查找使用阿拉丁产品的科研文献

One-pot synthesis of branched alternating copolymers P(St-alt-MAn) via free radical polymerization in the presence of chain transfer monomer

Liu Jingcheng,Xiong Xiaomei,Liu Ren,Jiang Jinqiang,Liu Xiaoya

Novel branched alternating copolymers poly(styrene- alt -maleic anhydride) (BPSMA) were synthesized through free radical polymerization with styrene, maleic anhydride, and chain transfer monomer, 4-vinyl benzyl thiol. The successful synthesis of BPSMA was confirmed by a triple detection system including gel permeation chromatography, multiangle laser light scattering, and differential viscosity detectors, as well as thermal analysis (differential scanning calorimetry). This methodology proposes good prospects for scaling-up and thereby offers a wide range of branched alternating copolymers at low cost.

Photocatalytic reductive dechlorination of 2-chlorodibenzo-p-dioxin by Pd modified g-C3N4 photocatalysts under UV–vis irradiation: Efficacy, kinetics and mechanism

Jiafeng Ding,Gaoyuan Long,Yang Luo,Runze Sun,Mengxia Chen,Yajun Li,Yanfang Zhou,Xinhua Xu,Weirong Zhao

Polychlorinated dibenzo- p -dioxins (PCDDs), as a group of notorious anthropogenic environmental toxicants, are arguably ubiquitous in nature. In this study, we investigated the photocatalytic reductive dechlorination of 2-chlorodibenzo- p -dioxin (2-CDD) over Pd/g-C 3 N 4 catalysts under UV–vis irradiation. The g-C 3 N 4 and a series of Pd/g-C 3 N 4 catalysts were prepared by thermal polymerization and mechanical mixing-illumination method and characterized by XRD, TEM, BET, SEM and UV–vis DRS analyses. Among all the samples, the Pd/g-C 3 N 4 (5 wt%) yielded the optimal dechlorination activity with a total 2-CDD conversion of 54% within 4 h, and 76% of those converted 2-CDD were evolved to dibenzo- p -dioxin (DD). The kinetics of dechlorination could be described as pseudo-first-order decay model (R 2  > 0.84). Corresponding rate constants (k) increased from 0.052 to 0.17 h −1 with Pd contents up to 5 wt% and decreased to 0.13 h −1 with a 10 wt% of Pd. The enhanced activities originated from the surface plasmonic resonance (SPR) effect of Pd nanoparticles and the formation of Schottky barrier between Pd and g-C 3 N 4 , which extend the spectrum responsive range and suppress the charge recombination of g-C 3 N 4 . This is the first report on the photocatalytic reductive removal of PCDDs and may provide a new approach for PCDDs pollution control.

Common materials, extraordinary behavior: An ultrasensitive and enantioselective strategy for D-Tryptophan recognition based on electrochemical Au@p-L-cysteine chiral interface

Yanan Deng,Zihao Zhang,Yuanhao Pang,Xueying Zhou,Yu Wang,Yun Zhang,Yali Yuan

The poly-L-cysteine modified Au nanoparticles (Au@p-L-Cys) were constructed on electrode surface as a highly efficient chiral interface for tryptophan (Trp) enantiomers recognition via one step electropolymerization. With the aid of Cu 2+ , L-Cys residues and D-Trp target formed a sandwich complex D-Trp-Cu 2+ -L-Cys, while L-Trp was unable to form such complex due to the steric hindrance provided by the chiral interface, which was confirmed by the electrochemical and SEM results. With the introduction of ferricyanide probe, D-Trp produced significant current decrease while L-Trp produced a slight current increase, which implied the successful enantioselective recognition of Trp enantiomers (specifically D-Trp) in the true sense. This novel sensor showed a surprisingly wide linear range toward D-Trp of 6 × 10 −7  M to 1 × 10 −2  M, with a detection limit as low as 75 nM (S/N = 3). Moreover, the exclusive enantioselectivity toward D-Trp was discovered since other amino acids showed negligible interference to detection of D-Trp. The recovery of D-Trp in human serum was between 91.30 and 109.3%, which further verified the satisfying specificity and practicality of the proposed strategy. The coordination thermodynamics by UV–Vis spectroscopy and DFT simulation were also used to investigate the enantioselective mechanism. These results highlight the great potential of using Au@p-L-Cys to construct chiral interface for enantiomers recognition and hold the promise of practical application of electrochemical chiral sensors in fields like pharmaceutics and bioanalysis .

Synthesis of TiO2-loaded Co0.85Se thin films with heterostructure and their enhanced catalytic activity for p-nitrophenol reduction and hydrazine hydrate decomposition

Yong Zuo,Ji-Ming Song,He-Lin Niu,Chang-Jie Mao,Sheng-Yi Zhang,Yu-Hua Shen

P-nitrophenol (4-NP) and hydrazine hydrate are considered to be highly toxic pollutants in wastewater, and it is of great importance to remove them. Herein, TiO2-loaded Co0.85Se thin films with heterostructure were successfully synthesized by a hydrothermal route. The as-synthesized samples were characterized by x-ray diffraction, x-ray photoelectron spectroscopy, transmission electron microscopy and selective-area electron diffraction. The results demonstrate that TiO2 nanoparticles with a size of about 10 nm are easily loaded on the surface of graphene-like Co0.85Se nanofilms, and the NH3 · H2O plays an important role in the generation and crystallization of TiO2 nanoparticles. Brunauer–Emmett–Teller measurement shows that the obtained nanocomposites have a larger specific surface area (199.3 m2 g−1) than that of Co0.85Se nanofilms (55.17 m2 g−1) and TiO2 nanoparticles (19.49 m2 g−1). The catalytic tests indicate Co0.85Se–TiO2 nanofilms have the highest activity for 4-NP reduction and hydrazine hydrate decomposition within 10 min and 8 min, respectively, compared with the corresponding precursor Co0.85Se nanofilms and TiO2 nanoparticles. The enhanced catalytic performance can be attributed to the larger specific surface area and higher rate of interfacial charge transfer in the heterojunction than that of the single components. In addition, recycling tests show that the as-synthesized sample presents stable conversion efficiency for 4-NP reduction.

Preparation of superhydrophobic antistatic coatings from branched alternating copolymers P(St-alt-MAn) and carbon nanotubes based on organic–inorganic hybrid approach

Jingcheng Liu,Ren Liu,Yan Yuan,Shengwen Zhang,Xiaoya Liu

Novel superhydrophobic antistatic coatings were prepared from the branched alternating copolymers P(St- alt -MAn) and carbon nanotubes through a facile method. Pristine multiwalled carbon nanotubes (MWCNTs) were non-covalently modified by an organic–inorganic hybrid of the branched copolymers P(St- alt -MAn) and silica with the existence of γ-aminopropyl-triethoxysilane. The modified MWCNTs were mixed with tetraethyl orthosilicate in ethanol, coated with a fluoroalkylsilane, and then heat treated to obtain the superhydrophobic antistatic coatings. Scanning electron microscopy (SEM) showed that the coatings have a micrometer- and nanometer-scale hierarchical structure similar to that of lotus leaves with high water contact angles (>170°). In addition, the relationship between content of MWCNTs and the properties of the coatings, as well as the effect of cure temperature on contact angle values were investigated systematically.

Heteroatomic Interface Engineering of MOF-Derived Metal-Embedded P- and N-Codoped Zn Node Porous Polyhedral Carbon with Enhanced Sodium-Ion Storage

Siqi Zhu,Hong Yin,Yatong Wang,Kwan San Hui,Xi-Lin Wu,Wenjie Mai,Xiaoting Hong,Fuming Chen,Kwun Nam Hui

Amorphous-ordered mesoporous carbon materials are regarded as the most promising anode candidate for sodium-ion batteries (SIBs) owing to their eco-friendliness, abundance, thermal stability, and low price. However, poor rate, low initial Coulombic efficiency, and poor cycling performance have been the major challenges of SIBs. Herein, we successfully constructed a robust phosphorus and nitrogen-codoped Zn node porous polyhedral carbon polyhedron (P–N–Zn–C). The as-prepared P–N–Zn–C anode delivers outstanding electrochemical performance and ultrahigh stability and has achieved a remarkable capacity of 460 mA h g–1 at 100 mA g–1, long-term cycling stability of up to 100 cycles, and an excellent rate performance even at a current density of up to 1000 mA g–1. The remarkable performance can be ascribed to the enlarged interlayer distances of carbon and the existence of Zn node, which facilitate the insertion–extraction of Na ions. The first-principles density functional theory calculations revealed that the presence of P, N, and Zn could reduce the band gaps between the valence and conduction bands and accelerate the electron transfer reaction rate. This study underscores the potential importance of heteroatom doping as an effective strategy for improving the performance of carbon electrode materials.

A Covalent Heterostructure of Metal Phosphide Quantum Dots Anchored in N, P Co-doped Carbon Nanocapsules for Fast and Durable Lithium Storage

Xiangdong Ma,Chuang Ji,Xiaoyuan Yu,Yike Liu,Xunhui Xiong

Transition-metal phosphides (TMPs) anodes for lithium ion batteries (LIBs) usually show poor rate capability and rapid capacity degradation owing to their low electronic conductivities, huge volumetric changes, as well as inferior reversibility of the discharge product Li3P. Herein, a covalent heterostructure with TMPs quantum dots anchored in N, P co-doped carbon nanocapsules (NPC) has been prepared in which the P element in TMPs is simultaneously doped into the carbon matrix. As a proof of concept, Co2P quantum dots covalently anchored in NPC (Co2P QDs/NPC) is prepared and evaluated as an anode for LIBs. The Co2P QDs/NPC electrode not only demonstrates a high capacity and an extraordinary rate performance but also delivers an impressive cyclability with a high capacity retention of 102.5% after 1600 cycles, one of the best reported values for TMPs-based electrode materials for LIBs. The covalent heterostructure can facilitate the electron/ion transfer and maintain the structural stability during the intensive cycles. Moreover, density functional theory calculations demonstrate that the interfacial covalent coupling can enhance the electrochemical reversibility of the discharge product Li3P in the charge processes via lowering the conversion reaction energies. This work presents an effective interfacial engineering strategy for developing high-performance TMPs anodes for advanced LIBs.

Strong interlayer coupling in p-Te/n-CdSe van der Waals heterojunction for self-powered photodetectors with fast speed and high responsivity

Yanjie Hu,Xiaohui Song,Dongliang Jia,Wanhan Su,Xiaojing Lv,Lin Li,Xueping Li,Yong Yan,Yurong Jiang,Congxin Xia,Congxin Xia

Preparation of graphene/poly(p-phenylenebenzobisoxazole) composite fibers based on simultaneous zwitterion coating and chemical reduction of graphene oxide at room temperature

Jianqiang Guo,Guohu Guan,Wen Zhou,Chuncheng Li,Yaonan Xiao,Wenxiang Zhu,Liuchun Zheng

Zwitterion-coated reduced graphene oxide (rGO) was used in fabricating graphene/PBO composite fibers via in situ polymerization. The zwitterionic 1 : 1 adducts were formed by two monomers of PBO and they could be crystallized using rGO sheets as templates. Covalent bonds could be formed between GO and 4,6-diaminoresorcinol dihydrochloride (DAR·2HCl, a monomer for PBO) with GO being reduced simultaneously at room temperature. The structure of rGO sheets was well characterized and a mechanism including nucleophilic addition and E1 dehydration was proposed. Zwitterions could precipitate out from water rapidly and yet dissolve in PPA easily. Thereby, rGO sheets could be homogeneously dispersed in the PBO matrix as zwitterions dissolve and polymerize. By adjusting the feeding of zwitterion-coated rGO sheets, various composites with 0.1–3.0 wt% GO sheets incorporated were obtained. With very low rGO sheet content, both the mechanical properties and thermal stability of rGO/PBO fibers increased remarkably.

Acute hypobaric hypoxia attenuates the anti-fatigue effects of pitolisant by downregulating the expression of organic cation transporter 1 and P-glycoprotein

Gang Zhao,Yajuan Li,Mengyuan Liu,Wei Chang,Hui Shen,Junhui Xue,Fengzhou Liu

Objective: This study investigates the effects of acute hypobaric hypoxia (HH) on the anti-fatigue properties of pitolisant and explores the underlying mechanisms. The aim is to provide a theoretical basis for expanding its clinical indications and optimizing its use in individuals exposed to HH conditions.Methods: The anti-fatigue effects of pitolisant were evaluated using the water maze, novel object recognition, and rotating rod tests. Drug concentrations and dopamine levels were analyzed using High-Performance Liquid Chromatography-Mass Spectrometry/Mass Spectrometry (HPLC-MS/MS). Additionally, gene and protein expression levels of P-glycoprotein (P-gp) and organic cation transporter 1 (OCT1) were assessed to explore the mechanisms by which HH affects pitolisant’s pharmacodynamics.Results: A 40 mg/kg dose of pitolisant significantly improved learning, memory, cognitive, and motor functions in sleep-deprived mice under HH conditions (P < 0.05). Pharmacokinetic analysis revealed a reduction in pitolisant concentration in the brain under HH conditions. Furthermore, OCT1 protein expression decreased after 1 h and 1 day of HH exposure (P < 0.05), while P-gp expression decreased after 1 h (P < 0.05).Conclusion: HH possibly reduced pitolisant’s brain concentration and efficacy by altering the expression of OCT1 and P-gp transporters. A 40 mg/kg dose was necessary for an effective anti-fatigue response. Pitolisant shows potential for supporting circadian rhythm regulation in shift workers and individuals suffering from jet lag. When used under HH conditions, adjusting the dose and frequency may be necessary due to altered pharmacokinetics.

Sintering-resistant and active-species-adjustable Ni catalysts supported on P-doped biochar via nanopore-confined activation for efficient levulinic acid hydrogenation

Xiaohao Liu,Dali Han,Jinming Xia,Dongxu Yan,Rui Diao,Fenglei Qi,Zhenyu Wang,Lei Yang,Xiang Wu,Peiyong Ma,Ying Zhang

Nanopore-confining strategy is an effective way to inhibit catalyst sintering and improve catalytic performance. However, the expensive material precursors and complex preparation process greatly limit the scale utilization of this particularly structured catalyst. Herein, nanopore-confined catalysts (Ni@PAC) with adjustable active species were successfully prepared by a very simple method exploiting the characteristics of phosphoric acid-activated biochar (PAC). The abundant phosphorous functional groups in PAC confined Ni well in pores and significantly inhibited sintering through the spatial-confined effect of nanopore. Moreover, the evolution and migration of P functional groups can be regulated by changing the reduction temperature, and the modulation of active species of Ni metal or nickel phosphide can be achieved. Using biomass-based levulinic acid hydrogenation as the probe reaction, it was found that the catalytic activity of 20Ni@PAC-600 was one order of magnitude higher than that of the non-phosphated 20Ni/ZAC-600 catalyst, and γ-valerolactone could be selectively prepared at near atmospheric pressure (1 bar). The formation of Ni2P and the spatial-confined effect of nanopore could be the main reasons for the high catalytic activity.

1.82 wt.% Pt/N, P co-doped carbon overwhelms 20 wt.% Pt/C as a high-efficiency electrocatalyst for hydrogen evolution reaction

Wang Changhong,Hu Feng,Yang Hongchao,Zhang Yejun,Lu Huan,Wang Qiangbin

Cost-effective electrocatalysts for the hydrogen evolution reaction (HER) play a key role in the field of renewable energy. Although tremendous efforts have been devoted to the search of alternative materials, Pt/C is still the most efficient electrocatalyst for the HER. Nevertheless, decreasing the loading of Pt in the designed eletrocatalysts is of significance. However, with low Pt loading, it is challenging to maintain excellent catalytic performance. Herein, a new catalyst (Pt/NPC) was prepared by dispersing Pt nanoparticles (PtNPs) with an average diameter of 1.8 nm over a three-dimensional (3D) carbon network co-doped with N and P. Because of the high electronegativity of the N and P dopants, PtNPs were uniformly dispersed on the carbon network via high electronic affinity between Pt and carbon, affording a Pt/NPC catalyst; Pt/NPC exhibited superior HER activity, attributed to the down-shift of the Pt d-band caused by the donation of charge from N and P to Pt. The results show that Pt/NPC with an ultralow Pt loading of 1.82 wt.% exhibits excellent HER performance, which corresponds to a HER mass activity 20.6-fold greater than that observed for commercial 20% Pt/C at an overpotential of 20 mV vs. RHE.