA-Na COF with a large pore size (∼1.7 nm) and high density of hydrophilic active sites is used as sensing material for humidity detector. The superior adsorption capacity of water molecules (∼396 mg/g) in TpBDSA-Na COF makes the humidity detector exhibit fast response speed (18/9 s), small hysteresis (∼3% RH) and long-term stability (∼20 days) in 11%–95% RH range. Moreover, the sensing mechanism of TpBDSA-Na sensor is also discussed in detail. This research indicates the 2D COF with a hydrophilic channel can be used as a promising material for humidity sensing. [ABSTRACT FROM AUTHOR]

• Ionic covalent organic framework (COF) named TpPa-SO 3 Na was successfully fabricated into humidity sensor for the first time. • The sensor presents good linearity, rapid response characteristic, narrow hysteresis and excellent long-term stability. • The TpPa-SO 3 Na with self-provided ion carriers plays an important role in improving the conductivity in periodic pore structure. With the increasing requirement of precise humidity control in agriculture, industry, and scientific experiments, the humidity sensors based on porous materials such as metal-organic framework (MOF) have aroused much attention because of their high porosity and tunable structure. However, the reported MOFs exhibit narrow detecting range and long response time due to the absence of ion carriers in porous framework. In this paper, an ionic covalent organic framework (COF) named TpPa-SO 3 Na was synthesized, and its humidity sensing performance was investigated for the first time. TpPa-SO 3 Na with -SO 3 Na groups possesses a water adsorption capacity of 411 cm3 g−1, which is confirmed by water adsorption-desorption measurement. The sensor based on TpPa-SO 3 Na exhibits good impedance-RH linearity, rapid response characteristic (∼6 s) and narrow hysteresis (∼3% RH) in the 11–95 % RH. Moreover, the ionic COF sensing material presents good repeatability. These results strongly suggest ionic COFs are a class of promising candidates for humidity sensing applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • PAF-XJTUs with medium micropore pore size (0.85–1.01 nm) and high specific surface area (1419.02–2024.62 m2/g) were prepared. • PAF-XJTUs with strong carbon–carbon linkage have hydrofluoric acid resistance. • PAF-XJTUs show effective separation performances under elevated pressure (10 bar). The public concern about sulfur hexafluoride (SF 6) emission has driven the exploration of related removal processes via adsorptive separation technology. Based on task-specific porous materials, the capture of SF 6 achieves lower energy consumption and less carbon footprint. Herein, four HF resistant porous aromatic frameworks (PAF-XJTU-1 to PAF-XJTU-4) with robust C C linkage were prepared for the separation of SF 6 in semiconductor etching exhaust. Single-component gas adsorption and IAST selectivity confirmed the separation performance of the four PAFs materials under elevated pressure (10 bar). Moreover, DFT studies revealed the nonnegligible SF 6 intermolecular interaction in PAFs at elevated pressure. Under the dynamic scenario, breakthrough experiments proved the effective capture of SF 6 in PAF-XJTUs. [ABSTRACT FROM AUTHOR]

Abstract: A series of nitrogen-doped nanoporous carbon (NNC) materials were prepared by directly carbonizing sol–gel composites containing aluminum phosphate, citric acid and hexamethylene tetramine (HMT). The structure and surface properties of these NNC materials were characterized by means of elemental analysis, N2 adsorption, X-ray powder diffraction (XRD), scanning electron microscope (SEM), high-resolution transmission electron microscopy (TEM), Fourier transform infrared spectra (FT-IR), and X-ray photoelectron spectra (XPS). Besides possessing various oxygen-containing groups, these NNC materials also contain different types of nitrogen-containing groups, including pyridinic-N, pyrrolic-N and quaternary-N groups. The resulting NNC materials are highly active and selective heterogeneous catalysts for the transesterification of dimethyl oxalate (DMO) with phenol to produce methyl phenyl oxalate (MPO) and diphenyl oxalate (DPO), and can be easily recycled by simple filtration. The presence of suitable surface basic sites should be mainly responsible for the excellent catalytic performance of NNC materials in the transesterification reaction. [Copyright &y& Elsevier]

Abstract: Well-dispersed carbon-supported MgO catalysts were prepared using a kind of porous carbon (NC-2) as support and magnesium nitrate solution as MgO precursor by a simple wet impregnation technique. Various characterization techniques, including XRD, N2 sorption, DRIFT, XPS and TPD, were carried out to investigate their physical–chemical properties, the states of MgO species and the interaction between MgO and NC-2 materials. The catalytic properties of MgO/NC-2 catalysts were investigated in the liquid-phase transesterification of dimethyl carbonate (DMC) with diethyl carbonate (DEC). Compared with other kinds of carbon-supported MgO catalysts, MgO/NC-2 shows remarkably higher activity for the formation of ethyl methyl carbonate (EMC). Moreover, the NC-2 supported catalyst possesses very high stability against leaching of active species under test reaction conditions, indicating the truly heterogeneous nature of this catalyst. The presence of relatively rich oxygen-containing surface groups on the NC-2 carbon support should be in favor of the high dispersion of MgO particles, thus being beneficial to the fabrication of active and stable heterogeneous catalysts for the transesterificaiton reaction. [Copyright &y& Elsevier]

Abstract: A series of porous carbon (NC) materials were prepared by using in situ-formed aluminophosphate framework as template, and citric acid and sucrose as carbon precursors. The structure and surface chemistry properties of these carbon materials were studied by N2 adsorption, XRD, DRIFT, and XPS measurements. The catalytic properties of these NC materials were investigated in the selective oxidation of benzyl alcohol with air as oxidant source. Compared with other carbon materials, such as active carbon, mesoporous CMK-3, and carbon molecular sieves, NC materials exhibited much higher catalytic activity with nearly 100% selectivity to benzaldehyde. The presence of abundant surface quinone groups, which originates from the special preparation process of NC material, is likely responsible for the high catalytic property of these porous carbon materials. [Copyright &y& Elsevier]

Abstract: The synthesis of mesoporous SBA-15 coated with the preformed precursor of microporous aluminophosphate (AlPO) has been reported. The physicochemical properties of the coated samples were investigated by using XRD, FT-IR, N2-adsorption, ICP, 29Si MAS NMR, NH3-TPD and CO2-TPD. The characterization results suggest that the nanometer-scaled zeolite units are present on the wall surface of SBA-15, thus bringing the weak acid–base characteristics to the resulting mesoporous materials, and that the acid–base properties of these materials can be modified by the aging treatment in glycol. Moreover, vapor-phase O-methylation of catechol with methanol has been studied on these coated samples as catalysts. It is found that the coated sample bearing suitable weak acid–base sites exhibits the relatively high activity and selectivity to guaiacol. [Copyright &y& Elsevier]