查找使用阿拉丁产品的科研文献

Boosted photocatalytic hydrogen evolution of S-scheme N-doped CeO2-δ@ZnIn2S4 heterostructure photocatalyst

Shumail Farhan,Asif Hassan Raza,Songyu Yang,Zhixian Yu,Yan Wu

The advancement of highly effective heterojunction photocatalysts with improved charge separation and transfer has become a crucial scientific perspective for utilizing solar energy. In this study, we developed the S-scheme heterostructure by depositing N-doped CeO 2-δ (NC) nanoparticles onto two-dimensional ZnIn 2 S 4 (ZIS) nanosheets via hydrolysis strategy for significantly enhanced photocatalytic hydrogen evolution reaction. The optimal H 2 generation rate of ∼ 798 μmol g –1 h –1 was achieved for NC-3@ZIS under solar light irradiation, which is about 18 and 2 times higher than those of pristine CeO 2 (∼44 μmol g –1 h –1 ) and ZIS (∼358 μmol g –1 h –1 ), respectively. The photogenerated electrons from NC interact with the photogenerated holes of ZIS driven by an internal electric field, confirmed by In-situ KPFM, DFT calculation, and XPS results. According to EPR and photoelectrochemical measurements, NC-3@ZIS composite shows dramatically high separation efficiency of photogenerated charge carriers. This study provides a new approach for developing non-noble metal S-scheme heterojunctions with enhanced photocatalytic hydrogen evolution.

A facile approach to the preparation of S-doped porous carbons for CO2 adsorption

Hongmin Cui,Jianguo Xu,Nanfu Yan,Runhan Yan,Jinsong Shi

In the current work, we explored the direct synthesis of S-doped porous carbons employing cesium methanesulfonate as a novel bifunctional chemical activator. The obtained carbons showed high surface area (654–2264 m 2 /g) and high S content (6.56–15.13 wt%). Effects of activation temperature and cesium methanesulfonate amount on the carbons’ properties were also studied. The obtained carbons showed CO 2 uptake of 3.58–4.76 mmol/g at 0 °C and 1 bar. Effects of textural properties and S-doping on CO 2 adsorption performances were discussed.

Ag-S coordination strategy for high recovery driving stress in recyclable shape memory polymers

Zhongzheng Zhu,Siyu Liu,Junyi Yao,Qitan Zheng,Yutong Guo,Yujie Chen,Hezhou Liu,Hua Li

To address the issue of low strength and recovery stress in recyclable shape memory polymer (SMP) materials with dynamic covalent bonds in practical applications, we propose a method based on Ag-S coordination interactions to improve dynamic covalent bonds, thereby preparing recyclable SMP with high recovery stress and large recovery strain. The introduction of in situ reduced silver nanoparticles (AgNPs) in the SMP system play multiple roles, serving as additional physical crosslinking points at the microscale and coordinating with disulfide bonds in the system to construct a multi-level dynamic network structure. This endows the material with exceptional mechanical properties (tensile strength of 25.93 MPa and fracture strain of 1466.83 %) and recovery driving stress (5.59 MPa), while maintaining more than 99 % shape recovery and fixity rate. Furthermore, due to the outstanding photothermal performance of AgNPs, the composite material has acquired remote photothermal driving capabilities. The proposed Ag-S coordination enhancement offers a new approach for SMP materials that achieve both large actuation distance and high recovery stress, holding significant potential for applications in soft robotics and actuators.

Immobilization of cellulases on the reversibly soluble polymer Eudragit S-100 for cotton treatment

Yuanyuan Yu,Jiugang Yuan,Qiang Wang,Xuerong Fan,Ping Wang,Xuejiao Sun

Cellulases can penetrate into the fiber, causing tensile strength loss of the cellulosic fibers or fabrics. To minimize the tensile strength loss, we have immobilized cellulases on Eudragit S-100. The characteristics of covalent Eudragit cellulase were evaluated using gel filtration analysis and UV spectra. Gel filtration analysis revealed that the cellulases were covalently bound to the polymer. Covalent Eudragit cellulase was loaded with the enzyme of about 40% and had a relative activity about 80% at a Eudragit S-100 concentration of 15 g/L. When cellulase is bound to the polymer, the solubility profile becomes similar to the one of Eudragit. In addition, the effects of the enzyme on the cotton yarns and fabric using cellulases have been investigated. Native and immobilized cellulases caused improvements in whiteness and wrinkle recovery angle of the fabric in comparison to the control samples. The bending stiffness results show that native and immobilized cellulase treated cotton fabric has an improved softness than the control samples. It was found that using the immobilized cellulase reduced the weight and tensile strength, because the hydrolytic attack is only limited to the surfaces of cotton fibers.

Novel phosphorous–nitrogen containing poly(aryl ether ketone)s: synthesis, characterization, and thermal properties

Xuexia Xie,Zhou Wang,Kun Zhang,Jing Xu

Synthesis, characterization and thermal degradation of phosphorus–nitrogen containing poly(aryl ether ketone)s

Xuexia Xie,Zhou Wang,Kun Zhang,Jing Xu

A series of high-molecular-weight poly(aryl ether ketone)s with phosphorus and nitrogen on their side and main chains was synthesized by a nucleophilic substitution polycondensation of 6-(4-hydroxyphenyl)pyridazin-3(2H)-one (HPZ) with 1,1′-bis(4-hydroxyphenyl)-metheylene-bispheny-1-oxophosphine oxide (DOPO-PhOH) and 4, 4′-difluorobenzophenone (DFBP) at various molar ratios. The structures of the poly(aryl ether ketone)s were characterized by means of Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (1H NMR, 31P NMR) and elemental analysis. The influence of the nitrogen- and phosphorus-containing monomer ratio on their thermal stability was investigated by adjusting the proportion of the HPZ and DOPO–PhOH from 0:10 to 8:2. The polymers were readily soluble in polar organic solvents, such as N-methylpyrrolidone (NMP), N, N-dimethylacetamide (DMAc), N, N-dimethylformamide (DMF) and chloroform. Differential scanning calorimetry (DSC) demonstrated that these polymers have an amorphous morphology.

Polychlorinated biphenyls and their different level metabolites as inhibitors of glutathione S-transferase isoenzymes

Xingguo Tian,Erqun Song,Ruxian Pi,Xiaokang Zhu,Lichao Liu,Xiaoyan Ma,Hui Dong,Jing Liu,Yang Song

Research on the effects of polychlorinated biphenyl (PCB) toxicity tends to focus on commercial PCB congeners and parent PCBs themselves. However, studies have suggested that PCB metabolites may be more interesting than the parent compounds because of their high reactivity. As a key metabolic enzyme, glutathione S -transferases (GSTs) are responsible for detoxification by catalyzing the conjugation reaction of glutathione (GSH) to xenobiotics. Inhibition of GST activity indicates reduced detoxification ability. We investigated the inhibition of chicken liver GSTs by parent PCBs and their metabolites and observed dose-dependent inhibition in vitro ; inhibitory efficiency declined in the order GSH-conjugate   >   mono-hydroxyl ≈ quinone ≈ hydroquinone   >   parent PCB. Structure–inhibitory activity relationship studies indicated that with the inhibitory activity greatly increases with the number of GSH moieties or chlorine substituents on the quinone ring. However, no significant linear relationship was observed for chlorine pattern changes on the phenyl ring. The reversibility of PCB metabolite inhibition of GSTs is discussed. PCB mono-hydroxyl, hydroquinone and quinone forms showed irreversible inhibition of GSTs, which suggests a mechanism involving covalent binding to cysteine residues in the GST active site. PCB glutathionyl conjugates showed reversible GST inhibition, implying non-covalent binding. Furthermore, reactive oxygen species did not significantly affect GST activity.

Anatase TiO2/Defective UiO-66 porous octahedral S-scheme heterojunctions toward optimized photocatalytic performance

Mingtao Wang,Shijie Wang,Zhenzi Li,Xuepeng Wang,Liping Guo,Haixia Liu,Lijun Liao,Wei Zhou

Photocatalysis is an alternative for antibiotics removal from wastewater for the sustainable development of human society. However, applying photocatalysts for antibiotics (e.g., tetracycline) degradation under practical conditions is highly restricted by the low reaction efficiency due to the prompt charge recombination. Constructing porous heterojunctions is an efficient way to regulate the electron transfer path and accelerate charge migration efficiency. Herein, TiO 2 /defective UiO-66 porous octahedral S-scheme heterojunctions are successfully fabricated through an in-situ growth strategy. The strong interaction and charge migration behavior between TiO 2 and defective UiO-66 have been studied using X-ray photoelectron spectroscopy and electron paramagnetic resonance measurements. The photocatalytic removal efficiency of tetracycline is notably improved by forming TiO 2 /defective UiO-66 porous heterojunctions. The promoted photocatalytic performance can be ascribed to the strong interaction between TiO 2 and defective UiO-66, and the accelerated charge separation and transfer efficiency due to the formation of S-scheme heterojunctions, thus generating abundant reactive oxygen species, including O 2 − and OH. The optimized 38-TiO 2 /UiO-66-300 can eliminate 97.9 % of tetracycline in 60 min with a reaction constant rate of 0.0425 min −1 , which is approximately 4 and 10 times that of pristine TiO 2 and UiO-66-300, respectively. This work provides an alternate strategy for preparing highly active heterojunction photocatalysts for environmental applications.

Photocatalytic and fouling resistant MXene/3D-S-COF for efficient oil-water emulsion separation

Yanqing Qu,Yang Liu,Xiaoyu Du,Hongge Jia,Shuangping Xu,Mingyu Zhang,Bingyang Liu

Three-dimensional sphere covalent organic framework (3D-S-COF) membranes have received increasing attention in the field of oily wastewater and industrial organic matter due to their rich pore structure as well as having many exposed functional group sites. However, the synthesis of conventional imine COF through the Schiff base method, which suffers from the easy hydrolysis under organic solvent conditions. Herein, a novel super-wettable MXene/3D-S-COF composite membrane for oil–water emulsion separation was prepared by depositing MXene nanosheets on oxidized amide COF from the imine COF. The hydroxyl groups of the COF membrane not only improved the water permeability but also formed hydrogen bonds with the MXene layer, which enhanced the interaction and formed the high stability composite membrane. The porous 3D-S-COF and the zigzag MXene layer work synergistically to enable emulsion fluxes up to 240 L·m −2 h −1 bar −1 and the separation efficiency is more than 98 %. In addition, the residual mass of the composite membrane remained above 95 % after 10 days of immersion in various solvents, and it also has photocatalytic properties and good resistance to fouling. This study provides a brand new idea for the use of MXene/3D-S-COF based composite membrane for oil–water emulsion separation.

Study on the synthesis of bisphenol S by reactive dehydration in rotating packed bed

Ming-Tao He,Peng Li,Yin-Hao Wang,Lei Du,Song Huang,Hai-Kui Zou,Guang-Wen Chu,Bao-Chang Sun

In this work, the synthesis of bisphenol S (4,4′-BPS) using reactive dehydration in a rotating packed bed (RPB) was studied. Firstly, orthogonal experiments were adopted to investigate the effects of different operating conditions on the yield and content of 4,4′-BPS in a stirred tank reactor (STR), including the mesitylene/phenol molar ratio ( μ ), reflux dehydration time ( t ), and stirring speed ( n ), in order to optimize the operating conditions in STR. Based on the study in STR, the effects of operating conditions, including rotation speed ( N ), feeding rate ( q ), and cycle number ( τ ), on the yield and content of 4,4′-BPS in RPB combined with STR (RPB-STR) were further investigated to optimize the operating conditions. The results indicated that compared to STR, the yield and content of 4,4′-BPS increased by 22.1% and 7.52% under the optimal operating conditions in RPB-STR, respectively. This work provides a novel route for efficient synthesizing 4,4′-BPS.

Synthesis and cryogenic mechanical properties of degradable epoxy resins containing hexahydro-s-triazine structure

Tian Zhao,Yalin Zhao,Zhicong Miao,Tao Wang,Rongjin Huang,Laifeng Li

Epoxy resins are widely used in cryogenic applications due to their distinguished mechanical and electrical insulation properties. To avoid generating enormous amounts of waste that affect the environment and cause economic losses, covalent adaptable networks can be introduced into the epoxy structure to make the thermosetting network reversible. In this study, ester bond and hexahydro-s-triazine structure were adopted in epoxy structures. Two new degradable epoxy resins (HPBE and HPHE) with variances in the content of benzene rings were synthesized which were confirmed by FTIR and NMR. After curing, the thermal, mechanical, thermal conducting properties of the resulting materials were examined. The products exhibited tensile strength and flexural strength all above 120 MPa at 77 K, with glass transition temperature of 89.1 °C and 86.9 °C, respectively. Meanwhile, HPBE and HPHE demonstrated favorable thermal stability, with thermal conductivity comparable to that of the commonly used epoxy resin DGEBA. These resins could be degraded under mild conditions and demonstrated high hydrolysis efficiency (approximately 90 %). This investigation presented a viable method for the application of degradable thermosetting materials in cryogenic environments and the possibility for repairing of high-value equipment. 1

Tailored Phototherapy Agent by Infection Site In Situ Activated Against Methicillin-Resistant S. aureus

Lixia Guo,Yafei Tian,Liang Zhou,Shiyue Kang,Chengwu Zhang,Wen Liu,Haipeng Diao,Liheng Feng

Phototherapy, including photodynamic therapy (PDT) and photothermal therapy (PTT), is a promising treatment approach for multidrug resistant infections. PDT/PTT combination therapy can more efficiently eliminate pathogens without drug resistance. The key to improve the efficacy of photochemotherapy is the utilization efficiency of non-radiation energy of phototherapy agents. Herein, a facile phototherapy molecule (SCy-Le) with the enhancement of non-radiative energy transfer is designed by an acid stimulation under a single laser. Introduction of the protonated receptor into SCy-Le results in a distorted intramolecular charge in the infected acidic microenvironment, pH ≈ 5.5, which in turn, enhances light capture, reduces the singlet–triplet transition energies (Δ E S1–T1 ), promotes electron system crossing, enhances capacity of reactive oxygen species generation, and causes a significant increase in temperature by improving vibrational relaxation. SCy-Le shows more than 99% bacterial killing rate against both methicillin-resistant Staphylococcus aureus and its biofilms in vitro and causes bacteria-induced wound healing in mice. This work will provide a new perspective for the design of phototherapy agents, and the emerging photochemotherapy will be a promising approach to combat the problem of antibiotic resistance.