查找使用阿拉丁产品的科研文献

A three-channel colorimetric sensor array utilizing various Fe-MOFs for simultaneous discrimination of multiple pesticides

Ying Huang,Tiantian Liu,Ying Xiong,Qian Wen,Wang Li,Jiali Ren,Haiyan Zhong

The rapid discrimination and detection of pesticide residues represent a critical strategy for mitigating food safety risks associated with pesticide contamination. We designed and synthesized three distinct iron-based metal-organic frameworks (Fe-MOFs) nanozymes incorporating varied organic ligands. Owing to the differential modulation of their peroxidase-like activity by different pesticides, a facile yet efficient three-channel sensing array was constructed using these Fe-MOF nanozymes, allowing for the simultaneous discrimination of five pesticides (the minimum distinguishable concentration was 1 μg/mL). By converting pesticide-specific response signals into fingerprint profiles and subjecting them to analysis, including linear discriminant analysis and hierarchical cluster analysis, we achieved the classification of diverse pesticide species. Notably, the sensing platform exhibited good discriminative capability even for complex pesticide mixtures and real samples (corn and oat). This approach established a reliable and efficient strategy for pesticide screening, offering significant potential for enhancing food safety monitoring and safeguarding public health.

Temperature-Induced Structural Phase Transitions in Nano-Fe-Modified Sustainable Biochar for Efficient Sb(III) Adsorption

Z-scheme heterojunction WO3/BiOBr supported-single Fe atom for ciprofloxacin degradation via visible-light photocatalysis

Qinqin Yu,Youzhi Dai,Yulin Ling,Qian Wu,Zhu Zhang,Bo Feng

Single-atom catalysts have drawn tremendous attention on account of their high activity, selectivity and stability. Z-scheme heterojunctions can effectively improve the utilization of optical energy due to the enhanced separation of photogenerated electrons and holes. In this work, several catalysts associated with single-atom Fe (FeSA) loaded on Z-scheme heterojunction WO 3 /BiOBr were prepared; their structure, morphology and photoelectric properties were analyzed; their photocatalytic degradation performance of Ciprofloxacin (CIP) was investigated; and the effects of initial pH, initial CIP concentration, catalyst dosage, light intensity , inorganic anions and humic acid on CIP removal rate were examined. Relevant results showed that the percentage of CIP removal by FeSA/WO 3 /BiOBr could reach 98.5% (120 min); the optimal conditions were pH= 9, [CIP] 0 = 10 mg/L, [FeSA] 0 = 0.8 g/L and I light = 500 W (100% degradation rate within 30 min);·O 2 - and h + were the key active species. Results of the cyclic experiments suggested good stability of the catalyst. Furthermore, the mechanism of CIP photocatalytic degradation was proposed to be a synergistic mechanism of Z-scheme heterojunction migration and valence cycling between single-atom Fe 2+ and Fe 3+ . Finally, the products and pathways of CIP degradation were analyzed.

Electric field-temperature phase diagram of Bi1/2(Na0.8K0.2)1/2TiO3 relaxor ferroelectrics with Fe doping

Zhang Huazhang,Zhou Jing,Shen Jie,Yang Xiong,Wang Tianheng,Xiang Guanglei,Wei Quan,Chen Wen

Electrically and thermally induced transitions between ferroelectric and relaxor states are of great importance for Bi 1/2 Na 1/2 TiO 3 (BNT)-based materials because of their close relevance to electromechanical properties. In this study, the electric field-temperature ( E - T ) phase diagrams of Fe doped Bi 1/2 (Na 0.8 K 0.2 ) 1/2 TiO 3 (BNKT) ceramics are constructed via an experiment and theory combined approach. A novel phenomenological model based on the Landau-Devonshire theory and the Preisach model is proposed to describe the electric field induced phase transitions. Using this model, an approximate free-energy landscape is obtained by fitting the experimental double polarization-electric field loop, and then the electric field representing ferroelectric and relaxor two-phase equilibrium is calculated from the free-energy landscape for the construction of an E - T phase diagram. The constructed E - T phase diagrams meet basic thermodynamics requirements, for example, the Clausius-Clapeyron relation, and, therefore, overcome some of the shortcomings of previously reported E - T phase diagrams for BNT-based ceramics. The relationship between the E - T phase diagram and electromechanical properties is also established. From the E - T phase diagrams, it is predicted that Fe doping could lower the threshold field of triggering giant strains of BNKT ceramics at a high temperature. This prediction is successfully verified by experimental measurement of the electric field induced strain. At the optimized temperature for strain property, the threshold field of triggering giant strain is estimated to be about 2.6 kV/mm for a 3.0% Fe doped sample, significantly lower than 3.5 kV/mm for the undoped sample. This shows that the E - T phase diagram can provide valuable guidance for the improvement of electromechanical properties of BNT-based ceramics.

Effect of Fe, Co and Ni promoters on MoS2 based catalysts for chemoselective hydrogenation of nitroarenes

Wenpeng Han,Shanmin Wang,Xuekuan Li,Ben Ma,Mingxian Du,Ligong Zhou,Ying Yang,Ye Zhang,Hui Ge

The effect of Fe, Co and Ni promoters on supported MoS2 catalysts for hydrogenation of nitroarenes were systematically investigated via experiment, characterization and DFT calculation. It was found that the addition of promoters remarkably improved the reaction activity in a sequence of Ni > Co > Fe > Mo. Meanwhile Ni promoted catalyst with the best performance showed good recyclability and chemoselectivity for a wide substrate scope. The characterization results revealed that the addition of promoters decreased the interaction between Mo and support and facilitated the reductive sulfidation of Mo species to produce more coordinated unsaturated sites (CUS). DFT calculations showed that the addition of promoters increased the formation of CUS, and enhanced the adsorption of hydrogen. The influence degree of promoters followed the sequence Ni > Co > Fe > Mo, which was consistent with those of the activities. Nitrobenzene hydrogenation and hydrogen activation occurred at the S and Mo edge, respectively. The adsorbed hydrogen diffused from the Mo edge to the S edge to participate in the hydrogenation reaction. Mechanism investigation showed that the main reason for increased activity by the addition of promoters was the increase of amounts of CUS and the secondary reason was the augmentation of intrinsic activity of CUS. The present studies give a new understanding for promoter modified MoS2 catalysts applied for hydrogenation of nitroarenes.

Effect of Ni/Fe ratio on activation sintering and mechanical properties of molybdenum nickel iron alloy

Liu Jun-ru,Li Zhi-bo,Chen Ben,Chou Kuo-chih,Zhang Guo-hua

In order to improve the low ductility of the Mo-Ni alloy, Fe is added and the effects of Ni/Fe mass ratio on the densification behavior, microstructure evolution and mechanical properties of alloy were investigated. The experimental results show that when iron is added to 95Mo-5Ni alloy, the formation of brittle intermetallic phase δ -MoNi at the grain boundary is avoided. Meanwhile, the grain growth of Mo is also effectively inhibited in the sintering process. However, the addition of iron reduces the degree of densification of alloy since the activation effect of Ni is superior to that of Fe. From the experimental results, it could be concluded that the maximum hardness and bending strength are achieved by 95Mo-1.5Ni-3.5Fe alloy, which are HV 614 and 741 MPa, respectively. Combined with the analyses of bending fracture mechanism, the improvement relative to Mo-Ni alloy is likely attributed to the inhibition of the brittle phase.

Robust Fe-N4-C6O2 single atom sites for efficient PMS activation and enhanced FeIV = O reactivity

Chen Tiantian,Zhang Ganbing,Sun Hongwei,Hua Yetong,Yang Shu,Zhou Dandan,Di Haoxin,Xiong Yiling,Hou Shenghuai,Xu Hui,Zhang Lizhi

The microenvironment regulation of Fe-N 4 single atom catalysts (SACs) critically governs peroxymonosulfate (PMS) activation. Although conventional heteroatom substitution in primary coordination enhances activity, it disrupts Fe-N 4 symmetry and compromises stability. Herein, we propose oxygen doping in the secondary coordination shell to construct Fe-N 4 -C 6 O 2 SAC, which amplifies the localized electric field while preserving the pristine coordination symmetry, thus trading off its activity and stability. This approach suppresses Fe-N bond structural deformation (bond amplitude reduced from 0.875–3.175 Å to 0.925–2.975 Å) during PMS activation by lowering Fe center electron density to strengthen Fe-N bond, achieving extended catalytic durability (>240 h). Simultaneously, the weakened coordination field lowers the Fe=O σ* orbital energy, promoting electrophilic σ-attack of high-valent iron-oxo towards bisphenol A, and increasing its degradation rate by 41.6-fold. This work demonstrates secondary coordination engineering as a viable strategy to resolve the activity-stability trade-off in SAC design, offering promising perspectives for developing environmental catalysts.

Regulating N-doped biochar with Fe-Mo heterojunctions as cathode in long-life zinc-air battery

Xiao-ru Meng,Shuai Gao,Nianxi Liu,Pei-dong Wu,Zhen Fang

Carbonaceous electrode loaded nano Mo 2 C-Fe 3 N@NCF was synthesized by solvothermal and pyrolysis from soybean straw for high-performance zinc-air batteries (ZABs). The empowered ZAB achieved 1.51 V open-circuit voltage, 88.40 mW cm −2 power density and over 1150 h cycle life. Density functional theory analysis indicates that charge transfer from Mo 2 C-Fe 3 N heterogeneous structure to N-doped biochar can significantly reduce the reaction barrier for oxygen reduction/evolution reactions, enhancing the adsorption of oxygen intermediates. Cellulose-derived carbon provides a large specific surface area, and N-doping enhances the conductivity of the resultant biochar, which both play a crucial role in the efficient loading of Fe and Mo active sites. This work inspires the design and application of interfacial engineering on low-cost biochar carriers.

S2−-modified Hetero MOF-on-MOF of Ni-MOF/Fe-MOF with Efficient Seawater Oxidation Performance

Haifeng Ru,Yanji Bao,Yifeng Wang,Xiaohong Wang,Jinchun Tu,Qiang Wu,Yi Li,Lei Ding

Direct seawater electrolysis offers a viable solution to the excessive consumption of fresh water resources in existing industrial electrolytic water processes. However, electrolysis efficiency and material stability are affected by electrode material corrosion caused by chlorine evolution reactions (CER) at the anode positions. In this study, the prepared S-Ni-MOF/Fe-MOF material exhibits an exceptional performance in the oxygen evolution reaction (OER) both in alkaline solution and seawater. Specifically, the material achieves low overpotentials of 281 and 279   mV in 1.0   M KOH and alkaline seawater at 100   mA   cm −2 current density, and maintains stability for at least 100   h in both electrolyte solutions. The electronic structure of MOF-on-MOF was modulated through the introduction of S 2− , which induced a large number of vacancies. Furthermore, the reconstruction process on the material surface was accelerated by the formation of NiOOH and FeOOH, that served as protective layers and prevented the corrosion of the electrode material by Cl − , thereby enhancing its stability in seawater. Furthermore, computational studies have indicated that the Fe-Ni active sites at the heterointerface exhibit a synergistic effect, which has been confirmed by density functional theory (DFT) calculations. These results prove that this combination significantly reduces the energy barrier associated with the OER. Consequently, the reaction process is accelerated.

Room-temperature synthesis of Fe/Cu-BTC for effective removal of tetracycline antibiotic from aquatic environments

Wei Xiang,Yueting Liao,Jinwei Cui,Yangyang Fang,Bining Jiao,Xuesu Su

Antibiotic adsorbents are getting significant attention due to the hazards posed by the accumulation of tetracycline antibiotics in water, which can adversely impact human and environmental health. Bimetallic organic frameworks (BMOFs) exhibit considerable potential in adsorption owing to their dense pore structures and synergistic effects. However, synthesizing efficient, low-cost, and easy-to-prepare BMOFs faces several challenges. Here, we describe the practical synthesis of a series of Fe/Cu-bimetallic organic frameworks (Fe/Cu-MOFs) using simple room-temperature aqueous solvent methods. The pore size structure of Fe/Cu-MOFs is determined by the Fe/Cu ratio employed in the synthesis process. Remarkably, when the Fe/Cu molar ratio was 1:2, the void ratio of Fe/Cu-MOFs increased to 0.7326 cm 3 /g, with a predominant mesoporous structure, and the maximum tetracycline (TC) adsorption capacity exhibited by Fe/Cu-BTC-1/2 was reported at a Q max of 1130.23 mg/g. The adsorption kinetics followed the quasi-second-order kinetic model, and the adsorption isotherms were consistent. The Fe/Cu-BTC-1/2 was effective throughout a wide pH range (6.0–10.0), exhibiting resilience against ionic interference and enabling recycling. The predominant mechanisms of TC adsorption by Fe/Cu-BTC-1/2 include coordination, vacancy filling, and π-π stacking. Thus, our research provides an excellent adsorbent for TC antibiotics and novel insights into the simple synthesis of BMOFs and their application in environmental remediation.

Roughing Nitrogen-Doped Carbon Nanosheets for Loading of Monatomic Fe and Electroreduction of CO2 to CO

Yuxuan Liu,Yufan Tan,Keyi Zhang,Tianqi Guo,Yao Zhu,Ting Cao,Haiyang Lv,Junpeng Zhu,Ze Gao,Su Zhang,Zheng Liu,Juzhe Liu

The catalyst is the pivotal component in CO2electroreduction systems for converting CO2into valuable products. Carbon-based single-atom materials (CSAMs) have emerged as promising catalyst candidates due to their low cost and high atomic utilization efficiency. The rational design of the morphology and microstructure of such materials is desirable but poses a challenge. Here, we employed different Mg(OH)2templates to guide the fabrication of two kinds of amorphous nitrogen-doped carbon nanosheet-supported Fe single atoms (FeSNC) with rough and flat surface structures. In comparison to flat FeSNC with saturated FeN4sites, the rough FeSNC (R-FeSNC) exhibited unsaturated FeN4−xsites and contracted Fe-N bond length. The featured structure endowed R-FeSNC with superior capacity of catalyzing CO2reduction reaction, achieving an exceptional CO selectivity with Faradaic efficiency of 93% at a potential of −0.66 V vs. RHE. This study offers valuable insights into the design of CSAMs and provides a perspective for gaining a deeper understanding of their activity origins.

Stirred-electrodeposition construction of porous Fe-doped NiSe nanoclusters as a bifunctional catalyst for water splitting

Dingdiao Mo,Jiaxing Zhang,Guoxiang Chen,Zihao Huang,Xiangao Liu,Weitong Cai,Jie Cui,Wei Su

The electrodeposition method is commonly used for fabricating water splitting catalysts. Traditional methods assume a static precursor solution, ignoring the effects of solution dynamics. We theorized that stirring the solution during electrodeposition could improve mass transfer and current distribution, thereby enhancing electrochemical kinetics and nucleation. Consequently, we developed a novel electrodeposition technique to synthesize Fe-doped NiSe, an effective catalyst for alkaline water hydrolysis, demonstrating exceptional performance and stability. This catalyst notably decreases the overpotentials for OER and HER to 185/266 mV and 101/271 mV at 10 and 300 mA cm −2 , respectively. At the same time, the overall water splitting system comprising this catalyst requires only a low potential of 1.48 V to stably catalyze water splitting for over 60 hours. Electrochemical tests indicate that stirred deposition endows the catalyst with a larger electrochemically active area. In-situ Raman spectroscopy reveals NiOOH as an active phase, and Fe doping facilitates NiOOH formation at lower overpotentials, enhancing OER performance. First-principles calculations suggest that Fe doping optimizes the rate-determining step, lowers the activation energy for the OER process, and boosts conductivity. This study presents a method to improve OER efficiency in Ni-based catalysts, offering insights into mechanism control.