查找使用阿拉丁产品的科研文献

Host-guest engineering in a two-dimensional anionic porphyrinic metal-organic framework via cationic bodipy encapsulation for boosting photocatalytic H₂ evolution

Li-Lei Zhang,Xing-Yu Liu,Yu-Lan Wang,Ying Li,Xiao-Ge Zhu,Rong-Hui Cao,Hui-Ju Zhang,Xi-Yan Dong,Jian-Hua Qin

The development of efficient and stable photocatalysts for solar-driven hydrogen production remains a significant challenge, primarily limited by inadequate light harvesting and rapid charge recombination. This work addresses these issues through the rational design of a host-guest system within a metal-organic framework (MOF). We report a novel two-dimensional anionic porphyrinic MOF ( 1 ) synthesized using 1-butyl-3-methylimidazolium (BMI) as a structure-directing agent, and replaced the inert BMI guests with photoactive 4,4-Difluoro-8-(1-methylpyridin-4-ium-4-yl)-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene (Bodipy)-based cations by cationic exchange strategy, yielding the composite Bodipy@1 . The Bodipy units act as complementary antennas, broadening the visible-light absorption range, while the favorable energy-level alignment between the porphyrinic host (donor) and the Bodipy guest (acceptor) establishes an efficient intramolecular charge-transfer pathway. Density functional theory calculations and spectroscopic studies confirm a spatial separation of frontier orbitals, with the highest occupied crystal orbital localized on the porphyrin linker and the lowest unoccupied crystal orbital on the Bodipy cation, which effectively suppresses charge-carrier recombination. Consequently, Bodipy@1 exhibits a remarkable enhancement in photocatalytic hydrogen evolution activity (∼2.5 mmol·g −1 ·h −1 ), outperforming the pristine MOF 1 . This work highlights a potent strategy of energy-level engineering via host-guest assembly, demonstrating that precise post-synthetic modification of anionic MOFs with functional cations is a powerful avenue for designing advanced, stable photocatalysts for solar fuel production. A 2D anionic porphyrinic MOF host undergoes post-synthetic cation exchange, replacing inert [BMI] + with photoactive Bodipy cations. The favorable energy-level alignment drives intramolecular electron transfer from the porphyrin linker (donor) to the Bodipy guest (acceptor), achieving spatial charge separation. This, combined with broadened light absorption, leads to significantly enhanced photocatalytic H₂ evolution. Download: Download high-res image (140KB) Download: Download full-size image

Achieving Efficient Hydrogen Evolution of CNT@Ag@ZnIn2S4 Photocatalyst Under Visible Light by Regulating H─S Antibonding Orbital Occupancy via Ag

Jiacheng Zheng,Yulong Deng,Wenting Chen,Chengliao Deng,Xiaoming Cai,Jinming Cai,Honglin Tan

Zinc indium sulfide (ZnIn 2 S 4 , ZIS), a visible-light-responsive photocatalyst, has garnered significant attention due to its facile synthesis, high stability, suitable band gap, and abundant active sites. This study innovatively constructed a CNT@Ag@ZIS tubular structure, introducing Ag mediators as electron donors at the CNT-ZIS interface. Results demonstrate that the Ag mediators establish clear interfacial contact with both hexagonal ZIS and CNT. Consequently, ZIS exhibits markedly enhanced photocurrent response and improved separation efficiency of photogenerated charge carriers. The catalyst achieved a remarkable hydrogen evolution rate of 18.44 mmol g −1 h −1 , representing an 8.7-fold enhancement over pristine ZIS. The study revealed that Ag, with its high Fermi level, facilitates interfacial electron transfer to ZIS. This induces a downshift of the p-band center (3p orbitals of S) in ZIS, simultaneously prolonging the H─S bond length and increasing the antibonding orbital occupation. This electron restructuring creates electron-rich S (2+δ)− active sites, substantially lowering the H 2 desorption energy barrier. Thus, the surface reaction kinetics of the sulfide are optimized through a regulation strategy targeting antibonding orbitals.

Hot-pressed CAU-10-H/PEEK composite films with robust thermal stability and moisture resistance for high-frequency low-dielectric applications

Hao Yu,Jiakai Shi,Jiaqi Wen,Shi Liu,Jingyu Cai,Linxi Hou

Permittivity is a key parameter characterising the polarisation capacity of a dielectric, and directly influences a material’s signal transmission and energy storage properties. As electronic devices evolve towards higher frequencies and greater integration, there is an increasing demand for polymer materials that combine low dielectric constant with excellent thermal and environmental stability. In this study, a aluminium-based metal-organic framework material CAU-10-H, which exhibits negative thermal expansion, was synthesised using the hydrothermal method and incorporated into PEEK matrix by hot-press to prepare CAU-10-H/PEEK composite films. The as-obtained CAU-10-H is relatively well dispersed within the PEEK matrix at low-to-moderate filler loadings, while its incorporation is associated with a reduction in the dielectric constant of the composite. The reduced dielectric response is mainly attributed to the introduction of low-polarity nanoporous domains, while the increase in free volume fraction may also contribute to this behaviour. When the filler content is 5 wt%, the composite exhibits a low die This may be attributed to the following factors:lectric constant across the 2–18 GHz frequency range, with an average value as low as 2.45, whilst the thermal decomposition temperature is above 500℃. In addition, this composite material offers moisture resistance, excellent dimensional stability, outstanding frequency stability and good signal integrity. This study provides new insights into the regulation of the high-frequency dielectric properties and stability of polymer composites using microporous materials with negative thermal expansion characteristics. Download: Download high-res image (181KB) Download: Download full-size image Owing to the inherent microporous structure of MOFs and their interaction with the polymer matrix, this composite material achieves a dual reduction in both the dielectric constant and dielectric loss at high frequencies, whilst exhibiting excellent thermal stability and superior moisture resistance.

Aqueous extract of Amydrium sinense (Engl.) H. Li alleviates hepatic fibrosis by suppressing hepatic stellate cell activation through inhibiting Stat3 signaling

Li Jingyan,Wu Bingmin,Zeng Lishan,Lin Ying,Chen Qiuhe,Wang Haixia,An Lin,Zhang Jiajun,Chen Siyan,Huang Junying,Zhan Ruoting,Zhang Guifang

Background: The present study aimed to investigate the protective effect of the water extract of Amydrium sinense (Engl.) H. Li (ASWE) against hepatic fibrosis (HF) and clarify the underlying mechanism.Methods: The chemical components of ASWE were analysed by a Q-Orbitrap high-resolution mass spectrometer. In our study, an in vivo hepatic fibrosis mouse model was established via an intraperitoneal injection of olive oil containing 20% CCl4. In vitro experiments were conducted using a hepatic stellate cell line (HSC-T6) and RAW 264.7 cell line. A CCK-8 assay was performed to assess the cell viability of HSC-T6 and RAW264.7 cells treated with ASWE. Immunofluorescence staining was used to examine the intracellular localization of signal transducer and activator of transcription 3 (Stat3). Stat3 was overexpressed to analyse the role of Stat3 in the effect of ASWE on HF.Results: Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses showed that candidate targets of ASWE, associated with protective effects against hepatic fibrosis, were related to inflammation response. ASWE ameliorated CCl4-induced liver pathological damage and reduced the liver index and alanine transaminase (ALT) and aspartate transaminase (AST) levels. ASWE also decreased the serum levels of collagen Ⅰ (Col Ⅰ) and hydroxyproline (Hyp) in CCl4-treated mice. In addition, the expression of fibrosis markers, including α-SMA protein and Acta2, Col1a1, and Col3a1 mRNA, was downregulated by ASWE treatment in vivo. The expression of these fibrosis markers was also decreased by treatment with ASWE in HSC-T6 cells. Moreover, ASWE decreased the expression of inflammatory markers, including the Tnf-α, Il6 and Il1β, in RAW264.7 cells. ASWE decreased the phosphorylation of Stat3 and total Stat3 expression and reduced the mRNA expression of the Stat3 gene in vivo and in vitro. ASWE also inhibited the nuclear shuttling of Stat3. Overexpression of Stat3 weakened the therapeutic effect of ASWE and accelerated the progression of HF.Conclusion: The results show that ASWE protects against CCl4-induced liver injury by suppressing fibrosis, inflammation, HSC activation and the Stat3 signaling pathway, which might lead to a new approach for preventing HF.

A robust and self-healing elastomer achieved by a thio-β-diketone-Cu(II) coordination and H-bonding dual crosslinked system

Xiaoming An,Jie Liu,Jia-Han Zhang,Xinxin Huang,Tangsong Zhu,Hongping Yan,Xudong Jia,Qiuhong Zhang

Elastomers possessing good mechanical strength and self-healing capability are showing great importance in stretchable electronics, since they can play the role of robust substrates for devices, and prolong the service life of devices. However, it is hard to balance the trade-off between the high mechanical strength and self-healing ability. Here we propose the synergetic strategy via combining thio-β-diketone-Cu2+ metal–ligand (M–L) coordination with hydrogen bonds in one system, through which high mechanical strength, good elasticity and self-healing ability are achieved. The elastomer displays excellent mechanical performances (with a fracture strength of 4.35 MPa and a fracture strain of 3400%). Meanwhile, the elastomer can realize a high self-healing efficiency (94%) within only 3 hours at 80 °C. X-ray absorption fine structure (XAFS) analysis demonstrates the reconfiguration of M–L coordination at the molecular level, and small angle X-ray scattering (SAXS) during stretching demonstrates the microphase structure change of the polymer at the nanoscale level. Based on the elastomer, a self-healable pressure sensor and a self-healable strain sensor are fabricated.

Crassifoside H ameliorates depressant behavior in chronic unpredictable mild stress rats by improving HPA axis dysfunction and inhibiting inflammation in hippocampus

Huina Li,Kefan Wu,Yue Zhang,Ning Li,Kaijin Wang

Synergistic functionalization of h-BN by mechanical exfoliation and PEI chemical modification for enhancing the corrosion resistance of waterborne epoxy coating

Youqing Wu,Yi He,Taigang Zhou,Chunlin Chen,Fei Zhong,Yunqing Xia,Peng Xie,Chen Zhang

The hexagonal boron nitride (h-BN) has extensive promise for metal corrosion protection due to its good impermeability to gas and liquid. However, the practical application of h-BN in polymer composites is limited by surface incompatibility. Herein, we prepared a homogeneous dispersion of h-BN in water-borne epoxy (EP) matrix by mechanical exfoliation and chemical modification, in which the h-BN powder was ultrasonic to obtain partially hydroxylated BN and the products were modified with water-soluble branched poly-ethyleneimine (PEI) via Lewis acid-base interaction. The electrochemical test (EIS and potentiodynamic polarization) and salt spray test in NaCl solution were used to analyze the corrosion resistance performance of composite coatings. The results show that PEI-BNNS/EP coating has superior and long-term anticorrosion performance for P110 mild steel. The impedance modulus (Z f  = 0.01 Hz) of PEI-BNNS/EP still has 6.63 × 10 7 Ω cm 2 after 70 days immersion in the 3.5 wt. % NaCl solution. The PEI has an important role for enhancing the anticorrosion property of PEI-BNNS/EP coating, which increases the dispersibility and compatibility of h-BN in EP and the crosslink density of epoxy resin. Our study gives a strategy for the preparation of easy dispersion h-BN nanosheets in large quantities, thus broadening its practical application in the polymer material field.

Multilayered Ruddlesden–Popper perovskite hybrids with alternative organic spacers of 4-XC6H4C2H4NH2 (where X = H, Br, Cl) for solar cell applications

Gan Xiaoyan,Zhao Wenhui,Xu Tianye,Liang Yun,Guo Liling,Liu Hanxing

Two-dimensional (2D) organic–inorganic perovskite hybrid materials with enhanced stability have attracted wide attention in optoelectronic field in recent years. Efforts of exploring new 2D perovskites with various organic or inorganic components have been devoted to further improve their solar cell efficiencies. In this work, three structurally similar spacer cations of phenylethylammonium (PEA), 4-bromophenylethylammonium (BPEA) and 4-chlorophenylethylammonium (CPEA) are selected to prepare multilayered 2D perovskites. It is found that the introduction of halogen atoms in the organic cations positively influences the film quality, light absorption, charge transport, device performance and moisture stability of the resulting perovskites. The (BPEA) 2 (MA) 4 Pb 5 I 16 and (CPEA) 2 (MA) 4 Pb 5 I 16 perovskites exhibit efficiencies of 7.38% and 10.88%, respectively, which are much higher than that of (PEA) 2 (MA) 4 Pb 5 I 16 (3.98%). Owning to the larger size and bigger electronegativity of halogen atom in spacer cations, the PCE of unsealed BPEA- and CPEA-based 2D perovskite devices maintains 73% and 63% of their original efficiency after 720 h exposure to 60% humid air, while the PEA-based 2D device decreases to 52% of its initial PCE. Our work demonstrates new insight to modify the quality and stability of 2D perovskite hybrids, highlighting the validity of molecule design of organic cations in improving the efficiency and stability of 2D perovskite solar cells.

Classical photopolymerization kinetics, exceptional gelation, and improved diffraction efficiency and driving voltage in scaffolding morphological H-PDLCs afforded using a photoinitibitor

Haiyan Peng,Guannan Chen,Mingli Ni,Yan Yan,Jiaqing Zhuang,V. A. L. Roy,Robert K. Y. Li,Xiaolin Xie

Holographic polymer dispersed liquid crystals (H-PDLCs) pertain to one type of intriguing switchable electro-optical device, and there is a constant need to quantitatively understand the photopolymerization kinetics and gelation process during the formation of H-PDLCs for the purpose of improving the diffraction efficiency and driving voltage. Herein, we quantitatively investigate the effect of the photoinitibitor composed of 3,3′-carbonylbis(7-diethylaminocoumarin) (KCD) and N-phenylglycine (NPG), with initiation and inhibition functions simultaneously generated under monochromatic illumination, on the formation of H-PDLCs. The outcomes reveal that an augmentation of KCD loading from 0.3 × 10−3 to 1.4 × 10−3 mol L−1 dramatically promotes the photopolymerization rate and monomer conversion. Reversely, a further increase in KCD content drastically depresses photopolymerization. The numerical deduction shows that the kinetics complies with the classical photopolymerization kinetics characteristics in the full range of the KCD content. Counterintuitively, the gelation time almost keeps constant when the KCD content is less than 1.8 × 10−3 mol L−1, and then is able to grow by more than 4 times when the KCD loading further increases. Ketyl radical inhibition, which subsequently results in shortened weight-average chain lengths and increased gel point conversions, is believed to account for the kinetics and exceptional gelation behaviors. H-PDLCs with a scaffolding morphology are formed, and with an augmentation of the KCD content, the segregation degree and diffraction efficiency significantly improve from zero to 64% and 78 ± 11%, respectively, and then level off, allowing for the facile fabrication of glass-free colored 3D images; while the critical driving voltage gradually decreases from 8.9 ± 1.0 to 4.6 ± 0.7 V μm−1.

Highly catalytic performance for the selective C–H bond oxidation of p-chlorotoluene over Co, Cr co-doped OMS-2 catalyst

Shandi Zhong,Cai Xu,Quanfu Long,Hang Zhou,Jianhai Yang,Jia Guo,Xiaozhong Wang,Liyan Dai

Using O 2 as an oxidant, developing a non-noble metal catalyst for the selective catalytic C–H bond oxidation of p-chlorotoluene is desirable and challenging. In this work, a series of Co, Cr co-doped OMS-2 (Octahedral Molecular Sieve-2) catalysts were prepared by a conventional refluxing method. It was found that the incorporation of Co and Cr improved the catalytic activity for the selective oxidation of p-chlorotoluene to p-chlorobenzaldehyde. Among these catalysts, CoCr/OMS-2 (Co: Cr = 1: 1, mass ratio), the best catalyst, shows that the conversion and the selectivity of p-chlorobenzaldehyde is 94.8 % and 94.3 %, respectively. The enhanced catalytic activity was due to the larger specific surface area and even dispersion of active components. The characterization results also disclosed that the co-doping of Co and Cr increased the oxygen vacancy and enhanced the ability to activate the surface lattice oxygen. Additionally, density functional theory calculations demonstrated that co-doping of Co and Cr promoted the adsorption of p-chlorotoluene and O 2 , and decreased the energy barrier of rate-determining step (the conversion of p-chlorobenzyl alcohol to p-chlorobenzaldehyde). Besides, when H 2 O was added to the reaction system as the second solvent, the activation and dissociation of O 2 , and the formation of p-chlorobenzaldehyde were facilitated, in agreement with the experimental results. This work demonstrated the promotional effect of Co, Cr co-doped into OMS-2 catalyst and the role of H 2 O for the selective oxidation of p-chlorotoluene.

Synergistic effect of dual-modification strategy on thermal conductivity and thermal stability of h-BN/silicone rubber composites: Experiments and simulations

Wei Yang,Yichao Lin,Yanqi Zhu,Chenxia Zhen,Weihao Tao,Yanlong Luo,Xiujuan Wang

This study aims to investigate the effect of the modification strategy of hexagonal boron nitride (h-BN) on the interfacial heat transfer behavior of the composite. Dual modification of h-BN, including covalent and non-covalent modifications, was achieved by combining 6-aminohexanoic acid (ACA)-assisted wet ball milling and tannic acid (TA) surface deposition. Molecular dynamics (MD) simulations show that the interfacial thermal resistance of the covalently modified and the non-covalently modified regions of the composite system is reduced by 19.7 % and 40.9 %, respectively, and the interfacial thermal conductivity is increased by 24.5 % and 88.0 %, respectively. Meanwhile, thermogravimetric analysis demonstrated a 9 °C and 23.7 °C increase in the maximum weight loss temperature of the dual-modified composites compared to that of the two single-modified composites. The synergistic mechanism of the dual modification strategy in improving the interfacial interaction and enhancing the phonon vibration power spectrum of the composites is revealed by MD simulations. This study contributes to a deep understanding of the thermal conductivity mechanism of filled thermal interface materials. It guides the design of modified filler-filled high thermal conductivity rubber-based composites.

Intermolecular H-bonding and tetrameric π-stacking enable dual "mortise-and-tenon" jointed S-scheme supramolecular arrays for efficient carrier separation

Zhuo Li,EnZhou Liu,Carlota Bozal-Ginesta,HaiXia Ma,HuiYong Chen,Bing Wang

The rational design of stable charge-transfer pathways remains a critical challenge in advancing S-scheme photocatalytic systems. Herein, we demonstrate a hydrogen-bond-engineered dual mortise-and-tenon supramolecular architecture using precisely tailored H 12 SubPcB-OCONapOH (SubPc-5) molecules, which synergistically enhance interfacial carrier dynamics and structural robustness. The SubPc-5/TiO 2 heterojunction, constructed through π-π-directed self-assembly, achieves exceptional photocatalytic degradation of oxytetracycline (90%) and tetracycline (99%) within 180   minutes, outperforming pristine TiO 2 by 3–4.5-fold in reaction kinetics. Multimodal mechanistic investigations, including in situ light-irradiated Kelvin probe analysis, synchronous irradiation X-ray photoelectron spectroscopy (SI-XPS), and density functional theory (DFT) calculations, unambiguously verify the S-scheme charge transfer between TiO 2 and SubPc-5. Theoretical investigations reveal that O 2 molecules adsorbed at the O-site on the TiO 2 (101) surface more efficiently capture photogenerated electrons compared to the Ti-site. This work pioneers a supramolecular engineering strategy for constructing mechanically stable and electronically efficient photocatalytic systems, highlighting the transformative potential of mortise-and-tenon nanostructures in environmental remediation applications.