查找使用阿拉丁产品的科研文献

Enhancing photocatalytic norfloxacin degradation: Synergistic engineering of heterojunctions and oxygen vacancies in Fe-based MIL

Yixuan Liu,Jiamin Wei,Qi Zong,Chaoyue Chen,Tinghai Yang,Weiqiao Liu

Constructing cost-efficient and robust Fe-MIL-based photocatalysts for efficiently photodegrading antibiotics is highly appealing, however, their intrinsic defects, particularly unsatisfied visible light harvesting efficiency and rapid recombination of charge carriers, provide significant challenges. Herein, oxygen-vacancy-rich Bi 2 WO 6 -OVs/NH 2 -MIL-88B (Fe) composites were successfully constructed via a two-step approach consisting of a hydrothermal reaction followed by NaBH 4 treatment. The chemical compositions, microstructure, morphology, as well as optical properties of the as-prepared samples were thoroughly established. The optimized Bi 2 WO 6 -OV(40)/NH 2 -MIL-88B(Fe) photocatalyst exhibited the maximum photocatalytic efficiency (95.3 %) for the photodegradation of Norfloxacin (NOR), which was considerably greater than that of the heterostructure (56.9 %). The enhancement of photocatalytic performance can be attributed to the collaborative effect between oxygen vacancies and hybrid heterojunctions, which jointly enhances photoexcited electron generation and accelerates charge transfer. Furthermore, from the perspective of practical applications, the effects of pH, NOR concentration, and photocatalyst reuse were carefully investigated. The radical trapping experiments and ESR results verified that superoxide radicals (•O 2 − ), holes (h + ), and hydroxyl radicals (•OH) were the main active species in the NOR degradation process, and the possible photocatalytic mechanism was speculated accordingly. This research provides a promising approach to fabricating Fe-MOF-based heterojunctions with surface oxygen vacancy defect modification for the photodegradation of antibiotics.

Fe/Cl/N triply-doped bamboo-like structure wrapped with Fe3C nanoparticles for electrochemical selective nitrite detection

Lufang He,Zhuo Liu,Yuchi Zhang,Le Han,Yan Xu

Nitrite is commonly found in the natural environment and in everyday human activities. However, excessive nitrite consumption can potentially harm human health. Consequently, it is crucial to develop a reliable and sensitive method for nitrite detection. In this work, trichloroacetic acid functionalized Cl-Fe-MIL-88B metal-organic framework is obtained through nucleophilic reaction between animated Fe-MIL-88B and trichloroacetic acid, which is then annealed with melamine in an N 2 atmosphere to produce the Fe/Cl/N triply-doped bamboo-like carbon nanotubes (CNTs) wrapped with Fe 3 C nanoparticles. Owing to the effective doping of Fe/Cl/N elements, the charge distribution and chemical activity of the bamboo-like structure are tailored, greatly improving the conductivity and facilitating electron transfer of the composite for potential electrocatalytic reaction. The Fe 3 C nanoparticles wrapped inside the CNTs contribute to expose more active sites and provide effective surface area. Accordingly, the Fe/Cl/N doped bamboo-like structure modified glassy carbon electrode shows excellent electrochemical nitrite sensing properties with a high sensitivity of 1060 µA cm −2 mM −1 , a low detection limit of 0.61 µM in a wide linear concentration range of 5–5000 μM, as well as good anti-interference and long-term stability. Also, the electrochemical sensor has a satisfactory recovery rate for detecting nitrite ions in spiked milk samples. This work proposes a simple precursor chlorination and pyrolysis strategy to obtain metal-filled bamboo-like structure with high electrical conductivity and electrocatalytic properties, endowing great potential in food safety and environment monitoring.

Interfacial Co–O–Fe bonding in novel amorphous NiCo-ZIF@MIL-100 as efficient active sites enabling electrocatalytic water oxidation

Tianhao Yu,Peng Gao,Hong Du,Ling Dong

Metal–organic frameworks (MOFs) have recently been reported as promising catalysts for the oxygen evolution reaction (OER). Hence, we chose hydroxyl-rich 2,5-dihydroxyterephthalic acid as the ligand to prepare a novel MIL-100 and wrapped it on the NiCo-ZIF-67 surface to obtain an amorphous hollow material (NiCo-ZIF-67@Fe-MIL-100, denoted as NiCo-ZIF@MIL). The composite material presents a low overpotential (η ≈ 139 mV @ 10 mA cm−2), a small Tafel slope (119 mV dec−1) and great stability for the OER in 1 M KOH solution. Density Functional Theory (DFT) calculations show that the hydroxyl-rich structure, which accelerates OH− transfer and promotes the formation of the Co–O–Fe bridge, effectively reduces the reaction energy barrier (from 2.67 eV for NiCo-ZIF-67 to 2.08 eV for NiCo-ZIF@MIL). This work provides an important reference for the development of double-MOF materials.

Selective recognition of 6-mercaptopurine based on luminescent metal–organic frameworks Fe-MIL-88NH2

Zhengjuan Sun,Yali Liu,Yuanfang Li

A novel and rapid spectrofluorometry method for the recognition of 6-mercaptopurine (6-MP) has been developed based on luminescent metal–organic frameworks Fe-MIL-88NH 2 as fluorescent probe. The strong fluorescence of Fe-MIL-88NH 2 at 430   nm could be quenched by 6-MP directly, and the Fe-MIL-88NH 2 shows high selectivity for 6-MP compared to other thiol-containing amino acids such as homocysteine (Hcy), cysteine (Cys), glutathione (GSH), etc. Under optimal conditions, the relative fluorescence intensity was linearly proportional to the concentration of 6-MP in the range of 5–600   μM with the detection limit at 1.17   μM (S/N   =   3). Furthermore, the present approach has been successfully applied to the determination of 6-MP in human serum samples. The possible fluorescence quenching mechanism has also been investigated, where it is revealed that the quenching was attributed to competition of absorption of the light source energy as well as electron transfer between Fe-MIL-88NH 2 and 6-MP.

Co-Fe/MIL-101(Cr) hybrid catalysts: Preparation and their electrocatalysis in oxygen reduction reaction

Guoru Li,Xiaobo He,Fengxiang Yin,Biaohua Chen,Huaqiang Yin

The development of highly efficient electrocatalysts with low cost for oxygen reduction reaction (ORR) is urgently required for metal-air batteries and fuel cells. In this work, Fe Co/MIL-101(Cr) with various molar ratios of Fe/Co as hybrid catalysts was prepared by a facile and mild impregnation method. MIL-101(Cr) increased the specific surface areas of the hybrid catalysts, thus improving the dispersion of Fe and Co species at their surfaces. The effects of Fe and Co species on ORR activity of the hybrid catalysts were investigated. It is found that the synergistic effects between the well-dispersed Fe and Co species contribute mainly to ORR activity. More specifically, Fe species exert a partial-charge-transfer-activation effect on Co ones, which reduces the charge transfer resistance and thus improves the catalytic activity . As a result, Fe Co/MIL-101(Cr) showed the excellent ORR activity, in which Co 50 Fe 50 /MIL-101(Cr) exhibited the superior ORR activity to the other prepared hybrid catalysts.

Rapid and selective adsorption of a typical aromatic organophosphorus flame retardant on MIL-101-based metal–organic frameworks

Hui Su,Jiaxin Lv,Liansheng Yang,Li Feng,Yongze Liu,Ziwen Du,Liqiu Zhang

The pollution of aromatic organophosphorus flame retardants (aromatic OPFRs) in aquatic environments has drawn great attention over the last few years. Two MIL-101-based metal–organic frameworks (Cr-MIL-101 and Fe-MIL-101-NH2) which possess ordered mesoporous cavities (2.9 and 3.4 nm) and aromatic structures were chosen and prepared to selectively adsorb a typical aromatic OPFR [triphenyl phosphate (TPhP)] from aqueous solution. Pore distribution analysis showed that Cr-MIL-101 and Fe-MIL-101-NH2 had both a mesoporous structure (2–3.5 nm) and microporous structure (1–2 nm), conducive to diffusion and adsorption of TPhP molecules. Compared with Fe-MIL-101-NH2 as well as commercial activated carbon, Cr-MIL-101 showed rapid and efficient adsorption for TPhP, and its initial sorption velocity (v0) calculated from the pseudo-second-order model was up to 568.18 μmol g−1 h−1. The adsorption equilibrium of TPhP on the Cr-MIL-101 was almost achieved within 12 h, while the equilibrium time of other adsorbents required more than 48 h. The study of selective adsorption found that Cr-MIL-101 had a higher sorption amount for aromatic OPFRs than alkyl-OPFRs and other aromatic compounds with different chemical structures. Cr-MIL-101 was able to keep a steady selective adsorption for TPhP in the presence of co-existing aromatic compounds. Based on the analysis of Kow, molecular structure and further density functional theory calculations, hydrophobic interactions may play a dominant role in the selective adsorption process of TPhP, and π–π interactions may be also involved. Cr-MIL-101 exhibits reusability and promising potential to rapidly and selectively remove aromatic OPFR in environmental remediation.

Pt@Fe-MIL-88 Enabled Natural-Enzyme-Free Dual-Mode Assay for Highly Selective Detection of Glyphosate

Peng Huajie,Gao Di,Xiao Zhengyue,Yue Zhixiang,Xu Peng,Qiu Ping

Compared with natural-enzyme-based detection strategies, nanozymes offer notable advantages in stability, environmental tolerance, and cost-effectiveness. In this study, we designed and synthesized a Pt@Fe-MIL-88 composite with both oxidase (OXD)-like activity and intrinsic fluorescence. The material efficiently catalyzes 3,3 ′ ,5,5 ′ -tetramethylbenzidine (TMB) oxidation, generating a color change while quenching its fluorescence. Glyphosate (Gly) specifically inhibits the OXD-like activity of Pt@Fe-MIL-88, reducing oxTMB production and thereby alleviating fluorescence quenching, enabling dual colorimetric and fluorometric signal readout. The inhibition mechanism was elucidated through FTIR, XRD, XPS characterization, molecular dynamics simulations, and DFT calculations. Accordingly, a natural-enzyme-free, colorimetric-fluorometric dual-mode sensing platform for Gly was established. The platform exhibits high sensitivity, excellent selectivity, and strong anti-interference capability, with accuracy and reliability validated by spike recovery tests in real samples. This work presents a new strategy for developing stable, rapid, and low-cost multimodal detection methods for pesticide residues.

Optimizing the Coordination Structure of Quasi Fe MIL-101 for a Colorimetric Biosensing Platform to Detect Galactose

Chunxia Ma,Limin Ma,Yaoyao Chen,Rui Han,Dongming Xu,Huanhuan Xing,Shasha Lu,Dewen Wang,Xiurong Yang

A major hurdle in nanozyme design is the difficulty of rationally tuning the coordination and electronic states of active sites, which are typically locked by the material’s rigid framework or surface composition. In this study, we address this limitation by developing a series of Fe-based quasi metal–organic framework nanozymes having a succulent appearance, denoted as Qx-MIL, through controlling the calcination of MIL. Partial decomposition of terephthalic acid ligands during heating increases the electron density of Fe active centers, reduces their coordination number, and generates asymmetric unsaturated Fe sites. These structural modifications enhance electron transfer, improve intermediate adsorption, promote the hydroxyl radical formation, and lower the energy barrier of the rate-determining step. As a result, Q400-MIL exhibits remarkable peroxidase-like activity and enhanced reaction kinetics. Leveraging this superior enzyme-mimicking performance, we constructed a galactose-oxidase-cascade colorimetric biosensor for the sensitive and selective detection of galactose. This work not only validates the high enzymatic activity and bioapplication potential of quasi MOF nanomaterials but also provides a simple and effective strategy for precisely engineering the active sites of nanozymes to broaden their functional scope.

Polydopamine-Modified Metal–Organic Frameworks, NH2-Fe-MIL-101, as pH-Sensitive Nanocarriers for Controlled Pesticide Release

Yongpan Shan,Chunli Xu,Hongjun Zhang,Huiping Chen,Muhammad Bilal,Shujun Niu,Lidong Cao,Qiliang Huang

Recently, metal–organic frameworks (MOFs) have become a dazzling star among porous materials used in many fields. Considering their intriguing features, MOFs have great prospects for application in the field of sustainable agriculture, especially as versatile pesticide-delivery vehicles. However, the study of MOF-based platforms for controlled pesticide release has just begun. Controlled pesticide release responsive to environmental stimuli is highly desirable for decreased agrochemical input, improved control efficacy and diminished adverse effects. In this work, simple, octahedral, iron-based MOFs (NH2-Fe-MIL-101) were synthesized through a microwave-assisted solvothermal method using Fe3+as the node and 2-aminoterephthalic acid as the organic ligand. Diniconazole (Dini), as a model fungicide, was loaded into NH2-Fe-MIL-101 to afford Dini@NH2-Fe-MIL-101 with a satisfactory loading content of 28.1%. The subsequent polydopamine (PDA) modification could endow Dini with pH-sensitive release patterns. The release of Dini from PDA@Dini@NH2-Fe-MIL-101 was much faster in an acidic medium compared to that in neutral and basic media. Moreover, Dini@NH2-Fe-MIL-101 and PDA@Dini@NH2-Fe-MIL-101 displayed good bioactivities against the pathogenic fungus causing wheat head scab (Fusarium graminearum). This research sought to reveal the feasibility of versatile MOFs as a pesticide-delivery platform in sustainable crop protection.Keywords:metal–organic framework;polydopamine;pesticide;pH-sensitive release;fungicidal activity

Selective Oxidation of Acetoin to Diacetyl by Superoxo Species on Fe-MIL-88B_NH2 and NHPI under Oxic Conditions

Chong Zhang,Yu-Dong Shan,Yi-Ying Lin,Yu-Le Wang,Zheng Yang,Yong Liu,Song-Hai Wu,Xu Han

Diacetyl (2,3-butanedione) is an important ingredient used in the food and perfume industries, whose synthesis is largely constrained by environmental pollution and low selectivity. In this study, Fe-MIL-88B_NH2 has been successfully synthesized via the microwave-assisted solvothermal method, which exhibits high reactivity in acetoin oxidation, affording 81.3% conversion and 95.8% selectivity toward diacetyl under mild conditions in the presence of NHPI (N-hydroxyphthalimide). Raman and a series of characterizations reveal that O2 is activated by surface Fe(II) on Fe-MIL-88B_NH2 with the generation of ≡Fe-OO• superoxo, which then abstracts H from acetoin with the formation of diacetyl and H2O2. Quenching experiments indicate that ≡Fe-OO• superoxo on Fe-MIL-88B_NH2 is the primary oxidizing species in the oxidation of acetoin. EPR and DPD analyses further reveal that the NHPI/PINO cycle effectively shuttles H from the acetoin to ≡Fe-OO• superoxo, thus enhancing the oxidation efficiency of acetoin. This study enriches our understanding on the importance of surface superoxo species and the H-shuttle in the selective oxidation of alcohols toward ketones.

Synthesis of Uniformly Covered Fe-MOF@COF Heterostructures for Boosting Photo-Fenton Catalysis

Zhang Xue-Feng,Chang Tian-Long,Guo Na,Jia Guo-Liang,Li Xiao-Bing,Zhao Zhao-Ye,Wang Hui,Wang Jun-Chuan,Wu Xiang-Feng,Pan Cheng-Si,Liu Lei,Yang Lin-Lin

Fe-based MOFs (Fe-MOFs) are excellent photocatalysts and have synergy well with Fenton reagents relative to other MOFs. In this work, a series of uniformly covered NH 2 -Fe-MIL-88B@TpPa-1-COF composites were synthesized using an in-situ anchoring growth strategy, which used F127 as functional molecule to decorate NH 2 -Fe-MIL-88B nanoparticles to eliminate their surface electrostatic repulsion with Tp molecules during the subsequent coating procedure. Meanwhile, the -NH 2 groups in the skeleton of NH 2 -Fe-MIL-88B could also be used as anchors to covalently connect TpPa-1-COF shell and migration channels for effective charge transfer. This uniformly covered core–shell structure would endow these composites with much more contact area and imine bond linkage between the Fe-MOFs core and COFs shell. Compared with the random packing structure, the uniformly covered Fe-MOF@COF-3 composite possessed a higher proportion of Fe 2+ to Fe 3+ . As a result, the optimized Fe-MOF@COF-3 catalyst could achieve the highest photo-Fenton degradation efficiency of 93.9% for tetracycline hydrochloride (TC⋅HCl), which was much higher than 54.8% of pure NH 2 -Fe-MIL-88B. In addition, the uniform TpPa-1-COF shell could further effectively enhance the stability of NH 2 -Fe-MIL-88B by protecting Fe ions from leaching, and the toxicity of the water samples treated with our photo-Fenton degradation process declined obviously. All these merits will endow Fe-MOF@COF-3 photo-Fenton catalyst great potential application value as in the field of environmental governance.

A chemiluminescence metalloimmunoassay for sensitive detection of alpha-fetoprotein in human serum using Fe-MIL-88B-NH2 as a label

Jingrong Zhou,Zhou Long,Yunfei Tian,Xiaodong Ding,Lan Wu,Xiandeng Hou