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Enhanced Photoreduction of Chromium(VI) Intercalated Ion Exchange in BiOBr <sub/>0.75</sub> I <sub/>0.25</sub> Layers Structure by Bulk Charge Transfer
摘要： Owing to its low separating and utilizing efficiency of photo-generated charges in the bulk, the application of photocatalytic technique has been restricted for decades. In this paper, based on interlayer ion-exchange between BiOBr0.75I0.25 layers, we demonstrated a specific interfacial process of photocatalytic Cr(VI) reduction by a direct bulk-charge transfer. The results showed that Cr(VI) was effectively converted to nontoxic Cr(III), even under neutral conditions (pH = 7.0). According to ultraviolet-visible spectroscopy (UV-Vis), X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis, the CrO4 2? anion was readily intercalated into the anion lattice layer of BiOBr0.75I0.25 by ion-exchange with OH? in the interlayer, forming a =Bi-O-CrO3 ? complex. Electron paramagnetic resonance (EPR) and photoelectron-chemistry measurements further revealed that excitation of =Bi-O- CrO3 ? by irradiation was crucial for photocatalytic detoxification of Cr(VI) under pH 7.0. The excitation of =Bi-O-CrO3 ? in BiOBr0.75I0.25 strengthened the bulk-charge transfer as follows: (i) electron transfer from O-II to CrVI produced CrV and O-I, respectively, via ligand-to-metal charge transfer excitation; and (ii) electron injection from BiOBr0.75I0.25 to [=Bi-O?I-CrVO3 ?]* (or exportation hole to valence band) resulted in the reduction of Cr(V) to Cr(III). After that, the newly formed Cr(III) in the interlayer of BiOBr0.75I0.25 was de-intercalated into solution due to the space charge repulsion between Cr3+ and Bi2O2 2+ slab, resulting in stable Cr(VI) reduction performance in a wide pH range from 2.0 to 7.0.
关键词： Bulk-charge transfer,Intercalated ion-exchange,De-intercalation,Photocatalytic reduction
更新于2025-09-23 15:23:52
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Development of Ion Exchange Ligands with High Separation Performance and Colorimetric Analysis Using Gold Nanoparticles Decorated with The Functional Ligands
摘要： Development of metal separating reagents with high selectivity is necessary for efficient separation and recovery of valuable metals contained in industrial wastes, and removal and detection of toxic metals. We have developed novel metal separating ligands with a diglycolamic acid (DGAA) framework. The ligands have a tridentate coordination structure consisting of an amide group and a carboxy group connected by an ether chain and provide a metal separation ability superior to that of commercial ligands. Since the ligands can be synthesized simply in one step, this helps to reduce the production costs of the ligands. In the present review article, we report the extraction characteristics of DGAA-type ligand for 56 kinds of metal ions, extraction separation of rare-earth metal ions, and removal of toxic metal ions. Furthermore, a one-pot biological approach to fabricate DGAA-decorated gold nanoparticles has been developed using the DGAA-type ligand fused to the N-terminus of a gold-binding peptide. It was found that the DGAA-decorated gold nanoparticles can act as a high-sensitive colorimetric sensor for detecting toxic metal ions with color change.
关键词： Ion-exchange materials,Gold nanoparticles,Diglycolamic acid,Colorimetric detection,Metal separating reagents,Separation and recovery
更新于2025-09-23 15:22:29
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Amplified and Multicolor Emission from Films and Interfacial Layers of Lead Halide Perovskite Nanocrystals
摘要： Lead halide perovskites are promising for energy harvesting and lighting applications. We show amplified emission from films of organic-inorganic or all inorganic lead halide perovskite nanocrystals. Also, multicolor emission is detected from interfacial layers of chloride and bromide perovskites. While amplified emission originates from spatial confinement of manifold charge carriers in films, multicolor emission emanates from interfacial ion exchanged layers. In a film, the amplified emission is averaged over a large number of nanocrystals, which prevents us from detecting any spectral narrowing. Conversely, amplified spontaneous emission (ASE) and spectral narrowing are detected from an isolated perovskite microcrystal. Interestingly, under low intensity excitation, a perovskite nanocrystal film shows unusually delayed emission, which becomes extremely fast and spatially confined at higher intensities of excitation light. By precisely detecting photoluminescence from an irradiated area and outside, we reveal the migration as well as confinement of photogenerated charge carriers in the film. The migration of charge carriers is more efficient in a film of organic-inorganic perovskites than all-inorganic perovskites.
关键词： spatial confinement,multicolor emission,interfacial ion exchange,amplified emission,Lead halide perovskites,charge carriers
更新于2025-09-23 15:21:01
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Kinetics of Ion-Exchange Reactions in Hybrid Organic-Inorganic Perovskite Thin Films Studied by In Situ Real-Time X-ray Scattering
摘要： The exchange of ions in hybrid organic-inorganic perovskites with the general formula APbX3 (A = MA, FA; X = I, Cl, Br) is studied in five different systems using in situ real-time grazing incident X-ray diffraction (GIXD). In systems where the organic cation is exchanged, we find a continuous shift of the lattice parameter. The relative shift compared to the pure materials is used to quantify the exchange. Whether or not a conversion is possible, as well as the amount of exchanged cations, depends on the halide used. In the case of the interconversion of MAPbI3 and MAPbCl3, we observe a decay of the diffraction peaks of the original perovskite and the emergence of new peaks corresponding to the structure with the alternative halide. Moreover, we determined the relevant time scales of the growth and decay of the perovskite structures.
关键词： ion-exchange reactions,kinetics,in situ real-time X-ray scattering,thin films,hybrid organic-inorganic perovskites
更新于2025-09-23 15:21:01
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Ion Exchange/Insertion Reactions for Fabrication of Efficient Methylammonium Tin Iodide Perovskite Solar Cells
摘要： The low toxicity, narrow bandgaps, and high charge-carrier mobilities make tin perovskites the most promising light absorbers for low-cost perovskite solar cells (PSCs). However, the development of the Sn-based PSCs is seriously hampered by the critical issues of poor stability and low power conversion efficiency (PCE) due to the facile oxidation of Sn2+ to Sn4+ and poor film formability of the perovskite films. Herein, a synthetic strategy is developed for the fabrication of methylammonium tin iodide (MASnI3) film via ion exchange/insertion reactions between solid-state SnF2 and gaseous methylammonium iodide. In this way, the nucleation and crystallization of MASnI3 can be well controlled, and a highly uniform pinhole-free MASnI3 perovskite film is obtained. More importantly, the detrimental oxidation can be effectively suppressed in the resulting MASnI3 film due to the presence of a large amount of remaining SnF2. This high-quality perovskite film enables the realization of a PCE of 7.78%, which is among the highest values reported for the MASnI3-based solar cells. Moreover, the MASnI3 solar cells exhibit high reproducibility and good stability. This method provides new opportunities for the fabrication of low-cost and lead-free tin-based halide perovskite solar cells.
关键词： ion exchange/insertion reaction,solar cells,crystal growth,lead-free perovskites
更新于2025-09-23 15:19:57
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Bi-component synergic effect in lily-like CdS/Cu <sub/>7</sub> S <sub/>4</sub> QDs for dye degradation
摘要： CdS has attracted extensive attention in the photocatalytic degradation of wastewater due to its relatively narrow bandgap and various microstructures. Previous reports have focused on CdS coupled with other semiconductors to reduce the photocorrosion and improve the photocatalytic performance. Herein, a 3D hierarchical CdS/Cu7S4 nanostructure was synthesized by cation exchange using lily-like CdS as template. The heterojunction material completely inherits the special skeleton of the template material and optimizes the nano-scale morphology, and achieves the transformation from nanometer structure to quantum dots (QDs). The introduction of Cu ions not only tuned the band gap of the composites to promote the utilization of solar photons, more importantly, Fenton-like catalysis was combined into the degradation process. Compared with the experiments of organic dye degradation under different illumination conditions, the degradability of the CdS/Cu7S4 QDs is greatly superior to pure CdS. Therefore, the constructed CdS/Cu7S4 QDs further realized the optimization of degradation performance by the synergic effect of photo-catalysis and Fenton-like catalysis.
关键词： Fenton-like catalysis,photocatalysis,CdS/Cu7S4,ion exchange,quantum dots,dye degradation
更新于2025-09-19 17:15:36
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Raman spectroscopic analysis of high molecular weight proteins in solution – considerations for sample analysis and data pre-processing
摘要： This study explores the potential of Raman spectroscopy, coupled with multivariate regression techniques and a protein separation technique (ion exchange chromatography), to quantitatively monitor diagnostically relevant changes in high molecular weight proteins in liquid plasma. Measurement protocols to detect the imbalances in plasma proteins as an indicator of various diseases using Raman spectroscopy are optimised, such that strategic clinical applications for early stage disease diagnostics can be evaluated. In a simulated plasma protein mixture, concentrations of two proteins of identified diagnostic potential (albumin and fibrinogen) were systematically varied within physiologically relevant ranges. Scattering from the poorly soluble fibrinogen fraction is identified as a significant impediment to the accuracy of measurement of mixed proteins in solution, although careful consideration of pre-processing methods allows construction of an accurate multivariate regression prediction model for detecting subtle changes in the protein concentration. Furthermore, ion exchange chromatography is utilised to separate fibrinogen from the rest of the proteins and mild sonication is used to improve the dispersion and therefore quality of the prediction. The proposed approach can be expeditiously employed for early detection of pathological disorders associated with high or low plasma/serum proteins.
关键词： sonication,pre-processing,disease diagnostics,Raman spectroscopy,plasma proteins,ion exchange chromatography,multivariate regression
更新于2025-09-19 17:15:36
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Ion Transport in Laser-Induced Graphene Cation-Exchange Membrane Hybrids
摘要： Ion exchange membranes hybridized with laser-induced graphene (LIG) might lead to membranes with functional surface effects such as antifouling, antibacterial or joule heating, however, understanding the change in the electrical properties of the membrane is essential. Here we studied LIG-modified ion-exchange polymeric membranes using electrochemical impedance spectroscopy (EIS). The conductivity of the anionic sulfonated polyethersulfone membranes and the effective capacitance of the membrane-electrolyte interface were obtained by fitting the EIS spectra to an electrochemical equivalent circuit and compared to LIG-modified non-ionic polyethersulfone films. The transport selectivity (as relative permeability) of counter-ions (K+, Na+, Mg2+, Ca2+) across the membrane was quantified using the membrane’s conductivities obtained from the EIS measurements. The total ohmic resistance of the membrane was directly correlated to the polymer thickness, (with negligible contribution from the conductive LIG layer), thereby establishing EIS as a rapid, low-cost and non-invasive method to accurately probe substrate usage in LIG modification.
关键词： laser-induced graphene,electrochemical impedance spectroscopy,capacitance,ion exchange membranes,conductivity,ion transport
更新于2025-09-16 10:30:52
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Low-loss Multimode Glass Waveguides with Beam-Expanded Fiber Connectors Enabling On-Board Optical Links
摘要： Ion-exchange glass waveguides are a very promising technology with a balanced trade-off between optical loss, integration density and fabrication costs. Graded-index multimode waveguides show low propagation loss of only 0.035 dB/cm at wavelength of 1310 nm in glass compatible with large scale manufacturing. For fiber cable connectivity, expanded beam connectors were used to terminate the waveguides by passive pick-and-place assembly, resulting in a coupling loss of ~1 dB per interface. Design and fabrication of glass waveguides are studied, and two-meter-long spiral waveguides along with 12 x 12 optical shuffle waveguide layouts made on a 9” x 12” area glass sheet are demonstrated experimentally.
关键词： Lensed Connector,Glass,Electro-Optical PCB,Optical Interconnect,Ion-exchange
更新于2025-09-12 10:27:22
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Unveiling the guest effect of N-butylammonium iodide towards efficient and stable 2D-3D perovskite solar cells through sequential deposition process
摘要： Improving the stability of hybrid organic-inorganic halide perovskite materials is urgent and essential for their applications in optoelectronic devices. Here, we introduce n-butylammonium iodide (BAI) into lead-iodide crystals as guest molecules. As a result of guest effect, only a small amount BA2PbI4 two-dimensional (2D) perovskite (n=1) is formed in PbI2-BAI films. Most of BAI crystals efficiently cut and squeeze the lattice network of lead iodide. The better orientation of 2D lead iodide crystals is obtained via this guest effect. In the following sequential deposition process, that BAI re-dissolve in MAI isopropanol (IPA) solution leads to a mesoporous structure of PbI2 and introduces a 2D perovskite (n=2) protect layer in 3D MAPbI3 after annealing. Finally, the morphology, crystallization and stability of CH3NH3PbI3 are simultaneously improved by the insertion of BAI guest molecules. Consequently, CH3NH3PbI3 PSCs with an optimized cutting behavior exhibited a power conversion efficiency of 18% and significantly improved the stability.
关键词： Ion exchange,Guest effect,2D-3D perovskite,Stability,Lattice compression,Sequential deposition
更新于2025-09-11 14:15:04