Co-precipitation Strategy Research Articles

Enhanced electrochemical activity by NiCo-P nano-particles modified Co-MOF nanorods

The design and preparation of high-performance electrode materials are among the most extensively researched topics in supercapacitor studies. By combining the three-dimensional structure and compatibility of cobalt-based metal-organic framework (Co-MOF) with the high redox activity of metal phosphates, a green, efficient, and safe co-precipitation and electro-deposition strategy was employed to fabricate the Co-MOF@NiCo-P heterostructure composite electrode material, with NiCo-P nanoparticles uniformly decorated on the surface of Co-MOF, addressing the issues of limited conductivity of Co-MOF and the tendency of NiCo-P to aggregate when grown in situ on foam nickel. In a three-electrode system, the Co-MOF@NiCo-P electrode exhibits specific capacities of 1389.8 F g−1 at 1 A g−1 and 964.3 F g−1 at 20 A g−1. The assembled Co-MOF@NiCo-P//AC hybrid supercapacitor device demonstrates energy densities of 54.08 Wh kg−1 (22.92 Wh kg−1) and power densities of 825 W kg−1 (8250 W kg−1), showing promising application prospects. This research offers a novel method for developing high-performance electrode materials.

Ideal Co-NiO solid solution with excellent low-temperature propene catalytic combustion performance

Doping engineering of transitional metal oxides offers a great opportunity to further optimize the performance of corresponding catalysts. Here, we presented a solid-state co-precipitation routine to synthesize the Co-NiO ideal solid solution, where Co atoms achieved nearly atomically isolation in the NiO lattice matrix. Remarkably a clear correlation was established between the reactivity for propene combustion and the Co dopant amounts, with the propene combustion rate increasing proportionally to the Co dopant amounts. The homogeneously dispersed Co single atoms or tiny CoOx nanoclusters ensure this linear relationship. More importantly, due to the emergence of Co single atoms and CoOx nanoclusters with a lower coordination number, significant propene adsorption and subsequent C = C bond dissociation were observed in this Co-doped NiO, which improved the propene combustion reaction rate. Therefore, this solid-state co-precipitation strategy provides an effective doping route for building an ideal doped solid solution.

CoFe2O4/carbon nitride Z-scheme heterojunction photocatalytic PMS activation for efficient tetracycline degradation: Accelerated electron transfer

The escalating consumption of antibiotics and their subsequent discharge into the water supply is a matter of significant concern. This study presents an innovative visible light (VL) activated peroxymonosulfate (PMS) system for efficient degradation of the targeted antibiotic tetracycline (TC). CoFe2O4/carbon nitride (CFO/CN) Z-scheme heterojunctions were designed and synthesized through a simple co-precipitation and calcination strategy. Surface and analytical techniques were employed to comprehensively characterize the prepared CFO/CN, demonstrating its enhanced efficiency in separating photoinduced charge carriers. CFO/CN exhibited a 27-fold enhancement in TC degradation rate constants with PMS under VL. The effects of various factors including catalyst dosage, PMS concentration, initial pH, and content of CFO on TC degradation efficiency were investigated. Reactive species quenching and EPR measurements revealed the main contribution of superoxide radicals (•O2−) made to TC degradation. TC degradation pathways were proposed based on oxidized product analysis. The assessment of acute toxicity demonstrated the reduced toxicity of the formed intermediates. A plausible mechanism for TC degradation over CFO/CN-PMS-VL was discussed. This work provides a comprehensive guide for heterojunction photocatalytic activation of PMS for efficient micropollutant degradation.

Tuning the local electronic structure of Co15V-ZIF through bimetallic synergies as a bifunctional electrocatalyst for overall water splitting

Co-based bimetallic zeolite imidazolate frameworks (ZIFs) have been shown as promising electrocatalysts for the oxygen evolution reaction, but their electronic structure’s influence on the catalytic performance for overall water splitting still needs further investigation. In this study, Co15V-ZIF, structured as two-dimensional (2D) nanosheet arrays, are grown on nickel foam using one-step co-precipitation strategy. Owing to the synergistic effects of vanadium (V) and cobalt (Co) reasonably regulating the electronic structure, the synthesized bimetallic ZIFs demonstrate superior catalytic performance, which required the overpotentials of only 227 and 68 mV to achieve a current density of 10 mA cm−2 in 1 M KOH for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively. Furthermore, the water electrolyzer assembled with bimetallic ZIF as cathode and anode exhibits the capability to achieve 10 mA cm−2 at a low cell voltage of 1.57 V. In situ Raman spectroscopy reveals that the introduction of V facilitates the formation of V-CoOOH, the real active site for OER, at lower applied potentials. Besides, it induces a local acidic environment on V-Co(OH)2, the real active sites, thereby enhancing the HER performance of the sample. Density Functional Theory (DFT) calculations further show that the synergistic effects of V and Co induce electron redistribution, thereby improving electrical conductivity, reducing the energy barrier for water dissociation and hydrogen adsorption, which promotes the formation of H3O+ and triggering H3O+-induced water reduction in alkaline media. This work provides new insight into tailoring electronic structures to rationally design highly efficient ZIF electrocatalysts.

Atomic-scale investigation on the mechanical behaviors of the γ′/γ′′ co-precipitates compounds in Ni-based superalloys

The γ′/γ′′ co-precipitation strategy entails excellent mechanical properties for Ni-based superalloys, but the deformation mechanism of γ′/γ′′ co-precipitates Ni-based superalloys at atomic-scale remains unclear. In this work, we studied the effect of loading rate, void size, and temperature on the mechanical behaviors of γ′-Ni3Nb/γ′′-Ni3Nb co-precipitates via molecular dynamic (MD) simulations. The simulation results show that the tensile load rate 1×109 s−1 is critical for the free-void γ′/γ′′ co-precipitates. When the loading rate exceeds 1×109 s−1, a transition occurs in the deformation mechanism, leading to a rapid increase in tensile strength and a subsequent reduction in flow stress until it eventually vanishes (1.35 GPa→0.98 GPa→0 GPa). The presence of voids at the interphase boundary significantly reduces the material's strength, with this weakening effect becoming more pronounced as the void radius increases. Furthermore, the voids facilitate the easier penetration of dislocations into the γ′ and γ′′ precipitated phases along the void peripheries through the interphase boundary. The study also reveals that the trends in Young’s modulus and yield stress for both pre-void and void-free models are similar with increasing temperature, with Young’s modulus decreasing as temperature rises. Notably, at elevated temperatures, γ′′ precipitated phase transitions occur within the γ′/γ′′ co-precipitates, and the yield stress is maximum at 800 K. This study provides valuable insights into the mechanical behavior of γ′/γ′′ co-precipitates and the weakening effects of atomic-scale voids in Ni-based superalloys.

Boosting adsorption of ciprofloxacin on Fe3O4 nanoparticles modified sepiolite composite synthesized via a vacuum-filtration assisted coprecipitation strategy

Treatment of antibiotics-containing wastewater is imperative for ensuring environmental and public health. However, effectively removing antibiotics in environment is still a great challenge. Fabrication of sepiolite-supported iron oxide nanomaterials with large specific surface area and high reactivity is a promising solution for efficient antibiotics removal. In this work, a highly dispersed Fe3O4 nanoparticle modified sepiolite composite (Fe3O4-sep-vacuum) was synthesized in-situ by employing a novel vacuum-filtration assisted coprecipitation strategy for the first time. Fe3O4-sep-vacuum exhibited the highest adsorption capacity to ciprofloxacin compared with those of pure Fe3O4 nanoparticles, sepiolite, and those composites obtained by traditional coprecipitation methods. Approximately 93 % of CIP (20 mg/L) could be removed by Fe3O4-sep-vacuum within 20 min at initial pH 6.0. The kinetic and adsorption isotherms followed pseudo-second-order and Temkin models, respectively. The maximum adsorption capacity (qm) of Fe3O4-sep-vacuum for CIP was 18.4 mg/g at initial pH 6.0. The solution pH, temperature, coexisting divalent cations, and HA concentration were demonstrated to play substantial roles in the adsorption processes of ciprofloxacin on Fe3O4-sep-vacuum surface. The Fe3O4-sep-vacuum maintained excellent stability and reusability during CIP adsorption process. Electrostatic interactions play a decisive role in the adsorption process of ciprofloxacin by Fe3O4-sep-vacuum. Hydrogen bonds and hydroxyl groups on the Fe3O4-sep-vacuum surface also play important roles in the adsorption process of ciprofloxacin. Fe3O4-sep-vacuum also exhibited excellent adsorption capacity to ofloxacin. These results indicate that the vacuum-filtration assisted coprecipitation strategy could be used to fabricate monodispersed nanoparticles modified sepiolite composites, which could be acted as promising materials for highly efficient remediating antibiotics contaminated wastewater.

Supremacy of l-glutamic acid on cerium doped ZnS nanoparticles for enhanced structural, morphological, optical properties and their applications in antimicrobial activity with efficient detection of latent fingerprints

The pure Zinc Sulphide (ZnS) and l-Glutamic acid capped Cerium doped Zinc Sulphide nanoparticles of different concentrations (0, 5, 10 & 15 mol %) was developed via a simple chemical co-precipitation strategy. l-Glutamic acid is the a minimum hazardous, non-essential amino acid group, and its capped properties are optimal for semiconducting nanoparticles that include ZnS. It also has a considerable effect on enhancing the structural, optical, and photoluminescent properties of Ce-doped ZnS nanoparticles. The produced nanoparticles were examined using X-ray diffraction (XRD), dynamic light scattering (DLS), Field emission scanning electron microscope (FESEM), Fourier transform Infrared spectroscopy (FT-IR), Photoluminescence (PL), and UV–Vis spectrometer. The XRD pattern revealed that all of the generated nanostructures have a cubic form with diffraction planes (111), (220), and (311), and the dimensions of the crystallite ranging from 1.685 nm to 2.144 nm. Its morphological view of nanoparticles was investigated utilizing FESEM. DLS testing demonstrated that the particle sizes were less than 30 nm. The functional groups of nanoparticles have been identified using FTIR investigations. PL investigations suggested the existence of substantial emission bands. The ultraviolet–visible scrutiny exhibited an optical band gap that spans 3.12–3.77 eV. The antimicrobial activity analysis was examined by the gram-positive and gram-negative bacteria in pure ZnS, l-glutamic acid-capped ZnS, and glutamic-capped 15 mol% Ce-doped ZnS, with their inhibitory zones also verified. Finally, it was ascertained that this type of nanoparticles was highly effective to reveal the fingerprints detection purposes in forensic applications.

Designing a novel electrochemical sensor based on Ni and Mg co-doped ZnO nanoparticles for the detection and quantification of cysteamine from bodily fluids

The current work reports a novel approach for the development of an electrochemical sensor based on Ni and Mg-co-doped ZnO nanoparticles (ZNMO) to detect and quantify cysteamine (CA). The chemical co-precipitation strategy was used to synthesize zinc oxide co-doped with magnesium and nickel which can be used as a catalyst material. FTIR, XRD, XPS, BET and SEM-EDX examinations were used to confirm the produced material. The surface of the glassy carbon electrode (GCE) was modified with ZNMO nanoparticles, resulting in a remarkable improvement in the surface area of the electrodes which in turn improved the response for CA compared to previously reported studies. This enhancement can be attributed to the superior catalytic activity of the material in electro-oxidizing CA. The electrochemical studies were carried out using the analytical techniques like cyclic voltammetry and differential pulse voltammetry using 0.1 M phosphate buffer saline as a supporting medium. This fabricated sensor, ZNMO nanoparticles modified GCE (ZNMO/GCE) has shown superior sensing characteristics, including high selectivity, sensitivity, stability, and repeatability, for the identification and quantification of CA. The sensor successfully confirmed the diffusion-controlled electrode technique. It exhibited the widest linear range, spanning from 1 nM to 2500 μM, which is the most impressive result ever reported. The limit of detection (LOD) was determined to be 0.75 nM. Additionally, at the developed sensor, a real-sample analysis was conducted using biological fluids. Hence, the fabricated ZNMO/GCE showed excellent electrocatalytic performance for CA sensing, making it suitable for real-time monitoring.

Magnetic, self-heating and superhydrophobic sponge decorated with BN and CoFe2O4 for high-efficient cleanup of crude oil spills using facile co-precipitation strategy

Accidents involving petrochemical spills have repeatedly threatened the security of the eco-environment. The leaked crude oil exhibits poor fluidity, low adsorption efficiency, and urgent issues such as potential fire risks that require immediate attention. Herein, a multifunctional superhydrophobic sponge Si@CFO@BN@PU was prepared by a simple co-precipitation strategy based on BN and CoFe2O4. The results demonstrate that Si@CFO@BN@PU exhibits excellent superhydrophobic properties, with a water contact angle of 162° and a slide angle of less than 10°, and oil adsorption capacity ranging from 32.3 to 68.4 g/g. Furthermore, the modified sponge also possesses certain magnetic properties, allowing Si@CFO@BN@PU to be moved on the water surface via an external magnetic field and effectively adsorb floating oil. Meanwhile, the modified sponge exhibits excellent photothermal properties. The whole sponge can be heated up to 80 °C in just 60 s under simulated sunlight conditions, effectively reducing the adsorption time of viscous oil by 90 %. Moreover, the cone calorimeter test results demonstrate excellent fire safety of Si@CFO@BN@PU even after adsorption of petroleum. The peak heat release rate (pHRR), total heat release (TSR), maximum CO release rate, and maximum CO2 release rate have decreased by 37.8 %, 23.3 %, 45.4 %, and 34.1 %, respectively. Therefore, Si@CFO@BN@PU is an effective, safe and sustainable new adsorbent material with a wide range of applications in treating petrochemical spills.

Aqueous cerium ion battery: A novel aqueous rechargeable battery

Aqueous rechargeable batteries (ARBs) are a potential energy storage system with lowcost aqueous electrolyte and high safety. Multivalent host carriers in electrolyte can offer a wider variety of valence states and redox properties leading to high capacity. In this work, an aqueous cerium ion aqueous (ACIBs) battery has been reported with a satisfactory electrochemical performance for the first time. By utilizing the advantages of stable structure and three-dimensional (3D) open framework of Prussian blue analogues (PBAs), the problem of cerium ions insertion/de-insertion into host materials due to high charge and large size can been successfully solved. Herein, the copper hexacyanoferrate (CuPBA) is prepared through a facile coprecipitation strategy as cathode material of ACIBs. The CuPBA cathode deliver a satisfactory capacity (79 mAh g−1 at 50 mA g−1) and an excellent cycling stability after long-time cycles (86.8 % capacity retention after 5000 cycles at 1000 mA g−1). As a result, the cathode material in ACIBs system displays excellent rate capability and cycling performance. The successful assemble of the full battery also verifies the feasibility of ACIBs. In addition, the energy storage mechanism of Ce3+ ion insertion/de-insertion process is explained by ex situ X-ray diffraction and X-ray photoelectron spectroscopy measurements. This work opens up a new direction and provides a foundation for development of novel ARBs.

Inhibiting the Jahn-Teller Effect of Manganese Hexacyanoferrate via Ni and Cu Codoping for Advanced Sodium-Ion Batteries.

Manganese (Mn)-based Prussian blue analogs (PBAs) are of great interest as a prospective cathode material for sodium-ion batteries (SIBs) due to their high redox potential, easy synthesis, and low cost. However, the Jahn-Teller effect and low electrical conductivity of Mn-based PBA cause poor structure stability and unsatisfactory performance during the cycling. Herein, a novel nickel- and copper-codoped K2Mn[Fe(CN)6] cathode is developed via a simple coprecipitation strategy. The doping elements improve the electrical conductivity of Mn-based PBA by reducing the bandgap, as well as suppress the Jahn-Teller effect by stabilizing the framework, as verified by the density functional theory calculations. Simultaneously, the substitution of sodium with potassium in the lattice is beneficial for filling vacancies in the PBA framework, leading to higher average operating voltages and superior structural stability. As a result, the as-prepared Mn-based cathode exhibits excellent reversible capacity (116.0 mAh g-1 at 0.01 A g-1) and superior cycling stability (81.8% capacity retention over 500 cycles at 0.1 A g-1). This work provides a profitable doping strategy to inhibit the Jahn-Teller structural deformation for designing stable cathode material of SIBs.

Construction of novel S-defects rich ZnCdS nanoparticles for synergistic visible light assisted photocatalytic degradation of rhodamine B: Insights into mechanism, pathway and by-products toxicity evaluation

The contamination of wastewater by azo dyes indicates serious environmental risks. Currently, industries worldwide use approximately 700,000 tons of these dyes annually, making their removal a significant challenge. In photocatalysis research, a prominent area of dedication to the advancement of visible light photocatalysis aims to achieve superior performance in overall activity. In this study, we fabricated ZnCdS nanoparticles (NPs) via a simple co-precipitation strategy, and sulphur (S)-defect-rich ZnCdS NPs (D-ZnCdS) were created through the ball milling method. These S-defect nanoparticle (NPs) catalysts were utilized for rhodamine B (RhB) dye photocatalytic degradation experiment. (XRD) X-ray diffractometer, X-ray photoelectron spectroscopy (XPS), surface-enhanced Raman spectroscopy, and photoluminescence (PL) spectroscopy characterization studies explained the induced S-defect rich in D-ZnCdS NPs. Further, the morphological, band gap determination, and photogenerated charge carrier recombination efficiency were studied using different analytical and spectroscopic characterization techniques. The Brunauer-emmett-teller (BET) results indicate the increased surface area of D-ZnCdS NPs thereby providing more active sites. The photocatalytic degrading efficiency of D-ZnCdS over RhB explains the complete degradation of pollutants within 260 min. This enhancement in the catalytic process is attributed to the increased absorption of photon energy from the visible light and large defect-rich active sites. Further, the involvement of hydroxyl (*OH) and superoxide radicals (O2*-) in the degradation of RhB along with the presence of sulphur defects, significantly improves the charge transfer in ZnCdS NPs. The involvement of certain factors like pH, ions, NCs catalyst and different RhB concentrations on RhB degradation was investigated. Additionally, D-ZnCdS NPs showed stable degrading capability even after six consecutive cycles of catalytic RhB degradation. The by products formed during the RhB photodegradation experiment were identified using Gas chromatography-mass spectrometer (GC-MS) analysis, and toxicity in fish, daphnia, and algae was examined using the Ecological structure-activity relationships (ECOSAR) program. From the above findings, the current research work provides a new strategy for utilizing defect-engineered D-ZnCdS NPs as a promising catalyst for various environmental remediation applications and paves a ways for manufacturing innovation.

Co-precipitation synthesis of carbonic anhydrase-embedded magnetic zeolitic imidazolate framework-8 nanocomposite enzyme for enzymatic CO2 conversion and utilization in facilitating uranium extraction

Carbonic anhydrase (CA)-mediated carbon conversion and utilization (CCU) technology is recognized as an eco-friendly and cost-effective strategy for carbon reduction. However, the broader application of this technology is significantly constrained by the operational instability and challenging recyclability of free CA. Fortunately, nano-integrated biocatalysis has emerged as an effective solution to these challenges. In this study, we immobilized CA for the first time as a CA-embedded ferriferous oxide-zeolite imidazolium framework-8 (Fe3O4@ZIF-8@CA) nanocomposite enzyme through a one-pot co-precipitation strategy, integrating both the in-situ growth of ZIF-8 around the Fe3O4 core and the immobilization of CA within a single step. Subsequently, this nanocomposite was employed as a nano-integrated biocatalyst to facilitate an innovative CCU pathway. This pathway leverages bicarbonate, produced from the enzymatic hydration of carbon dioxide (CO2), as a substantive uranyl complexing agent to facilitate the neutral leaching of sandstone uranium ore. Systematic characterization techniques, including SEM, TEM, XRD, FTIR, TGA, CLSM, and MPMS, confirmed that Fe3O4@ZIF-8@CA, which possesses a core–shell structure and excellent magnetic responsiveness, has been successfully synthesized. Enzymatic assays revealed that Fe3O4@ZIF-8@CA retains approximately 79% of the activity compared to its free counterparts while demonstrating significantly enhanced thermal and storage stability. The outcome of CO2 hydration conversion for facilitating uranium extraction indicated that, compared with the non-enzymatic reaction group, the bicarbonate yield increased up to 1.5 times, and the uranium extraction efficiency was nearly 10% higher in the Fe3O4@ZIF-8@CA-mediated reaction group. These findings suggest that Fe3O4@ZIF-8@CA possesses excellent catalytic properties for CO2 hydration and can achieve multiplied decarbonization by mediating this innovative CCU pathway. Furthermore, Fe3O4@ZIF-8@CA demonstrated superb reusability and durability, experiencing no significant degradation in its catalytic performance after eight consecutive hydration regeneration cycles. Our research is anticipated to be a viable option for advancing the goals of carbon neutrality and sustainable development.

Coprecipitation Strategy for Halide-Based Solid-State Electrolytes and Atmospheric-Dependent In Situ Analysis.

In the continuous pursuit of an energy-efficient alternative to the energy-intensive mechanochemical process, we developed a coprecipitation strategy for synthesizing halide-based solid-state electrolytes that warrant both structural control and commercial scalability. In this study, we propose a new coprecipitation approach to synthesized Li3InCl6, exhibiting both structural and electrochemical performance stability, with a high ionic conductivity of 1.42 × 10-3 S cm-1, comparable to that of traditionally prepared counterparts. Through the in situ synchrotron X-ray diffraction technique, we unveil the stability mechanisms and rapid chemical reactions of Li3InCl6 under dry Ar, dry O2, and high-humidity atmosphere, which were not previously reported. Furthermore, the fast reversibility capability of moisture-exposed Li3InCl6 was tracked under vacuum, revealing the optimal recovery conditions at low temperatures (150-200 °C). This work addresses the critical challenges in structural engineering and sustainable mass production and provides insights into chemical reactions under real-world conditions.

Copper-Modified Iron Oxide Nanoparticles: A Novel Catalyst for Effective Congo Red Dye Degradation in Wastewater Treatment

The raising worldwide water tainting from different sources has delivered admittance to unpolluted drinking water progressively testing. The release of effluents containing colors into water bodies become as a basic ecological worry lately. Regular treatment strategies are insufficient in wiping out these steady and risky poisons, requiring the investigation of novel methodologies. In this review, Cu-doped FeO nanoparticles were easily blended by using a co-precipitation strategy, and their synthetic qualities were entirely analyzed. These nanoparticles showed extraordinary adsorption abilities in the corruption of various color compounds. In particular, manufactured acidic color was focused on for expulsion utilizing metal-doped nanoparticles. Ideal boundaries for maximal acidic color not set in stone by surveying the adsorbent portion, beginning color focus, contact time, and temperature. The pH was distinguished as a critical variable, with the best incentive for maximal adsorption of Congo Red Dye viewed as less than 7. As indicated by late discoveries, Cu/FeO nanoparticles displayed unrivalled adsorption limit with regards to Congo Red Dye color at an ideal pH of 2, a measurement of 0.5 g/500 mL, a contact season of an hour and a half, and a color centralization of 150 ppm at 35° centigrade. Pseudo second order adsorption kinetic model exhibited amazing fitting outcomes for adsorption energy and balance information.

Novel existence of Mn and Cu in WO3 nanostructures for promising photocatalytic activity against MB dye and Levofloxacin antibiotic

To enhance photocatalytic degradation of MB dye and Levofloxacin antibiotic, facile coprecipitation strategy was used to synthesize pure WO3 and novel Mn-Cu codoped WO3 nanostructures. The synthesized nanostructures were probed by XRD, SEM, EDX, FTIR, XPS, BET, TEM, PL and UV–vis spectra to analyze optical and morphological properties. Pure WO3, Mn2%-Cu1%-WO3, Mn2%-Cu3%-WO3, Mn2%-Cu5%-WO3 and Mn2%-Cu7%-WO3 were optimized novel materials that were used for water treatment against model impurities. Optical properties of pure WO3 were enhanced to successfully increase the photocatalytic degradation of principal water pollutants. Over a time span of 175 minutes, 86.7% of MB dye was degraded and 75.9% Levofloxacin was degraded by an average of 49 nm and 2.16 eV bandgap Mn2%-Cu5%-WO3 optimal sample. Due to smaller particle size, surface to volume ratio gave more active sites to the photocatalysts for pollutants degradations. Interestingly, just 15% degradation loss was observed after consecutive 6 cycles against the degradation of MB dye and 9.1% loss against Levofloxacin medicine after 6 photocatalytic runs. XPS spectra offered crucial insights into the elemental composition and chemical states of the Mn-Cu-WO3 nanostructures. According to these findings, Mn-Cu-WO3 can be used as a good candidate with long time stability against pollutants degradations.

Novel green/red oxyfluoride phosphors with excellent optical properties for near-UV excited white light emitting diode

Novel eye-sensitive Ba3Nb2O2F12(H2O)2:Tb3+ green and Ba3Nb2O2F12(H2O)2:Mn4+ red oxyfluoride phosphors with extremely strong absorption in the UV region were designed and synthesized by simple co-precipitation strategy. Particularly, Tb3+ ions were doped in this matrix for the first time, which greatly improves their absorption efficiency in the near ultraviolet region (367 nm) and emits sharp green light (544 nm). In addition, the Ba3Nb2O2F12(H2O)2:Mn4+ red phosphors have strong zero phonon line (ZPL) emission at 625 nm, which is conducive to improving the sensitivity of human eye and color purity. Meanwhile, the optical properties of the red phosphor are significantly enhanced via doping K+ cations as charge compensators. Crystal field environment and nephelauxetic effect of the as-prepared phosphors before and after K+ cation doping were systematically analyzed. Moreover, these synthesized red/green phosphors have good thermal stability and moisture resistance. Remarkably, the as-prepared Ba3Nb2O2F12(H2O)2:5%Mn4+ or K0.9Ba2.1Nb2O2F12(H2O)2:5%Mn4+ red phosphors can be directly mixed with the as-synthesized Ba3Nb2O2F12(H2O)2:13%Tb3+ green phosphor coating on 365 nm near-ultraviolet LED chip to package WLED devices with excellent electroluminescence performance. These findings are conducive to opening an avenue for screening the unique structure of optical materials.

Integration of Ag2S QDs in 3D Zn3V2O8 nanoflower for visible light driven effective photocatalytic degradation of rifampicin: Insights into preparation, mechanism and by-product toxicity evaluation

Water contamination is regarded as one of the most important concerns in the last decade and its crucial to develop an efficient and productive technique to remediate organic pollutants from waters. Photocatalytic degradation processesare advanced oxidation procedure and a promising technique for the degradation of organic pollutants. In this study, we fabricated Ag2S/Zn3V2O8 nanocomposite (AS/ZVO NCs) for the degradation of rifampicin (RIF) by ultrasonicated co-precipitation strategy. The NCs was optimally synthesized with varying deposition concentrations, among which 5%-Ag2S/Zn3V2O8 (5%-AS/ZVO) exhibited superior photocatalytic activity (95.5%) under visible light irradiation. Moreover, the experiments were conducted at diverse operational parameters such as different NCs dosage, different concentration of RIF, pH, and ions, to investigate the impact on the photocatalytic degradation of RIF. Notably, XRD and XPS results of used 5%-AS/ZVO NCs demonstrated commendable stability and possess sustained integrity in structure after six consecutive cycle tests. The scavenging study and radical trapping experiments confirmed the formation of •OH and O2•- during photocatalytic reaction. The mechanism of photocatalytic degradation of RIF by 5%-AS/ZVO NCs was proposed and the pathway was predicted based on the GC-MS results. The current study provides a comprehensive understanding for designing efficient photocatalysts for the environmental remediation applications.

A rapid VEGF-gene-sequence photoluminescence detector for osteoarthritis.

Osteoarthritis (OA) has become a serious problem to the human society for years due to its high economic burden, disability, pain, and severe impact on the patient's lifestyle. The importance of current clinical imaging modalities in the assessment of the onset and progression of OA is well recognized by clinicians, but these modalities can only detect OA in the II stage with significant structural deterioration and clinical symptoms. Blood vessel formation induced by vascular endothelial growth factor (VEGF) occurs in the early stage and throughout the entire course of OA, enables VEGF relating gene sequence to act as a biomarker in the field of early diagnosis and monitoring of the disease. Here in, a facile rapid detection of VEGF relating ssDNA sequence was developed, in which manganese-based zeolitic imidazolate framework nanoparticles (Mn-ZIF-NPs) were synthesized by a simple coprecipitation strategy, followed by the introduction and surficial absorption of probe ssDNAs and the CRISPR/Cas12a system components. Furthermore, fluorescence experiments demonstrated that the biosensor displayed a low detection limit of 2.49nM, a good linear response to the target ssDNA ranging from 10nM to 500nM, and the ability of distinguishing single nucleotide polymorphism. This finding opens a new window for the feasible and rapid detection of ssDNA molecules for the early diagnose of OA.

Stereoselective reduction of diarylmethanones via a ketoreductase@metal-organic framework.

Mainly owing to their well-defined pore structures and high surface areas, metal-organic frameworks (MOFs) have recently become a versatile class of materials for enzyme immobilization. Nevertheless, most previous studies were focused on model enzymes such as cytochrome c, catalase, and glucose oxidase, with the application of MOF-derived biocomposites for (asymmetric) organic synthesis being rare. In the present work, the immobilization of the ketoreductase KmCR2 onto the zeolitic imidazolate framework (ZIF), a prominent type of MOF, was pursued using the controlled co-precipitation strategy, with a low 2-methylimidazole (2-mIM)/Zn molar ratio of 8 : 1 being employed. Such fabricated biocomposites denoted as KmCR2@ZIF were found to exist mainly in an amorphous phase, as suggested by the scanning electron microscopy (SEM) and powder X-ray diffraction (PXRD) data. Improved thermal and storage stabilities were observed for KmCR2@ZIF compared with the free enzyme. Stereoselective reduction of nine diarylmethanones 1 catalyzed by KmCR2@ZIF was performed, and the corresponding enantioenriched diarylmethanols 2 were afforded in 40-92% conversions with good to excellent optical purities (up to >99% ee). Critically, the current work demonstrated that the unique characteristic of KmCR2, namely the substituent position-controlled stereospecificity (meta versus para or ortho), was not altered upon the enzyme immobilization onto the ZIF.