Facile and scalable synthesis of functionalized hierarchical porous polymers for efficient uranium adsorption.

Efficient uranium capture from wastewater holds great importance for the environmental remediation and sustainable development of nuclear energy, but it is a tremendous challenge. Herein, a facile and scalable approach is reported to fabricate functionalized hierarchical porous polymers (PPN-3) decorated with high density of phosphate groups for uranium adsorption. The as-constructed hierarchical porous structure could allow rapid diffusion of uranyl ions, while abundant phosphate groups that serve as adsorption sites could provide the high affinity for uranyl. Consequently, PPN-3 shows a high uranium adsorption uptake of 923.06 mg g-1 and reaches adsorption equilibrium within simply 10 min in uranium-spiked aqueous solution. Moreover, PPN-3 affords selective adsorption of uranyl over multiple metal ions and possesses a rapid and high removal rate of U(VI) in real water systems. Furthermore, this study offers direct polymerization strategy for the cost-effective fabrication of phosphate-functionalized porous organic polymers, which may provide promising application potential for uranium extraction.

Development of High-Performance Iron-Based Phosphate Cathodes toward Practical Na-Ion Batteries.

Iron-based phosphate cathode of Na4Fe3(PO4)2(P2O7) has been regarded as a low-cost and structurally stable cathode material for Na-ion batteries (NIBs). However, their practical application is greatly hindered by the insufficient electrochemical performance and limited energy density. Here, we report a new iron-based phosphate cathode of Na4.5Fe3.5(PO4)2.5(P2O7) with the intergrown heterostructure of the maricite-type NaFePO4 and orthorhombic Na4Fe3(PO4)2(P2O7) phases at a mole ratio of 0.5:1. Benefited from the increased composition ratio and the spontaneous activation of the maricite-type NaFePO4 phase, the as-prepared Na4.5Fe3.5(PO4)2.5(P2O7) composites deliver a reversible capacity over 130 mA h g-1 and energy density close to 400 W h kg-1, which is far beyond that of the single-phase Na4Fe3(PO4)2(P2O7) cathode (∼120 mA h g-1 and ∼350 W h kg-1). Moreover, the kg-level products from the scale-up synthesis demonstrate a stable cycling performance over 2000 times at 3 C in pouch cells. We believe that our findings could show the way forward the practical application of the iron-based phosphate cathodes for NIBs.

Production of Optically Pure (S)-3-Hydroxy-γ-butyrolactone from d-Xylose Using Engineered Escherichia coli.

Biocatalysis has advantages in asymmetric synthesis due to the excellent stereoselectivity of enzymes. The present study established an efficient biosynthesis pathway for optically pure (S)-3-hydroxy-γ-butyrolactone [(S)-3HγBL] production using engineered Escherichia coli. We mimicked the 1,2,4-butanetriol biosynthesis route and constructed a five-step pathway consisting of d-xylose dehydrogenase, d-xylonolactonase, d-xylonate dehydratase, 2-keto acid decarboxylase, and aldehyde dehydrogenase. The engineered strain harboring the five enzymes could convert d-xylose to 3HγBL with glycerol as the carbon source. Stereochemical analysis by chiral GC proved that the microbially synthesized product was a single isomer, and the enantiomeric excess (ee) value reached 99.3%. (S)-3HγBL production was further enhanced by disrupting the branched pathways responsible for d-xylose uptake and intermediate reduction. Fed-batch fermentation of the best engineered strain showed the highest (S)-3HγBL titer of 3.5 g/L. The volumetric productivity and molar yield of (S)-3HγBL on d-xylose reached 50.6 mg/(L·h) and 52.1%, respectively. The final fermentation product was extracted, purified, and confirmed by NMR. This process utilized renewable d-xylose as the feedstock and offered an alternative approach for the production of the valuable chemical.

Cation-Intercalated Lamellar MoS2 Adsorbent Enables Highly Selective Capture of Cesium.

Highly selective capture of cesium (Cs+) from complex aqueous solutions has become increasingly important owing to its (133Cs) indispensable role in some cutting-edge technologies and the environmental mobility of radioactive nuclide (137Cs) from nuclear wastewater. Herein, we report the development of cation-intercalated lamellar MoS2 as an effective Cs+ adsorbent with the advantages of facile synthesis and highly tunable layer spacing. Two types of cations, including Na+ and NH4+, were employed for the intercalations between adjacent layers of MoS2. The results demonstrated that the adsorption capacity of the NH4+-intercalated material (M-NH4+, 134 mg/g) for Cs+ clearly outperformed the others due to higher loading percentages of cations and larger layer spacing. The cesium partition coefficients for M-NH4+ in the presence of 100-fold competing ions all exceed 1 × 103 mL/g. A simulated complex aqueous solution containing 15.37 mg/L Cs+ and highly excess of competing ions Li+, Na+, K+, Mg2+, and Ca2+ (20-306 times higher) was introduced to prove the practical application potential using our best-performing M-NH4+, showing a good to excellent partition ability of Cs+ among other cations, especially for Cs/K and Cs/Na with separation factors of 58 and 212, respectively. The adsorption and selectivity mechanisms were clearly elucidated using various advanced techniques, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. These results revealed that the good selectivity for Cs+ can be ascribed to the differences in Lewis acidities, hydration energy, cation sizes, and in particular, the divergence of coordination modes which was successfully achieved after tuning the layer distance via the cation intercalation strategy. In addition, the material has fast kinetics (<30 min), wide range of pH tolerance (4-10), and good reusability. Overall, our studies point out that the tunable lamellar MoS2-based materials are promising adsorbents for Cs+ capture and separation.

Structural elucidation and targeted valorization of untractable lignin from pre-hydrolysis liquor of xylose production via a simple and robust separation approach.

Effective separation of lignin macromolecules from the xylose pre-hydrolysates (XPH) during the xylose production, thus optimizing the separation and purification process of xylose, is of great significance for reducing the production costs, achieving the high value-added utilization of lignin and increasing the industrial revenue. In this study, a simple and robust method (pH adjustment) for the separation of lignin from XPH was proposed and systematically compared with the conventional acid-promoted lignin precipitation method. The results showed that the lignin removal ratio (up to 60.34 %) of this simple method was higher than that of the conventional method, and the proposed method eliminated the necessity of heating and specialized equipment, which greatly reduced the separation cost. Meanwhile, this simple method does not destroy the components in XPH (especially xylose), ensuring the yield of the target product. On the other hand, the obtained lignin was nano-scale with less condensed structures, which also possessed small molecular weights with narrow distribution, excellent antioxidant activity (8-14 times higher than commercial antioxidants) and UV protection properties. In conclusion, the proposed simple separation method could effectively separate lignin from XPH at low cost, and the obtained lignin had potential commercial applications, which would further enhance the overall profitability of industrial production.

Bounds on the Probability of Undetected Error for q-Ary Codes.

We study the probability of an undetected error for general q-ary codes. We give upper and lower bounds on this quantity, by the Linear Programming and the Polynomial methods, as a function of the length, size, and minimum distance. Sharper bounds are obtained in the important special case of binary Hamming codes. Finally, several examples are given to illustrate the results of this paper.

Regulating the Spin State of Metal and Metal Carbide Heterojunctions for Efficient Oxygen Evolution.

Developing high-performance electrocatalysts for oxygen evolution reaction (OER) is of importance for improving the overall efficiency of water splitting. Herein, the CoFe/(CoxFe1-x)3Mo3C heterojunction is purposely designed as an OER catalyst, which displays a low overpotential of 293 mV for affording a current density of 10 mA cm-2 and a small Tafel slope of 48 mV/dec. Various characterization results demonstrate that the significant work-function difference between CoFe and (CoxFe1-x)3Mo3C can induce interfacial charge redistribution, which results in the formation of Co and Fe sites with a high-spin state, thus stimulating the surface phase reconstruction of CoFe/(CoxFe1-x)3Mo3C to corresponding active oxyhydroxide. Meanwhile, the electrochemical leaching of Mo ions from the initial structure can contribute to the formation of defective sites, further benefiting OH- adsorption and surface oxidation. Moreover, the remaining CoFe can accelerate electron migration during the electrocatalytic process. This study presents new insights into constructing efficient OER electrocatalysts with an optimized spin-state configuration via interfacial engineering.

Electrodialysis Deacidification of Acid Hydrolysate in Hemicellulose Saccharification Process: Membrane Fouling Identification and Mechanisms.

Acid saccharification of hemicelluloses offers promising pathways to sustainably diversify the revenue of the lignocellulose biorefinery industry. Electrodialysis to separate inorganic acids from acid hydrolysate in the hemicellulose saccharification process could realize the recovery of sulfuric acid, and significantly reduced the chemical consumption than the traditional ion exchange resins method. In this work, the deacidification of corncob acid hydrolysate was conducted by a homemade electrodialysis apparatus. The results showed that: (1) more than 99% of acid can be removed through the electrodialysis process; (2) A non-negligible membrane fouling occurred during the electrodialysis process, which aggravated with the repeated batch running The final global system resistance rose from 15.8 Ω (1st batch) to 43.9 Ω (10th batch), and the treatment ending time was delayed from 120 min (1st batch) to 162 min (10th batch); (4) About 90% of protein, 70% of ferulate acid, and 80% of p-coumarate acid precipitated from the corncob acid hydrolysate during the electrodialysis process. The zeta potential of corncob acid hydrolysate changed from a positive value to a negative value, and an isoelectric point around pH 2.3 was reached. HSQC, FTTR, and GPC, along with SEM and EDS analysis, revealed that the fouling layers mostly consisted of hydrolysates of protein and lignin. The result of HSQC indicated that the membrane foulant may exist in the form of lignin-carbohydrate complexes, as the lignin component of the membrane foulant is in the form of p-coumarate and ferulate. From the result of FTIR, a strong chemical bonding, such as a covalent linkage, existed between the lignin and protein in the membrane foulant. Throughout the electrodialysis process, the increased pH decreased the stability of colloidal particles, including lignin and proteins. Destabilized colloidal particles started to self-aggregate and form deposits on the anion exchange membrane's surface. Over time, these deposits covered the entire membrane surface and the spaces between the membranes. Eventually, they attached to the surface of the cation exchange membrane. In the end, a suggestion to control and minimize membrane fouling in this process was discussed: lower pH as a process endpoint and a post-treatment method.

Surface Engineering Stabilizes Rhombohedral Sodium Manganese Hexacyanoferrates for High-Energy Na-Ion Batteries.

The rhombohedral sodium manganese hexacyanoferrate (MnHCF) only containing cheap Fe and Mn metals was regarded as a scalable, low-cost, and high-energy cathode material for Na-ion batteries. However, the unexpected Jahn-teller effect and significant phase transformation would cause Mn dissolution and anisotropic volume change, thus leading to capacity loss and structural instability. Here we report a simple room-temperature route to construct a magical Cox B skin on the surface of MnHCF. Benefited from the complete coverage and the buffer effect of Cox B layer, the modified MnHCF cathode exhibits suppressed Mn dissolution and reduced intergranular cracks inside particles, thereby demonstrating thousands-cycle level cycling lifespan. By comparing two key parameters in the real energy world, i.e., cost per kilowatt-hours and cost per cycle-life, our developed Cox B coated MnHCF cathode demonstrates more competitive application potential than the benchmarking LiFePO4 for Li-ion batteries.

Preferential Extraction of Lithium from Spent Cathodes and the Regeneration of Layered Oxides for Li/Na-Ion Batteries.

The preferentially selective extraction of Li+ from spent layered transition metal oxide (LiMO2, M = Ni, Co, Mn, etc.) cathodes has attracted extensive interest based on economic and recycling efficiency requirements. Presently, the efficient recycling of spent LiMO2 is still challenging due to the element loss in multistep processes. Here, we developed a facile strategy to selectively extract Li+ from LiMO2 scraps with stoichiometric H2SO4. The proton exchange reaction could be driven using temperature, accompanied by the generation of soluble Li2SO4 and MOOH precipitates. The extraction mechanism includes a two-stage evolution, including dissolution and ion exchange. As a result, the extraction rate of Li+ is over 98.5% and that of M ions is less than 0.1% for S-NCM. For S-LCO, the selective extraction result is even better. Finally, Li2CO3 products with a purity of 99.68% can be prepared from the Li+-rich leachate, demonstrating lithium recovery efficiencies as high as 95 and 96.3% from NCM scraps and S-LCO scraps, respectively. In the available cases, this work also represents the highest recycling efficiency of lithium, which can be attributed to the high leaching rate and selectivity of Li+, and even demonstrates the lowest reagent cost. The regenerated LiNi0.5Co0.24Mn0.26O2 and Na1.01Li0.001Ni0.38Co0.18Mn0.44O2 cathodes also deliver a decent electrochemical performance for Li-ion batteries (LIBs) and Na-ion batteries (NIBs), respectively. Our current work offers a facile, closed-loop, and scalable strategy for recycling spent LIB cathodes based on the preferentially selective extraction of Li+, which is superior to the other leaching technology in terms of its cost and recycling yield.

Regulated Synthesis of α-NaVOPO4 with an Enhanced Conductive Network as a High-Performance Cathode for Aqueous Na-Ion Batteries.

The 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 α-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.

O3-NaFe(1/3-x)Ni1/3Mn1/3AlxO2 Cathodes with Improved Air Stability for Na-Ion Batteries.

Na-ion batteries (NIBs) have been considered as potential candidates for large-scale energy storage, where O3-type Na-based layered oxide cathodes have attracted great attention due to their high capacity and low cost. However, O3-NaxTMO2 materials still suffer from insufficient air stability, which could lead to deteriorative electrochemical properties and thus hinder their practical application. In this work, a series of Al-doped O3-NaFe(1/3-x)Ni1/3Mn1/3AlxO2 cathodes prepared by a co-precipitation method were investigated to enhance their electrochemical performance and air stability through stabilizing their structural and interface chemical properties. The Al-doped O3-NaFe(1/3-0.01)Ni1/3Mn1/3Al0.01O2 (NFNMA0.01) cathode delivers a comparable capacity of 138 mAh g-1 and keeps a capacity retention of 85.88% after 50 cycles at 0.2 C, while the undoped O3-NaFe1/3Ni1/3Mn1/3O2 (NFNM) can only keep a capacity retention of 71.02%, although with an initial capacity of 141 mAh g-1 at 0.2 C. For the air stability, the capacity decay rates are 58.87 and 5.07% for the undoped NFNM and Al-doped NFNMA0.01 after the air exposure for 30 days, respectively. The greatly decaying electrochemical performance could be due to the formation of carbonates during air exposure, which can be efficiently suppressed by Al doping. The doped Al3+ has been confirmed to be inserted into the NFNM crystal lattice, inducing the reduced values of lattice parameters a and c due to the smaller ionic radius of Al3+ (53.5 pm) vs Fe3+ (55.0 pm). This study demonstrates that Al doping plays an important role in the air stability and cycling stability for layered cathode materials, which offers an efficient strategy to optimize the material design for their practical application in NIBs.

Rapid mechanochemical synthesis of polyanionic cathode with improved electrochemical performance for Na-ion batteries.

Na-ion batteries have been considered promising candidates for stationary energy storage. However, their wide application is hindered by issues such as high cost and insufficient electrochemical performance, particularly for cathode materials. Here, we report a solvent-free mechanochemical protocol for the in-situ fabrication of sodium vanadium fluorophosphates. Benefiting from the nano-crystallization features and extra Na-storage sites achieved in the synthesis process, the as-prepared carbon-coated Na3(VOPO4)2F nanocomposite exhibits capacity of 142 mAh g-1 at 0.1C, higher than its theoretical capacity (130 mAh g-1). Moreover, a scaled synthesis with 2 kg of product was conducted and 26650-prototype cells were demonstrated to proof the electrochemical performance. We expect our findings to mark an important step in the industrial application of sodium vanadium fluorophosphates for Na-ion batteries.

Donor-Acceptor Couples of Metal and Metal Oxides with Enriched Ni3+ Active Sites for Oxygen Evolution.

Exploiting precious-metal-free and high-activity oxygen evolution reaction (OER) electrocatalysts has been in great demands toward many energy storage and conversion processes, for example, carbon dioxide reduction, metal-air batteries, and water splitting. In this study, the simple solid-state method is employed for coupling Ni (electron donors) with lower-Fermi-level MoO2 or WOx (electron acceptors) into donor-acceptor ensembles with well-designed interfaces as robust electrocatalysts for OER. The resulting Ni/MoO2 and Ni/WOx electrocatalysts exhibit smaller overpotentials of 287 and 333 mV at 10 mA cm-2 as well as smaller Tafel slopes of 51 and 65 mV/dec, respectively, with respect to the single Ni, MoO2, WOx, and even the benchmark RuO2 in 1 M KOH. Specially, on account of a higher Fermi level of Ni in comparison with MoO2 and WOx, their strong electronic interaction results in directional interfacial electron transfer and increases the hole density over Ni, dramatically enriching the population of high-valence Ni3+ active sites and decreasing the Fermi level of Ni. The existence of Ni3+ can strengthen the chemisorption of OH-, and the downshift of the Ni Fermi level can significantly expedite migration of electrons toward the surface of catalysts during OER, thus synergistically boosting the OER catalytic performance. Furthermore, the inner Ni/MoO2 and Ni/WOx heterostructures and the electrochemically induced surface layers of oxides/hydroxides collectively boost the OER kinetics. This study highlights the importance of designing highly efficient OER electrocatalysts with high-valence active species (Ni3+) and better matched energy levels induced by the work function difference through interfacial engineering.

Selective recovery of Li and FePO4 from spent LiFePO4 cathode scraps by organic acids and the properties of the regenerated LiFePO4.

To recycle the sharply growing spent lithium-ion batteries and alleviate concerns over shortages of resources, particularly Li, is still an urgent issue. In this work, an organic acids based leaching approach at room temperature is proposed to recover Li and FePO4 from spent LiFePO4 cathode powder. The coexistent metal ions, Cu and Al, have also been investigated. Citrus fruit juices, rich in organic acids, such as citric acid and malic acid, have been used as leaching agents in this work. Among lemon, orange and apple, lemon juice shows the best leaching effect based on its suitable pH of the reaction system. Under the optimized conditions, the leaching rates of Li, Cu and Al can reach up to 94.83%, 96.92% and 47.24%, while Fe and P remain as low as 4.05% and 0.84%, respectively. Li2CO3 and FePO4 can be recovered from the leachate and the leaching residue, respectively. The recovered FePO4 was used to prepare new cathode material LiFePO4. The crystalline carbon, present in the spent LiFePO4 cathode scraps, has a significant effect on the electrochemical performances of the regenerated LiFePO4. The regenerated LiFePO4 cathode material delivered a comparable discharge capacity of 155.3 mAh g-1 at 0.1C and rate capacity to the fresh LiFePO4. For the cycling stability, it displays capacity retention of 98.30% over 100 cycles at 1 C with a fading rate of 0.017% per cycle. The proposed organic acids-based recycling strategy is much benign for recycling the spent LiFePO4 cathode materials.

An Aminotransferase from Enhydrobacter aerosaccus to Obtain Optically Pure ß-Phenylalanine.

An aminotransferase ω-TAEn was identified from Enhydrobacter aerosaccus. The ω-TAEn was successfully expressed in Escherichia coli and the obtained enzyme showed activity toward ß-phenylalanine (ß-phe) at optimal conditions. For optically pure (R)-ß-phe, 50% yield was observed by kinetic resolution of racemic amino with pyruvate as the amino acceptor. To obtain (S)-ß-phe, the lipase/ω-TAEn catalytic system was adopted. The ω-TAEn showed strict stereoselectivity to the amino donor. The formation of (S)-ß-phe was observed using 3-aminobutyric acid as the amino donor, and (S)-ß-phe was obtained by asymmetric synthesis with a yield of 82%.

Correction to: Enhancement of the catalytic activity of Isopentenyl diphosphate isomerase (IDI) from Saccharomyces cerevisiae through random and site-directed mutagenesis.

The authors of this article [1] wish to draw the readers' attention to their closely related paper, published in RSC Advances [2] which should have been cited in this article. The authors regret that there is unattributed overlap in text describing the construction of the plasmid coding for the biosynthetic pathway because of the commonly used research strategies between this article [1] and similar work presented in RSC Advances, although this does not affect the main scientific conclusion in this study.

Metabolic engineering of Escherichia coli for the utilization of ethanol.

BACKGROUND: The fuel ethanol industry has made tremendous progress in the last decades. Ethanol can be obtained by fermentation using a variety of biomass materials as the feedstocks. However, few studies have been conducted on ethanol utilization by microorganisms. The price of petroleum-derived ethanol, easily made by the hydrolysis of ethylene, is even lower than that of bioethanol. If ethanol can be metabolized by microorganisms to produce value-added chemicals, it will open a new door for the utilization of inexpensive ethanol resources. RESULTS: We constructed an engineered Escherichia coli strain which could utilize ethanol as the sole carbon source. The alcohol dehydrogenase and aldehyde dehydrogenase from Aspergillus nidulans was introduced into E. coli and the recombinant strain acquired the ability to grow on ethanol. Cell growth continued when ethanol was supplied after glucose starvation and 2.24 g L-1 of ethanol was further consumed during the shake-flasks fermentation process. Then ethanol was further used for the production of mevalonic acid by heterologously expressing its biosynthetic pathway. Deuterium-labeled ethanol-D6 as the feedstock confirmed that mevalonic acid was synthesized from ethanol. CONCLUSIONS: This study demonstrated the possibility of using ethanol as the carbon source by engineered E. coli strains. It can serve as the basis for the construction of more robust strains in the future though the catabolic capacity of ethanol should be further improved.

Small molecule-mediated self-assembly behaviors of Pluronic block copolymers in aqueous solution: impact of hydrogen bonding on the morphological transition of Pluronic micelles.

The influence of hydrogen bonding on the self-assembly behaviors of Pluronic P123 micelles is experimentally and theoretically investigated by introducing three small molecules, i.e. propyl benzoate (PB), propyl paraben (PP) and propyl gallate (PG) into the aqueous solution. It is discovered that the number of phenolic hydroxyl groups and concentration of the tested small molecules exhibit a profound impact on the micellar morphology. Although all the small molecules increase the size and polydispersity of Pluronic micelles in a concentration-dependent manner, the micellar morphologies induced by them vary considerably as demonstrated by DLS and cryo-TEM measurement. PB, without phenolic hydroxyl, cannot bring about the morphological change of P123 micelles, while PP induces a series of morphological transitions from spheres to long worm-like micelles and then to unilamellar vesicles by increasing the PP content. Upon increasing the number of phenolic hydroxyls in small molecules, i.e. PG, the fusion of the intermicellar core takes place, resulting in the formation of large micelles and micellar clusters. A qualitative study by NMR reveals that the different locations of small molecules within the micelles are attributed to the balance of hydrogen bonding and hydrophobic interaction between small molecules and copolymers. In addition, molecular dynamics simulations (MDS) are performed to further confirm the experimental results and provide quantitative information on intermolecular interaction strength. It is supposed that the mechanism of micellar morphological transition mediated by small molecules is ascribed to the hydrogen bonding interactions with varying strengths between the PEO blocks and their phenolic hydroxyls, which governs their locations in micelles, affecting the free energies from different regions of micelles, and consequently leads to the varying micellar morphologies. This study deepens our understanding of the role of hydrgen bonding in the self-assembly behaviors of Pluronic micelles and provides an alternative strategy for manipulating the nanostructure of Pluronic micelles.

One-Pot Synthesis of 5-Hydroxymethylfurfural from Glucose by Brønsted Acid-Free Bifunctional Porous Coordination Polymers in Water.

Efficient synthesis of 5-hydroxymethylfurfural (HMF) using glucose (Glc) as a starting material represents an important process in biomass transformation. In this study, novel bifunctional porous coordination polymer (PCP) catalysts [PCP(Cr)-NH2-x (CH3) x ; x = 0, 1, or 2] containing Lewis acidic and Lewis basic sites have been synthesized and utilized as solid-phase catalysts for HMF synthesis starting from a Glc-in-water system. PCP(Cr)-NH2 was found as the optimal catalyst, with an HMF yield of 65.9% and Glc conversion of 99.9% in a water/tetrahydrofuran (THF) system. Compared with PCP(Cr), amino groups in PCP(Cr)-NH2 catalysts play a vital role in Glc isomerization and subsequent dehydration-cyclization process to obtain the highly selective and effective fructose-to-HMF conversion. High yield and chemoselectivity are ascribed to concurrent extraction of HMF into the THF layer just upon its formation in water. The mechanism of Lewis acid-base synergistic catalysis was deduced by means of infrared spectroscopy, and catalysts could be reused after simple washing procedure with high reproducibility.