Institutional Repository of Institute of Process Engineering, CAS (IPE-IR）
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Regulated Synthesis of α-NaVOPO4with an Enhanced Conductive Network as a High-Performance Cathode for Aqueous Na-Ion Batteries
No full textThe low-cost and profusion of sodium reserves make Na-ion batteries (NIBs) a potential candidate to lithium-ion batteries for grid-scale energy storage applications. NaVOPO4 has been recognized as one of the most promising cathodes for high-energy NIBs, owing to their high theoretical capacity and energy density. However, their further application is hindered by the multiphase transition and conductivity confinement. Herein, we proposed a feasible, one-step hydrothermal synthesis to regulate the synthesis of 伪-NaVOPO4 with controlled morphologies. The electrochemical properties of the NaVOPO4 electrode can be significantly enhanced taking Ketjen black (KB) as the optimized conductive carbon. Besides, combining with the nanocrystallization and construction of the conductive framework via high-energy ball milling, taking KB as the conductive carbon, the as-prepared NaVOPO4/5%KB exhibits superior Na-storage performance (140.2 mA h g-1 at 0.1 C and a capacity retention of 84.8% over 1000 cycles at 10 C) to the original NaVOPO4 (128.5 mA h g-1 at 0.1 C and a capacity retention of 83.1% over 1000 cycles at 10 C). Moreover, the aqueous full cell with NaTi2(PO4)3 as the anode delivers a capacity of 114.7 mA h g-1 at 0.2 C (141 W h kg-1 energy density) and 80.6% capacity retention over 300 cycles at 5 C. The excellent electrochemical performance can be attributed to the nanosized structural and enhanced interfacial effect, which could be rewarding to construct electron transportation tunnels, thus speeding up the Na+-diffusion kinetics. The modified strategy provides an efficient approach to intensify the electrochemical performance, which exhibits potential application of the NaVOPO4 cathode for NIBs.
A one-step preparation of superhydrophobic stainless steel mesh and application in raffinate cleaning technology as a coalescer for contaminated organic-water separation
No full textImproving raffinate oil-water separation efficiency and simplifying the production process of coalescing material are both in great demand but remain difficult. In this study, a superhydrophobic stainless steel surface was created using a simple one-step electrodeposition process in an electrolyte solution comprising nickel chloride (NiCl2路6H2O), stearic acid, and ethanol. The surface shape, chemical content, and superhydrophobic property were studied using a scanning electron microscope (SEM), Fourier-transform infrared (FT-IR) spectrometer, energy dispersive spectroscopy (EDS), and contact angle measurement. The cotton-like microstructure, comprised of crystals of Ni metal and Ni(CH3(CH2)16COO)2, demonstrated outstanding acid and alkaline resistance with a maximum surface contact angle of 166.8掳. The oil-water separation performance of raffinate was tested in a mixer-settler, and the separation efficiency ranged from 75% to 80% in a P507 + Kerosene/water system, based on Chemical Oxygen Demand (COD) indicating its potential applicability in the solvent extraction process. A high-speed camera was also used to observe the coalescing behavior of oil droplets in water. 漏 202
Structural Engineering of FDT toward Promising Spiro-Typed Hole-Transporting Materials: Promoting the Hole Transport and Stabilizing the HOMO Levels
No full textDesign of a new spiro-typed core structure is one of the most important approaches for developing highly efficient hole-transporting materials (HTMs). In this work, the strategies of modifying with O/S heteroatoms and introducing a helical 蟺-linker are evaluated based on the typical FDT molecule. Theoretical calculations show that all the highest occupied molecular orbitals (HOMOs) and the lowest unoccupied molecular orbitals (LUMOs) of the studied HTMs are matched well with the energy band structure of perovskite, and the HOMO levels display a gradually negative-shifted trend from the FDT to SM30, which means that the favorable hole extraction and the easy interfacial energy regulation can be anticipated. Compared to the light absorption of the FDT, the absorption spectra of new tailored HTMs are slightly red-shifted. More importantly, our results indicate that introducing a helical 蟺-linker and modification with heteroatoms in the spiro-typed core can be the effective methods to promote the hole transport ability of HTMs. Both the methods can effectually heighten the crystal stacking and intermolecular electronic couplings and further facilitate the hole transport of HTMs. Furthermore, the large Stokes shifts and the better solubility are also displayed for the newly tailored HTMs. In sum, this work provides useful insights for the design of highly efficient HTMs, and three new spiro-typed HTMs are proposed. 漏 2022 American Chemical Society. All rights reserved
Catalytic deoxygenation of carboxyl compounds in the hydrothermal liquefaction crude bio-oil via in-situ hydrogen supply by CuO-CeO2/纬-Al2O3 catalyst
No full textHydrothermal liquefaction (HTL) has drawn great attention as a potential method to produce bio-oil from biomass waste. However, bio-crude from HTL shows undesired high-oxygen content and needs further deoxygenation upgrading. Herein, stearic acids as a model carboxylic compounds in HTL bio-crude was employed to investigate catalytic deoxygenation performance. Results showed that (CuO)10-CeO2/纬-Al2O3 had the most superior catalytic deoxygenation performance for the stearic acids. The maximum stearic acid conversion rate (96.36%) and total hydrocarbon yield (88.79%) were obtained at 300掳C, 12h, ratio of stearic acid to water 1:4. The main catalytic deoxygenation pathways were proposed: carbon monoxide generation (decarbonylation) 鈥?in-situ hydrogen generation (water鈥揼as shift) 鈥?short-chain fatty acid generation (hydrogenolysis) 鈥?n-alkanes generation (decarboxylation, hydrodeoxygenation and hydrogenation). DFT calculation elucidated that CuO-CeO2 reduced the activation energy from 24.8kcalmol鈭? (vacuum) to 15.0kcalmol鈭? (catalytic). Thus, deoxygenation via CuO-CeO2/纬-Al2O3 would be an effective method for upgrading HTL bio-crude. 漏 2022 Elsevier Lt
Charged Nanochannels in Covalent Organic Framework Membranes Enabling Efficient Ion Exclusion
No full textControllable ion transport through nanochannels is crucial for biological and artificial membrane systems. Covalent organic frameworks (COFs) with regular and tunable nanochannels are emerging as an ideal material platform to develop synthetic membranes for ion transport. However, ion exclusion by COF membranes remains challenging because most COF materials have large-sized nanochannels leading to nonselective transport of small ions. Here we develop ionic COF membranes (iCOFMs) to control ion transport through charged framework nanochannels, the interior surfaces of which are covered with arrayed sulfonate groups to render superior charge density. The overlap of an electrical double layer in charged nanochannels blocks the entry of co-ions, narrows their passageways, and concomitantly restrains the permeation of counterions via the charge balance. These highly charged large-sized nanochannels within the iCOFM enable ion exclusion while maintaining intrinsically high water permeability. Our results reveal possibilities for controllable ion transport based on COF membranes for water purification, ionic separation, sensing, and energy conversion. 漏 2022 American Chemical Society. All rights reserved
Finely tuning the microporosity in dual thermally crosslinked polyimide membranes for plasticization resistance gas separations
No full textThermally induced chemical crosslinking has attracted substantial attention for fabricating plasticization resistant membranes due to the facile structure tunability that enables the construction of robust and well-defined architecture for gas separation. In this study, we report a new series of dual thermally crosslinkable polyimides derived from 4,4鈥?diamino-2,2鈥?biphenyldicarboxylic acid (DCB) containing two carboxyl groups, and a systematic investigation of the thermal treatment above and below Tg demonstrated the decarboxylation-induced crosslinking. The dual thermally crosslinked membranes were insoluble in common organic solvents and maintained excellent mechanical properties. Due to the evolution of CO2 and collapse of chain segments during thermal treatment, the crosslinked membranes exhibited hierarchical microcavity size distribution featuring ultra-micropore size in the range of 2.0鈥?.0 脜 and micropore size in the range of 6.5鈥?0.0 脜. Gas transport properties of the crosslinked membranes were feasibly tuned through the chemical compositions and thermal treatment procedures. For instance, the CO2 permeability of crosslinked 6FDA-DAM0.7-TFMB0.1-DCB0.2 increased almost three-fold with only a slight decrease in CO2/CH4 selectivity. The crosslinked membranes also demonstrated superior plasticization resistance with mixed-gas feed pressure up to 40 bar and excellent low-temperature gas separation performance at 鈭?0 掳C, making them attractive for aggressive gas separations. 漏 2022 Elsevier B.V
Chondrogenic preconditioning of mesenchymal stem/stromal cells within a magnetic scaffold for osteochondral repair
No full textAbstract
Stem cell therapy using mesenchymal stem/stromal cells (MSCs) represents a novel approach to treating severe diseases, including osteoarthritis. However, the therapeutic benefit of MSCs is highly dependent on their differentiation state, which can be regulated by many factors. Herein, three-dimensional (3D) magnetic scaffolds were successfully fabricated by incorporating magnetic nanoparticles (MNPs) into electrospun gelatin nanofibers. When positioned near a rotating magnet (f = 0.5 Hz), the magnetic scaffolds with the embedded MSCs were driven upward/downward in the culture container, which induced mechanical stimulation to MSCs due to spatial confinement and fluid flow. The extracellular matrix-mimicking scaffold and the alternating magnetic field significantly enhanced chondrogenesis instead of osteogenesis. Furthermore, the fiber topography could be tuned with different compositions of the coating layer on MNPs, and the topography had a significant impact on MSC differentiation. Selective up-regulation of chondrogenesis-related genes (COL2A1 and ACAN) was found for the magnetic scaffolds with citric acid-coated MNPs (CAG). In contrast, osteogenesis-related genes (RUNX2 and SPARC) were selectively and significantly up-regulated for the magnetic scaffolds with polyvinylpyrrolidone-coated MNPs. Prior to implantation in vivo, chondrogenic preconditioning of MSCs within the CAG scaffolds under a dynamic magnetic field resulted in superior osteochondral repair. Hence, the magnetic scaffolds together with an in-house rotating magnet device could be a novel platform to initiate multiple stimuli on stem cell differentiation for effective repair of osteochondral defects
