查找使用阿拉丁产品的科研文献

VO2 (D) submicron-spherical hierarchical structures as novel anode materials for aqueous lithium-ion batteries

Yining Ma,Dandan Zhu,Huaijuan Zhou,Yue Tang,Chenchen Hu,Xinyu Meng,Xiaodong Jin,Tongxiang Xu,Xun Cao

Vanadium dioxide (VO 2 ) material has been deemed as a potential anode candidate for aqueous lithium-ion batteries. Among its diversified polymorphs, the latest discovered VO 2 (D) receives the fewest reports on its application in energy storage. Herein, we successfully utilized a template-free solvothermal method to prepare VO 2 (D) submicron-spherical hierarchical structures, constructed with colibacillus-like nanorods . The VO 2 (D) submicron-spheres were applied as an active anode material into the aqueous lithium-ion battery, which exhibited suitable working potential. Furthermore, VO 2 (D)-based full cell with LiMn 2 O 4 as the cathode demonstrated high discharge capacity, good rate capability, and excellent cycling stability. The structural evolution, valence states of the VO 2 (D) electrode, and impedance variation of the full cell during cycling were investigated. The work reveals the potential of VO 2 (D) as a novel anode material for aqueous lithium-ion batteries.

Enhancement of the substrate specificity of D-amino acid oxidase based on tunnel-pocket engineering

Liuyu Wang,Heng Tang,Hongli Zhu,Yaping Xue,Yuguo Zheng

D -Amino acid oxidase (DAAO) selectively catalyzes the oxidative deamination of D -amino acids, making it one of the most promising routes for synthesizing optically pure L -amino acids, including L -phosphinothricin ( L -PPT), a chiral herbicide with significant market potential. However, the native DAAOs that have been reported have low activity against unnatural acid substrate D -PPT. Herein, we designed and screened a DAAO from Rhodotorula taiwanensis ( Rtw DAAO), and improved its catalytic potential toward D -PPT through protein engineering. A semirational design approach was employed to create a mutation library based on the tunnel-pocket engineering. After three rounds of iterative saturation mutagenesis, the optimal variant M 3rd -SHVG was obtained, exhibiting a >2000-fold increase in relative activity. The kinetic parameters showed that M 3rd -SHVG improved the substrate binding affinity and turnover number. This is the optimal parameter reported so far. Further, molecular dynamics simulation revealed that the M 3rd -SHVG reshapes the tunnel-pocket and corrects the direction of enzyme–substrate binding, allowing efficiently catalyze unnatural substrates. Our strategy demonstrates that the redesign of tunnel-pockets is effective in improving the activity and kinetic efficiency of DAAO, which provides a valuable reference for enzymatic catalysis. With the M 3rd -SHVG as biocatalyst, 500 mM D, L -PPT was completely converted and the yield reached 98%. The results laid the foundation for further industrial production.

Confined Ultrafine Pt in Porous Carbon Fibers and Their N-Enhanced Heavy d-π Effect

Yu-Xuan Xiao,Jie Ying,Jiang-Bo Chen,Yuan Dong,Xiong Yang,Ge Tian,Jinsong Wu,Christoph Janiak,Kenneth I. Ozoemena,Xiao-Yu Yang

The heavy d-π effect is an important theoretical model for strong Pt–C interaction, and its enhancement is critical to the high-performance design of Pt/C electrocatalysts. Common chemical N-doping to the carbon support can provide possibilities for enhanced electrocatalysis but most often leads to random interaction with Pt nanoparticles (Pt-NPs) and uncontrollable tuning of the heavy d-π effect. Directional confinement of Pt-NPs within N-doped carbon to directly enhance the heavy d-π effect is therefore mostly preferred but rarely reported. Herein, confined ultrafine Pt-NPs in N-doped porous carbon fibers (Pt@NDPCF) were obtained by a combination method involving electrospinning, carbonization, and directional replacement. Such a synthetic strategy leads to highly dispersed, ultrafine Pt-NPs in hierarchically porous carbon fibers and a strong directional interaction of Pt with pyridinic N, which significantly enhances the heavy d-π effect, greatly facilitating electron transfer and optimizing Pt 5d orbitals. Based on these advances, Pt@NDPCF exhibited outstanding activity and superior durability in the hydrogen evolution reaction (HER), with 24 mV lower overpotential at 10 mA cm–2 and a much smaller activity loss after 10,000 cycles of durability tests in comparison with a commercial Pt/C catalyst. This work sheds new lights on the design of high-performance Pt-based nanomaterials toward HER or other practical applications.

Open-Set Recognition for Unknown Organic Pollutants in Drinking Water With 3-D Fluorescence Spectroscopy

Hang Yin,Jie Yu,Fei Shi,Fangjia Xue,Jiegen Shi,Pingjie Huang,Dibo Hou

Synergistic d-p hybridized Co/W5N4 heterostructure catalyst for industrial alkaline water/seawater hydrogen evolution

Shipeng Geng,Liming Chen,Lianmei Kang,Ruchun Li,Haixin Chen,Luo Cheng,Dandan Cai,Yi Wang,Shuqin Song

Developing efficient and durable non-precious metal electrocatalysts with industrial current density is urgent for hydrogen evolution reaction from alkaline water/seawater but remains challenging. Here, a heterostructured Co/W 5 N 4 catalyst with porous structure is innovatively constructed. The theoretical calculations confirm the strong d-p hybridization between Co and N at the interface of Co/W 5 N 4 with the modulation of d‐band center of Co sites. The synergistic effect between Co and W 5 N 4 is disclosed that H 2 O can rapidly dissociate on the W sites to generate H* adsorbed at the Co sites for favorable H 2 production. Consequently, the Co/W 5 N 4 catalyst affords low overpotentials of 113 and 118 mV to drive current density of 100 mA cm −2 in alkaline water/seawater electrolytes, respectively, which are even superior to those of commercial Pt/C. More importantly, it can also present outstanding HER stability at large current density of 500 mA cm −2 for over two weeks (350 h) in alkaline water/seawater electrocatalysis.

Novel D–π-A type near-infrared fluorescent probes for the detection of Aβ40 aggregates

Guanglei Lv,Yunze Xu,Jiajia Yang,Wenhui Li,Chunxia Li,Anyang Sun

Aberrant accumulation of Amyloid-β (Aβ) peptide is closely related to Alzheimer's disease. Thus, it is important to develop featured probes for the specific detection of Aβ species. Herein, we designed and synthesized a novel near-infrared fluorescent probe SDPY based on the D–π-A architecture for the detection of Aβ aggregates. The probe SDPY displayed higher affinity for Aβ40 aggregates over Aβ42 aggregates in solution (Kd = 164 nM vs. 2.1 μM). In addition, SDPY showed excellent anti-interference against a wide range of other substances. Furthermore, SDPY was capable of labeling Aβ40 aggregates better than Aβ42 aggregates in the brain sections of AD transgenic mouse models.

Acid-modulated porous AgI/D-MIL-53(Fe) composites for the removal of antibiotic contaminant

Jiang Danni,Zhou Yu,Wang Ping,Huang Chao,Zhu Jian,Liu Zhiming

In the MOFs-based composites, the co-catalyst nanoparticles loads tend to agglomerate. In the self-assembly process of MOFs-based composites, the use of acid modulators solved the accumulation of AgI nanoparticles cocatalyst. The active sites of carboxyl groups and mesoporous structure brought by acid modulator provide more loading sites for AgI nanoparticles. The novel AgI/D-MIL-53(Fe) showed good adsorption and photocatalytic performance in the process of removing tetracycline pollutants. Compared to the degradation efficiency of the MIL-53(Fe) with 50.8%, it of AgI/MIL-53(Fe) increased to 85.1% and which further increased to 96.2% by AgI/D-MIL-53(Fe) based on the HCl modulator. On the one hand, it is beneficial for the mesoporous D-MIL-53(Fe) modulated by HCl modulator to disperse the AgI nanoparticles co-catalyst. On the other hand, AgI nanoparticles, as a photosensitive agent, adsorb visible light to generate photogenerated electrons and holes, and electrons rapidly transferred to the heterojunction bridge Ag 0 and then captured by the holes from the D-MIL-53(Fe). The construction of AgI/D-MIL-53(Fe) Z-scheme heterojunction provided favorable conditions for the rapid separation and photogenerated electrons and holes. Finally, ·O 2 − , ·OH and h + as the main active free radicals were driving forces. This study provided more possibilities and opportunities for the construction of mesoporous MOFs-based composites.

Fluorination effects of A-D-A small molecule donors based benzotriazole for organic solar cells

Huihui Gu,Yuancheng Qin,Weili Dai,Dan Zhou,Yu Xie

To explore the effect of fluorine atom on photophysical properties, in this work, we synthesized three new small molecules (SMs) with acceptor-donor-acceptor (A-D-A) configuration, SM-0F , SM-2F and SM-4F , where 4,8-bis(octyloxy)benzo[1,2-b:4,5-b']dithiophene ( BDT ) as the electron-donating and benzo[d][1,2,3]triazole ( BTA ) or fluorinated BTA as electron-withdrawing. The three small molecules exhibit good solubility and thermal stability as well as strong absorption. The fluorination of BTA unit made SM-2F and SM-4F possess a relatively lower the highest occupied molecular orbital (HOMO) and higher electron mobility in comparison with SM-0 F. We treated the three small molecules as donor and PC 71 BM as the acceptor to manufacture small molecule organic solar cells. After introduction of F, the power conversion efficiency (PCE) is improved. Among them, device based on SM-2F gave the best device performance with a PCE of 3.94% with J sc of 11. 37 mA/cm 2 , V oc of 0.76 V, fill factor ( FF ) of 0.45. These studies show that the incorporation of fluorine atom is an effective method to increase the efficiency of organic solar cells.

Carbon dots as fluorescent nanoprobe for the determination of N-acetyl-β-d-glucosaminidase activity

Jimei Ma,Heng Zhang,Fangfang Peng,Xiaoqing Yang,Zi-Long Li,Linhao Sun,Hong Jiang

Carbon dots (CDs) were synthesized from p -aminophenol and ethylenediamine via one-step under mild condition and used as a sensitive fluorescent nanoprobe for the activity determination of N -acetyl-β- d -glucosaminidase (NAG). In this assay, p -nitrophenol was in situ produced from p -nitrophenyl-β-D- N -acetyl-glucosaminide, which was exclusively hydrolyzed by NAG. The UV absorption peak of p -nitrophenol (maximum at 400 nm) overlapped the excitation peak of CDs with maximum wavelength at 415 nm, which caused the fluorescence decline of CDs based on inner filter effect. The activity of NAG was determined by the fluorescence changes. The assay is highly sensitive to NAG with a low detection limit of 0.75 U L −1  (K = 3) and showed a good linear relationship in the range from 1 to 45 U L −1 . This CDs nanoprobe was successfully applied for the determination of NAG activity in human serum and urine samples.

One-dimensional controllable crosslinked polymers grafted with N-methyl-D-glucamine for effective boron adsorption

Jingjing Kang,Yakun Tang,Shasha Gao,Lang Liu

In this research, a series of one-dimensional controllable crosslinked polymers with the different mass ratios of 4-vinylbenzychloride (VBC) and divinyl benzene (DVB) was prepared via cationic polymerization, and the polymers were grafted with the functional group N-methyl-D-glucamine (NMDG) for boron removal. The optimum polymeric mass ratio and a series of boron adsorption performances were studied. The maximum adsorption capacity was 18.15 mg g−1, of which 94% was retained after 4 cycles. Meanwhile, different pH values had negligible effect on the boron adsorption capacity, which was favorable for the removal of boron from its aqueous solution in a wide pH window. In addition, a magnetic adsorbent was prepared by the combination of Fe3O4 nanoparticles and the polymer, which provided an effective way to collect and recover adsorbents from their aqueous solutions.

Sensitive detection and imaging of endogenous peroxynitrite using a benzo[d]thiazole derived cyanine probe

Tianxin Hou,Kui Zhang,Xiaoxuan Kang,Xueling Guo,Libo Du,Xinfeng Chen,Long Yu,Ji Yue,Hongwei Ge,Yang Liu,Abdullah M. Asiri,Khalid A. Alamry,Huan Yu,Suhua Wang

Peroxynitrite is a short-lived endogenous reactive species and plays important roles in many physiological and pathological processes. In this work, we synthesized a near-infrared probe based on the structure of benzothiazole derived cyanine for determination of peroxynitrite (ONOO - ). The designed probe specifically reacted with ONOO - through oxidative cleavage of conjugated C˭C double bonds and generating the non-fluorescent product. Meanwhile, the characteristic absorption of the probe at 630 nm greatly decreased after reaction with ONOO - , accompanied by drastic color change from bright blue to green yellow, which exhibited a distinct visual feature. It was demonstrated that the probe could be used to measure ONOO - in a dose-response manner and had a detection limit lower as 26 nM. Furthermore, the probe Cy-SN was applied for the imaging of endogenous ONOO - in living cells by confocal microscopy , which showed good cell permeability and low cytotoxicity. Successful application of probe for exogenous colorimetric detection and endogenous fluorescence imaging of ONOO - is suggesting its great potential applications in biological analysis.

Chiral ligand exchange capillary electrochromatography with dual ligands for enantioseparation of D,L-amino acids

Wenya Feng,Juan Qiao,Dan Li,Li Qi

Utilizing block copolymers as coatings, a protocol of chiral ligand exchange capillary electrochromatography (CLE-CEC) protocol was designed and developed with dual ligands for D,L-amino acids enantioseparation. Four block copolymers including poly maleic anhydride- co -styrene- co -N-methacryloyl- L -histidine methyl ester [P(MAn-St-MAH)], poly maleic anhydride- co -styrene- co -N-methacryloyl- L -lysine methyl ester [P(MAn-St-MAL)], poly maleic anhydride- co -styrene- co -N-methacryloyl- L -phenylalanine methyl ester [P(MAn-St-MAP)] and poly maleic anhydride- co -styrene- co -N-methacryloyl- L -threonine methyl ester [P(MAn-St-MAT)] were synthesized by reversible addition fragmentation chain transfer polymerization reaction. Key factors affecting the enantioresolution were optimized, including the concentration of Zn (II) central ion, pH value of buffer solution and monomers of the block copolymers. The enantioresolution of the proposed CLE-CEC system could be enhanced dramatically by employing P(MAn-St-MAH) as the immobilized chiral ligand and by coordinating the synergistic effect of free ligand in buffer solution. The principle of improved enantioresolution of the CLE-CEC system with dual ligands was discussed. Well enantioseparation was successfully realized with 7 pairs of D,L-amino acids enantiomers baseline separation and 5 pairs part separation. For quantitative analysis of D, L -alanine, a good linearity was established in the range of 9.4 μM to 1.5 mM (r 2 = 0.997) with the limits of detection (LODs) 3.7 μM of D -alanine, 2.0 μM for L -alanine, and limits of quantification (LOQs) 9.0 μM for D -alanine and 6.0 μM for L -alanine. The peak area and migration time reproducibility (n = 6) were 4.1% and 3.5% for D -alanine, 3.7% and 3.1% for L -alanine. Further, the enzyme kinetics study of alanine aminotransferase was investigated with the constructed CLE-CEC system.