Search

The rational design of the electronic structure and elemental compositions of anode electrocatalysts for formic acid electrooxidation reaction (FAOR) is paramount for realizing high‐performance direct formic acid fuel cells. Herein, palladium‐boride nanoflowers (Pd‐B NFs) with controllable boron content are rationally designed via a simple wet chemical reduction method, utilizing PdII‐dimethylglyoxime as precursor and NaBH4 as both reductant and boron source. The boron content of Pd‐B NFs can be regulated through manipulation of reaction time, accompanying with the crystal phase transition from face‐centered cubic to hexagonal close‐packed within the parent Pd lattice. The obtained Pd‐B NFs exhibit increased FAOR mass and specific activity with increasing boron content, showcasing remarkable inherent stability and anti‐poisoning capability compare to commercial Pd and platinum (Pt) nanocrystals. Notably, the sample reacted for 12 h reveals high FAOR specific activity (31.5 A m−2), which is approximately two times higher than the commercial Pd nanocrystals. Density functional theory calculations disclose that the d‐sp orbital hybridization between Pd and B modifies surface d‐band properties of Pd, thereby optimizing the adsorption of key intermediates and facilitating FAOR kinetics on the Pd surface. This study paves the way toward the utilization of metal boride‐based materials with simple synthesis methods for various electrocatalysis applications. [ABSTRACT FROM AUTHOR]

[Display omitted] Multicore flower-like iron oxide nanoparticles (IONPs) are among the best candidates for magnetic hyperthermia applications against cancers. However, they are rarely investigated in physiological environments and their efficacy against cancer cells has been even less studied. The combination of magnetic hyperthermia, using multicore IONPs, with selected bioactive molecules should lead to an enhanced activity against cancer cells. Multicore IONPs were synthesized by a seeded-growth thermal decomposition approach. Then, the cytotoxicity, cell uptake, and efficacy of the magnetic hyperthermia approach were studied with six cancer cell lines: PANC1 (pancreatic carcinoma), Mel202 (uveal melanoma), MCF7 (breast adenocarcinoma), MB231 (triple-negative breast cancer line), A549 (lung cancer), and HCT116 (colon cancer). Finally, IONPs were modified with a chemotherapeutic drug (SN38) and tumor suppressor microRNAs (miR-34a, miR-182, let-7b, and miR-137), to study their activity against cancer cells with and without combination with magnetic hyperthermia. Two types of multicore IONPs with very good heating abilities under magnetic stimulation have been prepared. Their concentration-dependent cytotoxicity and internalization have been established, showing a strong dependence on the cell line and the nanoparticle type. Magnetic hyperthermia causes significant cell death that is dramatically enhanced in combination with the bioactive molecules. [ABSTRACT FROM AUTHOR]

The use of loaded co-catalysts has been found to be effective in addressing the issue of rapid recombination of photogenerated carriers, which can limit photocatalytic efficiency. Herein, we report on the adsorption of Ni2+ on the surface of CdS by photodeposition to obtain NiS/CdS composites. It improves visible light response while providing abundant active sites for photocatalytic reaction. NiS/CdS exhibits a superior photocatalytic H 2 evolution rate of up to 7557 μmol·g−1·h−1, which is approximately 4.9 times higher than that of CdS. The corresponding AQE is 19.6% at 420 nm. XPS and photoelectrochemical testing provide a possible mechanism, indicating that the heterojunction between NiS and CdS promotes the transfer and separation of interfacial charge, thus accelerating the water decomposition reaction. This work demonstrates the effectiveness of loading two-dimensional thin film co-catalysts to design high-performance and low-cost composites for promoting the photocatalytic reaction. [Display omitted] • NiS film as co-catalyst is able to reduce the overpotential of hydrogen evolution reaction. • The heterojunction accelerates the transfer and separation of photogenerated carriers. • 20NSCS exhibits highly efficient photocatalytic hydrogen evolution activity and cycling stability. • A possible mechanism for NiS/CdS composite enhanced photocatalytic activity was proposed. [ABSTRACT FROM AUTHOR]

MoS2 stands out as a distinctive material, owing to its two-dimensional structure, with promising potential across various domains notably in energy storage and photocatalysis. In the present work, a pH-assisted hydrothermal approach (one step) has been utilized to synthesize MoS2 nanoflowers (NFs) using ammonium molybdate and thiourea. Characterization of the prepared MoS2 NFs was conducted using XRD, FESEM, HRTEM, FTIR, Raman, UV–Vis, PL, BET and XPS techniques. XRD analysis reveals the hexagonal structure of the prepared NFs, while SEM & TEM images confirm the flower-like morphology consisting of many thin petals. Band gap energy determined through the absorption spectrum is 1.9 eV. Notably, the PL spectrum exhibits a strong and broad peak at 688 nm attributed to band-to-band transition indicating multilayer formation of MoS2 NFs, which is further confirmed by Raman spectroscopy. XPS also confirms the formation of MoS2 showing Mo+4 and S−2 valance states. The specific surface area of MoS2 NFs is found to be 108.446 m2 g−1 that is very high compared to similar materials. Electrochemical properties of MoS2 NFs were also investigated showing a specific capacitance of 761 F g−1 at 4 A g−1 with an energy density of 21 Wh kg−1 and a power density of 886 Wkg−1 for the MoS2 NFs-based electrode. Moreover, photocatalytic degradation of MB using MoS2 NFs at different weight contents (10, 15, 20 and 25 mg) was explored demonstrating highest 97% degradation of MB within 90 min with 20 mg photocatalyst loading along with 0.04 min−1 reaction rate. It also shows good reusability for four consecutive cycles. Furthermore, photodegradation mechanism has also been explored. [ABSTRACT FROM AUTHOR]

The novel flower shaped nanomaterials, known as Nanoflowers (NFs), have attracted the interest of the scientific community around the world with their unique morphology, ease of synthesis, large surface-to-volume ratio, and high electron conductivity, making them a promising nanomaterial for various relevant applications. Bimetallic NFs comprise of two different metallic elements, with superior properties due to the synergistic effect between the hereditary properties of the constituent metal atoms. Bimetallic NFs can be synthesized through various methods, each offering unique advantages. Conventional methods provide a traditional approach to NF synthesis, while electrodeposition methods offer precise control over NF morphology and composition. Biological methods harness the power of biological systems for green and sustainable NF synthesis. Various characterization techniques for identifying the morphology of NFs include HR-TEM, SEM, EDX, XRD etc. These NFs exhibit exemplary catalytic activity with high selectivity and catalytic yield due to their large surface areas and augmented active site density. This review delineates the synthesis, morphology, electronic properties and catalytic applications of bimetallic NFs. The manuscript depicts various catalytic reactions and focuses on mechanism and role of bimetallic NFs in these reactions. Moreover, the recent challenges and future prospects of these bimetallic NFs are well discussed in detail. [ABSTRACT FROM AUTHOR]

The use of organic-inorganic hybrid nanoflowers as a support material for enzyme immobilization has gained significant attention in recent years due to their high stability, ease of preparation, and enhanced catalytic activity. However, a major challenge in utilizing these hybrid nanoflowers for enzyme immobilization is the difficulty in handling and separating them due to their low density and high dispersion. To address this issue, magnetic nanoflowers have emerged as a promising alternative enzyme immobilization platform due to their easy separation, structural stability, and ability to enhance catalytic efficiency. This review focuses on different methods for designing magnetic nanoflowers, as well as future research directions. Additionally, it provides examples of enzymes immobilized in the form of magnetic nanoflowers and their applications in environmental remediation, biosensors, and food industries. Finally, the review discusses possible ways to improve the material for enhanced catalytic activity, structural stability, and scalability. The magnetic hybrid nanoflowers embedded with enzymes exhibit superior catalytic activity, excellent stability, and ease of separation which can be used in a wide range of applications. Magnetic nanoflowers can be used as a novel platform for enzyme immobilization. There are three different approaches to the synthesis of efficient magnetic nanoflower. The magnetic nanoflowers provides excellent stability and good reusability of enzymes. The hybrid biocatalyst was applied in biotransformation, environmental, and food applications. The challenges and their remedies of hybrid biocatalyst have been discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] Facile synthesis of high-efficiency and stable bifunctional electrocatalyst is essential for producing clean hydrogen in energy storage systems. Herein, low Rh-doped flower-like Ni 3 S 2 /Co 3 S 4 heterostructures were facilely prepared on porous nickel foam (labeled Rh-Ni 3 S 2 /Co 3 S 4 /NF) by a hydrothermal method. The correlation of the precursors types with the morphological structures and catalytic properties were rigorously investigated for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in the control groups. The low Rh doping within the catalyst played important role in boosting the catalytic characteristics. The resulting catalyst showed the smaller overpotentials of 197 and 78 mV to drive a current density of 10 mA cm−2 for the OER and HER in alkaline electrolyte, respectively. And the potential only required 1.71 V to drive a current density of 100 mA cm-2 in a water splitting device. It reflects excellent overall water splitting of the home-made Rh-Ni 3 S 2 /Co 3 S 4 /NF. This strategy shed some constructive light for preparing transition metal sulfide-based electrocatalysts in water splitting devices. [ABSTRACT FROM AUTHOR]

Removal of heavy metals becomes increasingly crucial for public health and the environment. In this regard, Bi2S3 nanoflowers were produced for heavy metal ion removal applications. Nanoflowers are fabricated using hydrothermal synthesis, and then tested as adsorbents for the removal of lead (Pb2+) ions from aqueous systems. To assess the morphological and chemical characteristics, Bi2S3 nanoflowers were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) techniques. Flame atomic adsorption spectroscopy (FAAS) was used in the assessment of heavy metal ion recovery. To determine the optimum conditions of the adsorption system, the effect of different parameters such as pH, eluent type and amount, adsorbent dose, adsorbent time, etc. were investigated. For lead removal, the optimum pH value was determined as 5.0, eluent dose and type were found 1 M HNO3. For 20 mL, the optimum adsorbent dose and time were found 50.0 mg, and 30 min, respectively. The adsorption capacity of the Bi2S3 nanoflowers was found to be quite higher than the results reported in similar works. It was illustrated that Bi2S3 nanoflowers have great potential to be used in water remediation applications as sorbent material. [ABSTRACT FROM AUTHOR]

Hybrid supercapacitors (HSCs) bridge the unique advantages of batteries and capacitors and are considered promising energy storage devices for hybrid vehicles and other electronic gadgets. Lithium‐ion capacitors (LICs) have attained particular interest due to their higher energy and power density than traditional supercapacitor devices. The limited voltage window and the deterioration of anode materials upsurged the demand for efficient and stable electrode materials. Two‐dimensional (2D) molybdenum sulfide (MoS2) is a promising candidate for developing efficient and durable LICs due to its wide lithiation potential and unique layer structure, enhancing charge storage efficiency. Modifying the extrinsic features, such as the dimensions and shape at the nanoscale, serves as a potential path to overcome the sluggish kinetics observed in the LICs. Herein, the MoS2 nanoflowers have been synthesized through a hydrothermal route. The developed LIC exhibited a specific capacitance of 202.4 F g−1 at 0.25 A g−1 and capacitance retention of >90 % over 5,000 cycles. Using an ether electrolyte improved the voltage window (2.0 V) and enhanced the stability performance. The ex‐situ material characterization after the stability test reveals that the storage mechanism in MoS2‐LICs is not diffusion‐controlled. Instead, the fast surface redox reactions, especially intercalation/deintercalation of ions, are more prominent for charge storage. [ABSTRACT FROM AUTHOR]

The current study, accurately designed and created a two-dimensional (2D) structure of SnO 2 nano-flowers and In 2 O 3 nanoparticles using a simple hydrothermal technique and sol-gel method, respectively. On the outer surface of SnO 2 nanoflowers the In 2 O 3 nanoparticles were uniformly growing, clearly revealed by field emission scanning electron microscopic. Besides, crystal phase structure, surface area and elementals composition were characterized by XRD, BET, TEM, EDS, XPS and the gas sensing properties of In 2 O 3 @SnO 2 NFs. The results exhibited that 2 wt% In 2 O 3 @SnO 2 NFs sensor is highly sensitive to NO 2 , the response (R g /R a) to 30 ppm NO 2 is 94.5, and at 50 ppb the response measured 0.61 at 150 °C, the response time is 32 and 51s, respectively, along with good moisture resistance. Besides along with excellent selectivity, long-term stability, and relative humidity (RH) in high-humidity environment, the 2 wt% In 2 O 3 @SnO 2 NFs still maintain high response 91 at 30 ppm. More importantly, at room temperature the response was (Rg/Ra = 1.01) at detection limit 300 ppb towards NO 2 , which could use be for trace NO 2 gas detection. The large specific surface areas of SnO 2 , the abundance of oxygen species adsorbed on the surface, the distinctive electron transformation between heterojunction materials, and high electron transmission channel of SnO 2 and In 2 O 3 transition layer were all considered to have a synergistic effect thatin2 contributed to excellent sensing properties of In 2 O 3 @SnO 2 NFs. [ABSTRACT FROM AUTHOR]

[Display omitted] Although cobalt nitride (CoN)-based nanomaterials have been widely designed as advanced oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and oxygen reduction reaction (ORR) catalysts, the continuous consumption of lithium-ion batteries (LIBs) has led to a high price of cobalt metal. Therefore, in the future, recycling valuable Co elements from spent devices and boosting their service efficiency will inevitably promote the utilization of Co-based materials in water splitting and zinc-air batteries (ZABs). Herein, we realize the Co recycling from spent LIBs by a simple hydrometallurgy method. Under the assistance of hexamethylenetetramine and polystyrene spheres, after the hydrothermal and pyrolysis treatment in the NH 3 atmosphere, the as-reclaimed cobalt oxalates were successfully transformed into novel three-dimensional (3D) CoN nanoflowers (denoted as CoN NFs). Benefiting from the unique 3D flower-like architectures, intrinsic high conductivity, large surface area, uniformly dispersed CoN nanoparticles, and the synergistic effect between Co 3 N and CoO phases, the 3D flower-like CoN NFs exhibited excellent OER catalytic activity. The performance was much better than commercial RuO 2 in the 1.0 M KOH solution. Furthermore, the CoN NFs-based water splitting cell needed a voltage of 1.608 V to achieve the current density of 10 mA cm−2, which is even 16 mV smaller than that of Pt/C||RuO 2 benchmark (1.624 V). Meanwhile, the CoN NFs-derived ZAB exhibited a high peak power density of 107.3 mW cm−2 (vs. 103.2 mW cm−2 of Pt/C-RuO 2 -based ZAB) and a low charge–discharge voltage gap (0.93 V vs. 1.43 V of Pt/C-RuO 2 -based ZAB). Due to the excellent structural and elemental stabilities, the corresponding water splitting cell and ZAB had outstanding durability. This work successfully explored an advanced industrial chain from recycling Co metal in spent devices to designing the high-efficiency HER/OER/ORR electrocatalysts for advanced water splitting devices and ZABs. This will further promote the value-added utilization of valuable Co metal in various energy storage or conversion devices. [ABSTRACT FROM AUTHOR]

β‐Glucosidase, a pivotal enzyme in the synthesis of various glycosides with wide applications in industries such as food, cosmetics, beverages, bioenergy, nutraceuticals, pharmaceuticals, and detergents, undergoes immobilization to enhance its utility in industrial processes and improve enzymatic properties. In this study, the conventional hybrid nanoflower synthesis method was used for β‐glucosidase‐inorganic hybrid nanoflowers. Following a comprehensive pH and temperature scanning of the nanoflowers, the influence of metallic ions and various organic solvents on hybrid nanoflowers to enhance the activity and stability of the biocatalyst were investigated. The optimal morphology for β‐Glu/NFs was determined to be 0.01 mg/mL. To obtain the optimum activity conditions, we explored pH values ranging from 3 to 8 and temperatures between 30 and 80 °C. Both the free form and β‐Glu/NFs exhibited higher activity in acidic conditions, with a significant decrease in activity observed at pH 7 and 8. β‐Glu/NFs demonstrated superior activity compared to the free enzyme in the presence of metal ions, exhibiting a remarkable 3.6‐fold increase in activity in chloroform, and approximately 2.8 and 2.7 times increase in benzene and glycerol, respectively. Moreover, it displayed over a 2‐fold increase in activity in methanol, ethanol, isopropanol, n‐butanol, acetone, and DMSO. [ABSTRACT FROM AUTHOR]

AbstractZinc Oxide (ZnO) nanostructures have proved useful across a wide range of applications like medical technology, electronics, sulfur removal as well as microbial growth control. In the petroleum industry, ZnO nanostructures have been widely researched for application in Drilling Fluids. ZnO has been previously reported to work excellently in enhancing the electrical and thermal properties of water-based drilling fluids (WBDFs). However, the role of morphological features of the nanostructures in influencing the properties of bentonite-laden WBDFs is less understood. In this work, ZnO nanostructures were synthesized under microwave irradiation which resulted in different shapes like rods and flowers. The effect of microwave power and time was observed with Field Emission Scanning Electron Microscopy (FE-SEM) and Dynamic Light Scattering (DLS), and a suitable synthesis criterion was selected for achieving the smallest complex ZnO nanoflowers. These nanoflowers were further characterized for functional group and structural identification. Bentonite/Polymer Nanofluids were prepared and tested for properties like rheology, API, and HPHT filtration before and after thermal aging at 150 °C. The results show ZnO nanoflowers in WBDFs have excellent filtration control ability with ∼56% reduction in HPHT filtrate volume and can impart a flat-line rheological profile. Also, the breaking of nanoflowers into smaller nanorods and some further textural changes is predicted to enhance the stability of the WBDFs due to better dispersion and compact mud cake formation. The study shows that the morphological features of metal oxide nanostructures can be controlled with microwave irradiation and play an effective role in controlling the properties of bentonite/polymer WBDFs. [ABSTRACT FROM AUTHOR]

This study targeted developing a novel Zinc oxide with alpha hematite nanoflowers (NFs)-loaded bee venom (Bv) (Bv-ZnO@αFe2O3 NFs) as a bio-natural product from bees to combine both the advantages of combination magnetic properties and the antimicrobial and anti-biofilm properties on isolated coliform bacteria from the effluent of wastewater treatment plants. About 24 isolates of treated wastewater isolates were multidrug resistant (MDR). The phylogenetic grouping of Escherichia coli (E. coli) and Klebsiella pneumonia (K. pneumonia) showed that the largest group was Group A, followed by Group B2 and Group B1. Fourier transform infrared (FTIR), The X-ray diffraction (XRD), and scanning electron microscopy-energy dispersive X-ray analysis (SEM− EDX) validated the coating operation's contact with Bv onto ZnO@αFe2O3 NFs. According to high-resolution transmission electron microscopy (TEM) and selected area electron diffraction (SAED), pattern analyses for prepared nanoformulations exhibited a spherical shape of αFe2O3 (~9–15 nm), and floral needle shapes with uniform distribution of size with aggregation of ZnOαFe2O3 and Bv-ZnO@αFe2O3 NFs around (~100–200 nm). The toxicity of Bv-ZnO@αFe2O3 NFs was comparable up to 125 µg mL−1, when it reached 64.79% (IC50, 107.18 µg mL−1). The antibacterial activity showed different zones of inhibition against different isolates. The biofilm inhibitory activity of NPs and NFs showed a highly significant reduction (p < 0.001) in treated biofilms with ZnO@αFe2O3 and Bv-ZnO@αFe2O3. In essence, ZnO@αFe2O3 and Bv-ZnO@αFe2O3 NFs are promising antimicrobials for inhibiting the growth and biofilm of MDR E. coli and K. pneumonia isolates, thereby, biocontrol of wastewater. [ABSTRACT FROM AUTHOR]

In this work, flower-like zinc oxide (ZnO) nanostructures were synthesized using hydrothermal synthesis. The fabricated nanoflowers were used as adsorbents for the removal of heavy metal ions such as lead and chrome. Morphological assessments and chemical investigations of the ZnO nanoflowers were conducted by using X-ray diffraction, field emission electron microscopy, energy dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy techniques. To optimize the heavy metal recovery process optimum parameters like pH, eluent type, adsorbent amount, solution volume, and adsorption time were studied; flame atomic absorption spectrometry was used in the optimization process. The optimum conditions for Cr(VI) and Pb(II) were determined as 3 M HNO3, pH 6.5, 20 mL, 30 min. But the amount of ZnO nanoflowers for Cr(VI) and Pb(II) was determined as 200 and 50 mg, respectively. Outstanding heavy metal ion removal performance of the ZnO nanoflowers was achieved on spinach (NIST-SRM1570a), and apple leaf (NIST-SRM 1515) for the method validation where the solid phase extraction technique was used as the main enrichment method. The flame AAS method was applied to determine for Cr(VI) and Pb(II) metal ions in real samples (spinach, rocket leaf, collard leaf, parsley, bottled drinking water and hardaliye), after and before enrichment on the present ZnO. Relative standard deviation (%RSD) was found in the range of 0.2–5.3. [ABSTRACT FROM AUTHOR]

The present study depicts, synthesis and physicochemical investigations of zinc oxide nanoflowers (ZnO NFs). X-ray diffraction (XRD) profile of ZnO NFs revealed that ZnO NFs exhibit hexagonal wurtzite-type structure of crystallinity with P63mc space group. Microstructural analysis displays a uniform flower-like shape of ZnO NFs with petals ranging from 1 to 2 μm and an overall size of 12 µm. The absorption spectrum of ZnO NFs showed characteristic peak at 365.7 nm with an optical energy band gap of 3.40 eV. The photocatalytic activity of the ZnO NFs was evaluated by exposing crystal violet (CV) dye to UV light in the presence of the ZnO NFs. The UV–Vis spectra showed a significant decrease in the intensity of the absorbance peak at ~ 590 nm, corresponding to the degradation of the dye. The degradation followed a first-order rate equation with a rate constant of 0.0404 min−1 and excellent fit to the experimental data (R2 = 0.987). Furthermore, the ZnO NFs displayed excellent reusability, with more than 90% removal efficiency after 5 cycles. These findings demonstrate the potential of ZnO NFs as an effective photocatalyst for removing toxicity from aqueous solutions. Hall effect measurements revealed the n-type character of ZnO NFs and their resistivity, carrier concentration and Hall mobility were found to be 29 Ω cm, 7.53 × 106 cm−3, and 2.48 cm2/V s, respectively. [ABSTRACT FROM AUTHOR]

Designing anisotropic lignin-based particles and promoting the high-value utilization of lignin have nowadays drawn much attention from scientists. However, systematic studies addressing the self-assembly mechanisms of anisotropic lignin-based particles are scarce. In this work, an interaction including the electrostatic forces and chelating forces between lignin and Ag+ was regulated via carboxymethylation modification. Subsequently, the aggregation morphology of carboxymethylated lignin in a Ag+ solution was observed via SEM. The result showed that a large number of Ag+ intercalated into the lignin molecules when the grafting degree of the carboxyl groups increased from 0.17 mmol/g to 0.53 mmol/g, which caused the lignin molecules to gradually transform from disordered blocks to ordered layers. Dynamics research indicated that the adsorption process of Ag+ in carboxymethylated lignin conforms to the Pseudo-first-order kinetic model. The saturated adsorption amount of Ag+ in the carboxymethylated lignin reached 1981.7 mg/g when the grafting rate of carboxyl groups increased to 0.53 mmol/g, which then fully intercalated into lignin molecules and formed a layered structure. The thermodynamic parameters showed that the thermal adsorption process conforms to the Langmuir model, which indicates that Ag+ is monolayer-adsorbed and intercalated into lignin molecules. Meanwhile, the ΔH values are more than 0, which suggests that this adsorption process is a endothermic reaction and that a higher temperature is conducive to an adsorption reaction. Therefore, self-assembly of lignin in a Ag+ solution under 70 °C is more conducive to the formation of a nanoflower structure, which is consistent with our experimental result. Finally, pH-responsive Pickering emulsions were successfully prepared using a lignin-based nanoflowers, which demonstrated their potential as a catalytic platform in the interface catalysis field. This work offers a deeper understanding into the formation mechanism of anisotropic lignin-based nanoflowers and hopes to be helpful for designing and preparing anisotropic lignin-based particles. [ABSTRACT FROM AUTHOR]

Hydrothermal synthesis technique was employed to synthesize molybdenum diselenide (MoSe2) nanoflowers from three different molybdenum precursors including sodium molybdate, ammonium molybdate and molybdenum trioxide. The hydrothermal reaction of one of the precursor of molybdenum and selenium powder took place in an autoclave at 210 °C for 48 h. The reaction temperature, molar ratio of precursors and reaction time were fixed in all three reactions. The as obtained powder was characterized using various characterization techniques before further processing. Successful synthesis of MoSe2 nanoflowers was confirmed through FESEM analysis after which the powder was further processed to synthesize MoSe2 quantum dots (QDs). Additionally, thin films of all the materials were synthesized under the same conditions, and a two-terminal device setup was used to analyze their transport characteristics. Electrical conductivity, carrier concentration, and mobility of all the samples were determined using Hall measurements and current–voltage characteristics in the 30–70 °C temperature range. The sample made with sodium molybdate was found to have the least amount of leakage current, making it suitable for use in high power and high voltage applications. Although the other two samples had moderate to high leakage currents, they were more conductive than the sodium molybdate sample, allowing them to be used in situations where leakage current could be limited or controlled by outside sources. The outcomes show that the electrical characteristics of MoSe2 are significantly influenced by the molybdenum precursors used. [ABSTRACT FROM AUTHOR]

The occurrence of contaminants in the environment requires very sensitive analytical techniques for their determination. For that, analytical techniques have been recently improved by nanotechnologies. Here, we review nanoflowers, which are nanomaterials with flower-like morphologies, with focus on their synthesis, characterization and analytical applications. Synthesis methods include coprecipitation, sol–gel, solvothermal, hydrothermal, chemical vapor deposition, microwave-assisted, electrochemistry, sonochemistry and biosynthesis. Characterization can be done by microscopy, e.g., scanning electron, transmission electron and atomic force; by spectroscopy, e.g., ultraviolet–visible, Raman, Fourier transform infrared, atomic absorption spectrophotometry, dynamic light scattering and mass spectrometry; by chromatography, e.g., liquid, hydrodynamic and gel permeation; by X-ray fluorescence, diffraction and photoelectron spectroscopy; and by thermal gravimetry, differential centrifugal sedimentation and nanoparticle tracking analysis. Analytical applications include nanoflowers coupled to chromatography or sensors to detect organic and inorganic compounds. Nanoflowers are easy to prepare, and they display high surface area, high efficiency, high stability and cost-effectiveness. [ABSTRACT FROM AUTHOR]

Polyoxometalates (POMs) with small-sized, high specific surface area, high negative charges, tunable chemical composition and unique geometrical structure, as well as self-assembly behavior have been widely employed as the transferable building block to construct target catalyst. However, there is lack of effective strategy to display their intrinsic activity for electrochemical hydrogen evolution reaction in alkaline condition. Herein, presented is Ni modified PW12 clusters in situ integrated on Ni foam with unique hierarchical structure (Ni-WO/NF), prepared from the Ni modified Keggin-type phosphotungstic acid (H3PW12O40) through the facile hydrothermal method by optimizing the volume ratio of ethanol and deionized water. The as-synthesized Ni-WO/NF possessed abundant active sites, unique micro-nanostructure, and fast charge-transfer ability at interface. Benefiting from these advantages, the optimized Ni-WO/NF exhibited superior hydrogen evolution reaction. (HER) performance with lower overpotential of 75 mV at 10 cm−2 in 1 M KOH, accompanying with a Tafel slope of 86 mV dec−1. Our discovery offers an approach to prepare heteroatom modified materials with hierarchical structure at the cost-effective HER catalysts. [ABSTRACT FROM AUTHOR]

In this work, we report a low-cost and highly sensitive electrochemical sensor for detecting As(III) in water. The sensor uses a 3D microporous graphene electrode with nanoflowers, which enriches the reactive surface area and thus enhances its sensitivity. The detection range achieved was 1–50 ppb, meeting the US-EPA cutoff criteria of 10 ppb. The sensor works by trapping As(III) ions using the interlayer dipole between Ni and graphene, reducing As(III), and transferring electrons to the nanoflowers. The nanoflowers then exchange charges with the graphene layer, producing a measurable current. Interference by other ions, such as Pb(II) and Cd(II), was found to be negligible. The proposed method has potential for use as a portable field sensor for monitoring water quality to control hazardous As(III) in human life. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) have been widely studied due to their interesting physicochemical properties and remarkable antibacterial properties. Chemical synthesis methods, including green chemistry, have achieved 0D nanostructures. However, ecological methods have little studied self-assembling Ag nanostructures, such as flowers or dendrites. In this work, Ag dendrites and Ag flower-like morphologies have been successfully synthesized using a one-step green method employing Arctostaphylos pungens Kunth fruit extract at room temperature. The antibacterial properties of both nanostructures were evaluated against Gram-positive Escherichia coli and Gram-negative Staphylococcus aureus bacteria. Scanning electron microscopy (SEM), X-ray diffraction (XRD), ultraviolet–visible spectroscopy (UV–Vis), and infrared spectroscopy (IR) characterized the synthesized products. The morphological changes of the nanostructures come from the variation in the concentration of the precursor salt, silver nitrate (AgNO3). A growth mechanism is proposed that includes the formation of nanospheres and their subsequent transformation into Ag dendrites. Both nanostructures show good antibacterial activity against the tested microorganisms. The Ag dendritic nanostructures presented inhibition zones of 11 mm and 10.7 mm against Escherichia coli and Staphylococcus aureus bacteria. However, the flower-like structure was slightly less effective, presenting 11 and 9.5 mm inhibition zones against the same microorganisms, respectively. [ABSTRACT FROM AUTHOR]

Zinc Oxide (ZnO) has a huge potential in absorbing light quanta and solar spectrum. Being an appealing semiconductor, ZnO has been synthesized widely to escalate its ability as a nanostructure. In this review, nanostructures of ZnO have been studied as a means to provide simple approaches using anodization. 1 D nanostructures of nanorods, nanotubes and nanowires, and 3 D nanostructures of nanoflowers are chosen due to these dimensional structures synthesized thrivingly via anodization. Observations were made on parameters of times, voltages, and electrolyte concentration. The enlightenment of these synthesis presents the simple approaches and understanding to be imposed on for future endeavor. [ABSTRACT FROM AUTHOR]

Introducing oxophilic metals into Pt‐based alloy catalysts can effectively alleviate the poisoning by CO intermediates (CO*) during methanol oxidation reactions (MOR). However, excessive oxophilic metals on the surface of catalysts tend to form thermodynamically stable carbonyl compound‐like structures, occupying electrocatalytically active sites, which is not conducive to the enhancement of catalytic activity. Herein, a kind of surface segregated FePtRh nanoflowers for effectively eliminating the CO* poisoning during MOR electrocatalysis is presented. The FePtRh nanoflowers are constituted by the Rh‐rich core and Fe‐rich shell. The optimized Fe21Pt66Rh13/C shows a high mass activity of 3.90 A mgPt−1 and a specific activity of 4.85 mA cm−2. It is confirmed that the electron transfer from Pt to Rh or Fe atoms is beneficial for the higher anti‐CO poisoning ability, which mainly originate from the alloying of Rh atoms and surface‐segregated structures. Density functional theory calculations reveal the decreased electrons adsorbed by CO* on both Pt–Pt bridge sites and top sites weakens the strong adsorption energy between Pt atoms and CO* intermediates. The optimal nanoflowers also show excellent performance toward ethanol oxidation reaction (EOR) with a high mass activity of 2.76 A mgPt−1 and the enhanced anti‐CO poisoning ability, as well as the improved stability. [ABSTRACT FROM AUTHOR]

[Display omitted] • The recent advances in the immobilization of enzymes based on hierarchical NFs was reviewed. • The application of enzymes-inorganic hNFs was summarized. • The information on metrics regarding catalytic performance of the enzymes-inorganic hNFs was comprehensive discussed. In general, enzyme immobilization technologies were applied for seeking to create reusable enzymes with improved enzyme properties for industrial applications. However, to traditional immobilization technologies, such as adsorption, covalent binding, cross-linking, and entrapment, the reusability and stability are improved, the activity is often obviously reduced compared with the free enzyme. To resolve this challenge, the recently appeared hierarchical Nanoflowers (NFs) technology opened a new door for enzyme immobilization, which possesses the inherent merits such as enhanced loading capacity and high specific surface area. Recent researches have clearly stated that it is an inexpensive and environmentally benign technology for enzyme immobilization. In this review, we focus on the recent advances in the immobilization of enzymes with the environmentally benign hierarchical NFs, as well as their application. [ABSTRACT FROM AUTHOR]

The Co2+-doped NiAl-LDH (NiAl-LDH-Co2+- x , x = 0, 0.3, 0.6, 0.9, 1.2, 1.5) nanoflower electrodes with extended layer spacing and electronic modulation are prepared by one-step hydrothermal method for high performance supercapacitors. [Display omitted] Layered double hydroxides (LDHs) with high theoretical capacity have broad prospects in energy storage applications. However, their slow charge transfer kinetics and easy agglomerate hinder their applications in high-performance supercapacitors. Herein, Co2+-doped nickel aluminum layered double hydroxides (NiAl-LDH-Co2+- x , x = 0, 0.3, 0.6, 0.9, 1.2, 1.5) have been designed and prepared by a convenient hydrothermal process. The multicomponent layer structure formed by cobalt doping facilitates sufficient penetration of the electrolyte and accelerates the charge transfer kinetics. Furthermore, the more open layer spacing and electronic interactions induced by Co2+ doping are conducive to accelerating ion de-intercalation, thereby further improving the kinetic behavior of charge storage. Benefiting from the unique microstructure and Co2+ doping effect, the prepared NiAl-LDH-Co2+-0.9 provides a superior specific capacity of 985 C g-1 at 1 A g-1. In addition, the assembled hybrid supercapacitor with the NiAl-LDH-Co2+-0.9 as the positive electrode provides a remarkable energy density of 22.51 Wh kg−1 at a power density of 800 W kg−1 and exhibits an excellent cycle life with 80 % capacity retention after 20,000 cycles. This study demonstrates the great potential of efficient microstructure design and doping strategy in enhancing the charge storage of electrode materials. [ABSTRACT FROM AUTHOR]

The Co2+-doped NiAl-LDH (NiAl-LDH-Co2+- x , x = 0, 0.3, 0.6, 0.9, 1.2, 1.5) nanoflower electrodes with extended layer spacing and electronic modulation are prepared by one-step hydrothermal method for high performance supercapacitors. [Display omitted] Layered double hydroxides (LDHs) with high theoretical capacity have broad prospects in energy storage applications. However, their slow charge transfer kinetics and easy agglomerate hinder their applications in high-performance supercapacitors. Herein, Co2+-doped nickel aluminum layered double hydroxides (NiAl-LDH-Co2+- x , x = 0, 0.3, 0.6, 0.9, 1.2, 1.5) have been designed and prepared by a convenient hydrothermal process. The multicomponent layer structure formed by cobalt doping facilitates sufficient penetration of the electrolyte and accelerates the charge transfer kinetics. Furthermore, the more open layer spacing and electronic interactions induced by Co2+ doping are conducive to accelerating ion de-intercalation, thereby further improving the kinetic behavior of charge storage. Benefiting from the unique microstructure and Co2+ doping effect, the prepared NiAl-LDH-Co2+-0.9 provides a superior specific capacity of 985 C g-1 at 1 A g-1. In addition, the assembled hybrid supercapacitor with the NiAl-LDH-Co2+-0.9 as the positive electrode provides a remarkable energy density of 22.51 Wh kg−1 at a power density of 800 W kg−1 and exhibits an excellent cycle life with 80 % capacity retention after 20,000 cycles. This study demonstrates the great potential of efficient microstructure design and doping strategy in enhancing the charge storage of electrode materials. [ABSTRACT FROM AUTHOR]

This article discusses the features of the synthesis and application of porous two-dimensional nanomaterials in developing conductometric gas sensors based on metal oxides. It is concluded that using porous 2D nanomaterials and 3D structures based on them is a promising approach to improving the parameters of gas sensors, such as sensitivity and the rate of response. The limitations that may arise when using 2D structures in gas sensors intended for the sensor market are considered. [ABSTRACT FROM AUTHOR]

The present study reported the synthesis of SnS2 nanoparticles by using a thermal decomposition approach using tin chloride and thioacetamide in diphenyl ether at 200 °C over 60 min. SnS2 nanoparticles with novel morphologies were prepared by the use of different alkylamines (namely, octylamine (OCA), dodecylamine (DDA), and oleylamine (OLA)), and their role during the synthesis was explored in detail. The synthesized SnS2 nanostructures were characterized using an array of analytical techniques. The XRD results confirmed the formation of hexagonal SnS2, and the crystallite size varied from 6.1 nm to 19.0 nm and from 2.5 to 8.8 nm for (100) and (011) reflections, respectively. The functional group and thermal analysis confirmed the presence of organics on the surface of nanoparticles. The FE-SEM results revealed nanoparticles, nanoplates, and flakes assembled into flower-like morphologies when dodecylamine, octylamine, and oleylamine were used as capping agents, respectively. The analysis of optical properties showed the variation in the bandgap and the concentration of surface defects on the SnS2 nanoparticles. The role of alkylamine as a capping agent was explored and discussed in detail in this paper and the mechanism for the evolution of different morphologies of SnS2 nanoparticles was also proposed. [ABSTRACT FROM AUTHOR]

The work presents an innovative methodology for the fabrication of zinc oxide (ZnO) nano-flowers by utilizing a chemical method and an organic agent Dimethylformamide (DMF). The XRD results confirm high crystallinity and the presence of all the ZnO diffraction peaks, and 98% agreement with the Inorganic Crystal Structure Database (ICSD) of XRD data. The results of the scanning electron microscope (FESEM) indicate the presence of nanostructures of flowers with nano-branches that are organized in size and shape. Energy dispersive X-ray (EDS) results in a match with the XRD results and did not show the presence of any impurities in the sample crystallization. Optical measurements confirm the ZnO has an optical energy gap of 3.37 eV with notable absorbance in the visible and ultraviolet regions. The results of antibacterial activity against Escherichia coli, Staphylococcus, Pseudomonas, and Streptococcus bacteria confirm that the ZnO nanoflowers have high inhibition zones in all bacteria due to its the unique surface characteristics. [ABSTRACT FROM AUTHOR]

Bioinspired molecular and macromolecular systems could be a driver for new generation semiconductor‐synthetic biology (Semi‐Syn‐Bio) technologies, shifting the materials design paradigm by utilizing bioinspired and biological structures to design molecular and supramolecular architectures as bionanomaterials in the fabrication of devices and components. Herein, a simple and rapid self‐assembly approach of interfacial coordination programming of a biological amphiphile, a fatty acid, using a transition metal ion, copper cation (Cu2+) to direct the formation of nanoflowers of Cu2+‐conjugated supramolecular structures is demonstrated. The fatty acid molecules form complexes with the copper ions and then self‐assemble into microstructures with flower‐like petals, which are highly nanoporous thin sheets. The growth of microstructures is found to be independent from the precursors' stoichiometric ratios, demonstrating a versatile interfacial coordination programming approach to make crystalline, uniquely shaped‐double peony flower‐like microstructures. It is anticipated that design principles and directed self‐assembly approaches for the interfacial coordination programming of biomolecules may advance the state‐of‐the‐art of biomaterials research, providing deeper understanding in the paradigm of design, synthesis, self‐assembly, and fabrication of Semi‐Syn‐Bio superstructure systems. [ABSTRACT FROM AUTHOR]

β-lactoglobulin (β-LG) is a significant allergen in milk. Enzymatic hydrolysis of β-LG produces peptides with low allergenicity and improved functionality. The biocatalytic membranes combine enzyme function and membrane separation in one step, but is still challenging for proteolysis. Herein, the biocatalytic membranes embedded with trypsin-inorganic hybrid nanoflowers are developed by a facile and green method for β-LG hydrolysis. Ethylene vinyl alcohol copolymer (EVAL) nanofibers are fabricated as 3D scaffolding on the membrane surface and trypsin-copper phosphate nanoflowers are in-situ grown in the porous structure of membranes. The nanoflowers are uniformly entrapped in the EVAL nanofiber layer and preferentially grow in the EVAL nanofibers layer, leading to the hierarchical structure of membranes. The trypsin loading of the nanoflowers membrane is approximate to 282.1 µg/cm2. Lower Michaelis-Menten constants Km prove the better affinity of Cu 3 (PO 4) 2 -TR nanoflower membrane with substrates during filtration than that in static mode, even than free trypsin. The hierarchical structure of the membranes ensures both the enhanced trypsin-substrate contacts and low mass transfer resistance during the β-LG filtration. This work not only presents a novel concept of enzyme immobilized biocatalytic membranes, but also offers a sustainable solution for high-performance proteolysis. [Display omitted] [ABSTRACT FROM AUTHOR]

Birnessite is a phyllomangante mineral widely found in surficial environments. Its morphology not only affects its adsorption and oxidation properties but also indicate changes in the climatic conditions of ancient Earth. This study explored how preparative parameters affect the morphology and reactivity birnessite. Synthesized at boiling temperatures, birnessite nanoflowers measured 265 nm with a specific surface area (SSA) of 34.87 m2/g, while at 65 °C, they increase to 2251 nm with a similar SSA of 30.33 m2/g. Lowering KMnO 4 or HCl concentrations increased nanoflower size. Reduced concentration of KMnO 4 hindered Coulombic forces, fostering a parallel petal arrangement and a higher SSA (59.11 m2/g). Lower concentration of HCl led to perpendicular petals and a reduced SSA (12.33 m2/g). Decreased concentrations of both KMnO 4 and HCl reduced initial δ-MnO 2 concentration, allowing time for edge-to-edge assembly and nanoflake substrate formation. Subsequently, δ-MnO 2 vertically assembled on substrates to form microwalls with SSA of 85.39 m2/g. Organic acids as capping agents disrupted this assembly. Adsorption tests for Cd2+ revealed microwalls achieved 7102 mmol/kg, surpassing original birnessite nanoflowers at 2114 mmol/kg. These results provide insights into the crystallization processes and reactivity of natural birnessite, as well as methods for the controllable synthesis of nanoflowers. [Display omitted] In this study, natural birnessite analogs were synthesized under various conditions, including temperature, oxidizing and reducing agents, ionic strengths, particle concentrations, and capping agents. • Characterization revealed the formation of birnessite nanoflowers with a diameter of 3 μm and no significant change in specific surface area (SSA, 30.3 3 m2/g) when the synthesis temperature was 60 °C. • A lower KMnO 4 concentration resulted in a parallel petal arrangement and an increased SSA of 59.11 m2/g. • Reduced concentrations of both KMnO 4 and HCl led to nano-wall morphology with an SSA of approximately 85.39 m2/g. • The addition of organic acids as capping agents hindered (001) plane assembly. • Adsorption tests for Cd2+ revealed microwalls achieved 7102 mmol/kg, surpassing original birnessite nanoflowers at 2114 mmol/kg. [ABSTRACT FROM AUTHOR]

Ammonia (NH 3) is an odorless gas with a pungent smell that can affect health differently based on exposure and concentration. In this study, indium oxide was decorated with cobalt oxide (In 2 O 3 /Co 3 O 4) flower-like nanocomposites (NFs) as gas-sensitive materials, revealing p-type semiconducting characteristics. The detection of ammonia (NH 3) at low concentrations is a significant challenge for chemoresistive gas sensors. Porous Co 3 O 4 nanoflowers were combined with In 2 O 3 nanoparticles to form p-n heterojunctions for NH 3 detection. The p-n heterojunction effect and the capability of the sub-valent band to hold vacancies within In 2 O 3 nanoparticles effectively inhibit electron-hole recombination and extend the carrier lifetime. The In 2 O 3 /Co 3 O 4 = 0.04 ratio-based gas sensor exhibited excellent selectivity, achieving a low detection limit of 500 ppb for NH 3 at 250 °C. The rapid diffusion of gas within the porous Co 3 O 4 NSs and In 2 O 3 nanoparticles accounted for the high response (7.72) and fast response/recovery time (92 s/51 s) of the In 2 O 3 /Co 3 O 4 -based gas sensor to 10 ppm NH 3. This study presents a method for fabricating NH 3 gas sensors with trace-level detection capabilities by adjusting the band structure of nanoparticles and three-dimensional metal-oxide nanostructures. [ABSTRACT FROM AUTHOR]

• Synthesis of graphene oxide (GO) and ZnO nanoflower (NF). • Using four amounts of GO for enhancement of sensing behavior of ZnO NF gas sensor. • Ag interdigitated electrodes was patterned by lift-off technique of lithography. • Functionalization of reduced-GO could decrease the working temperature of ZnO NFs. • The reported sensor showed good sensitivity, stability, and repeatability. This research presents a sensitive resistive ethanol gas sensor based on reduced graphene oxide (rGO)-functionalized Zinc oxide nanoflowers (ZnO NFs). Upon completion of synthesis, the resulting nanostructures were cast onto the photolithographed silver interdigitated electrodes positioned on an Al 2 O 3 substrate. The graphene oxide (GO) with a low oxidation degree was synthesized using a Hummer's method. In the pursuit of optimizing sensing performance, rGO-functionalized ZnO NFs were synthesized through a one-pot hydrothermal process, utilizing different initial quantities of GO (0 mg, 2 mg, 8 mg, and 12 mg). According to the gas sensing measurements, the fabricated sensor with 8 mg initial GO showed the highest response to ethanol at 250 °C. The results show that the GO addition reduced the optimal working temperature of the pure ZnO NFs from 350 °C to 250 °C. The sensor exhibited a good selectivity, repeatability, and high long-term stability. Enhanced ethanol sensing response of the optimized gas sensor was related to the formation of p-n heterojunction between p-type rGO (formed during hydrothermal process at 200 °C) and n-type ZnO and the presence of the optimal amount of rGO on the surface of NFs. The results obtained in this investigation stress the significance of pinpointing the optimal quantity of GO for producing rGO-ZnO nanoflowers with the highest possible sensitivity to ethanol gas. [ABSTRACT FROM AUTHOR]

Vanadium oxides are commonly utilized as cathode materials in aqueous zinc-ion batteries (AZIBs) due to their high capacity performance. However, the conductivity is weak, and they are prone to dissolution during the charging and discharging process. Therefore, it is essential to improve the electrochemical performance of vanadium oxide in AZIBs through modification. In this study, a surfactant was used to refine the microstructure of hydrated vanadium pentoxide. Subsequently, a carbon reduction reaction at high temperatures was employed to convert it into V 2 O 3. Furthermore, nitrogen doping was introduced by coating V 2 O 3 with carbon to create V 2 O 3 @NC nanoflowers in an oxygen-free environment. Experimental results demonstrated that V 2 O 3 @NC exhibited outstanding performance as a cathode material, achieving an initial capacity of 414.0 mAh g−1 at a current density of 0.1 A g−1 and maintaining a capacity retention of 63% after 500 cycles at 1 A g−1. This research expands the possibilities for improving zinc-ion storage in AZIBs by utilizing vanadium-based materials. [Display omitted] • V-based cathode material with nanoflower structure has been prepared to enhance the performance of AZIBs. • The V 2 O 3 @NC delivers excellent electrochemical performance as AZIBs cathode materials. • During the Zn2+ intercalation/de-intercalation process, the wide space between nanoflowers can limit volume growth. • During the cycling process, the carbon layer can stabilize the morphology and structure of V 2 O 3 @NC. [ABSTRACT FROM AUTHOR]

Research in electrochemical detection in lateral flow assays (LFAs) has gained significant momentum in recent years. The primary impetus for this surge in interest is the pursuit of achieving lower limits of detection, especially given that LFAs are the most widely employed point-of-care biosensors. Conventionally, the strategy for merging electrochemistry and LFAs has centered on the superposition of screen-printed electrodes onto nitrocellulose substrates during LFA fabrication. Nevertheless, this approach poses substantial limitations regarding scalability. In response, we have developed a novel method for the complete integration of reduced graphene oxide (rGO) electrodes into LFA strips. We employed a CO 2 laser to concurrently reduce graphene oxide and pattern nitrocellulose, exposing its backing to create connection sites impervious to sample leakage. Subsequently, rGO and nitrocellulose were juxtaposed and introduced into a roll-to-roll system using a wax printer. The exerted pressure facilitated the transfer of rGO onto the nitrocellulose. We systematically evaluated several electrochemical strategies to harness the synergy between rGO and LFAs. While certain challenges persist, our rGO transfer technology presents compelling potential for setting a new standard in electrochemical LFA fabrication. • Reduced graphene oxide electrodes and lateral flow assay strips fully integrated with a novel methodology. • Streamlined dual-purpose laser solution to reduce graphene oxide, ensure connectivity and impede sample leaking. • Pressure exerted uniformly using a wax printer mechanism to transfer rGO onto nitrocellulose without compromising fluidics. • Exploration of several electrochemical strategies to understand the synergy between rGO and nitrocellulose, a porous matrix. • Proof-of-concept application in an electrochemical LFA for cortisol that still allows optical readouts. [ABSTRACT FROM AUTHOR]

Alpha-fetoprotein (AFP) is frequently used for the detection and diagnosis of various cancers, including liver, endodermal, ovarian, stomach, and other malignant tumors. Additionally, it is utilized to identify conditions such as miscarriage, Down syndrome, and neural tube defects during pregnancy. Therefore, the present study focuses on the development/design of a highly sensitive hybrid conjugate system for the diagnosis of AFP. In this regard, the hybrid conjugate was synthesized using horse radish peroxidase, specific antibodies of AFP and copper (II) ion as inorganic component. The conjugate synthesized with high encapsulation efficiency (97%) was characterized using SEM, EDX, FTIR, and XRD analyses. The hybrid conjugate analyses were conducted in direct and sandwich ELISA test systems, and it was found that the direct method was ineffective. Optimal working conditions were determined in the sandwich ELISA test system. In this method, a linear relationship was plotted between A450, and the AFP concentration in the range of 15.6 to 500 ng/mL(R2 = 0.990), and the cut-off value for this test was calculated as 0.465. The detection range of the conjugate was found to be close to commercial ELISA test kits. The findings indicate that functionalized hybrid conjugate systems have the potential to offer a more economical application in the diagnostic field. Protein-inorganic hybrid material technology shows promise for developing ELISA kits in the diagnostic industry, pending further research on sensitivity, repeatability, and stability. The presented biomolecular engineering approach is promising for the development of optional hybrid systems. [ABSTRACT FROM AUTHOR]

In this study, we reported the synthesis and characterization of Au-doped ZnO hybrid nanostructures via a wet chemical approach and assessed their photocatalytic efficiency for the removal of Rhodamine (Rh–B). X-ray powder diffraction (XRD) has been done to verify the crystal structure, i.e. phase identification, crystallite size, texture, stress, and strain. The XRD patterns demonstrate that the wurtzite structure has been retained and that Au nanoparticles were effectively ingested into the ZnO nanoflowers lattice. This demonstrates that Au nanoparticles are effectively absorbed into the ZnO nanoflowers lattice, considering that peaks shifted in the direction of smaller Bragg's angles. As a result, the size of the crystallites increases from (20.7–25.3) nm, and their microstrain decreases from (0.92–0.72) x 10−3 A0 for pure-ZnO to Au-doped ZnO heterostructures, respectively. Scanning Electron Microscopy (SEM) investigation reveals flower-like structures of pure ZnO while a further closed look indicates that these flowers are made up of a variety of oriented, thorn-like branched NWs with diameters ranging from (50–90) nm and lengths ranging from a few microns. The corresponding EDS evaluation of pure ZnO nanoflowers and Au-doped ZnO heterostructures clearly shows that the noble metal Au NPs are deposited, and enormously safeguard the surface of ZnO nanoflowers. Reducing the Au-doped ZnO band gap which generated a red shift in light absorption, was confirmed by the PL spectra which in turn increased the photocatalytic efficiency and reduced the dye degradation time of Rh–B. The photocatalytic ability of Au-doped ZnO heterostructures considerably increased the photodegradation efficiency of Rh–B molecules from 28 min for pure ZnO to 10 min for Au-doped ZnO heterostructures. Due to their wide surface area and distinct morphology as compared to pure ZnO nanoflowers. • Au-doped ZnO heterostructures have been prepared for the degradation of Rh–B dye. • All films have wurtzite structure. The film doped with Au has large crystallite size. • The EDS shows the presence of all metals in Au–ZnO. • Band gap energy is reduced by Au doping. • Au-doped ZnO heterostructures have high photocatalytic activity for the degradation of Rh–B dye. [ABSTRACT FROM AUTHOR]

Discharging industrial wastewater containing dyes and antibiotics will irreversibly damage the overall environment and human health and prosperity. In this study, magnetic Fe3O4 and MoS2 were loaded on biomass activated carbon (BAC) using co-precipitation and hydrothermal methods, respectively, to obtain MoS2 functionalized magnetic biomass activated carbon (MoS2-mBAC), which was used to remove tetracycline hydrochloride (TC) and crystal violet (CV) in wastewater. A series of characterization methods such as SEM, TEM, FT-IR, XRD, VSM and BET were used. The results showed that MoS2-mBAC has abundant oxygen-containing functional groups, high magnetic properties, large specific surface area (984.05 cm2/g), and MoS2 nanoflowers with a graphene-like structure. Moreover, the whole adsorption process was endothermic, which can be well fitted by pseudo-second-order kinetic and Langmuir model. The maximum adsorption capacity for TC and CV at the optimum pH reached 286.53 mg/g and 568.18 mg/g. Compared to BAC and mBAC, the adsorption performance of MoS2-mBAC was greatly improved. After five cycles, the removal rate was still high. MoS2-mBAC has broad application prospects in wastewater treatment due to its unique advantages, such as wide source, simple process, good performance and high economical availability. First, biomass activated carbon was prepared by chemical activation method, and then molybdenum disulfide functional magnetic biomass activated carbon composite (MoS2-mBAC) was prepared by coprecipitation method and hydrothermal method, respectively. MoS2-mBAC has excellent adsorption and reusability for tetracycline (TC) and crystal violet (CV). [ABSTRACT FROM AUTHOR]

Immobilized enzymes are a significant technological approach to retain enzyme activity and reduce enzyme catalytic cost. In this work, trypsin-incorporated Zn3(PO4)2 hybrid nanoflowers were prepared via mild precipitation and coordination reactions. The controllable preparation of hybrid nanoflowers was achieved by systematically investigating the effects of the raw-material ratio, material concentration and reaction temperature on product morphology and physicochemical properties. The enzyme content of hybrid nanoflowers was about 6.5%, and the maximum specific surface area reached 68.35 m2/g. The hybrid nanoflowers exhibit excellent catalytic activity and environmental tolerance compared to free trypsin, which was attributed to the orderly accumulation of nanosheets and proper anchoring formation. Further, the enzyme activity retention rate was still higher than 80% after 12 repeated uses. Therefore, trypsin/Zn3(PO4)2 hybrid nanoflowers—which combine functionalities of excellent heat resistance, storage stability and reusability—exhibit potential industrial application prospects. [ABSTRACT FROM AUTHOR]

Hierarchical and flower-like nanostructures have attained great attention over the past decades due to their unique and intriguing properties. Considering the advantages of their particular structure and properties, we prepared g-C3N4/MnO2 nanocomposite by microwave heating technique without using any catalysts, templates and organic reagents. The longitudinal and transverse relaxation time of as-synthesized nanocomposites were measured by using 0.55 T MRI instrument. Manganese is the primary origin for MRI and MR signals; therefore, different concentrations of the composite were dissolved in water. Relaxivities were measured by the inverse of relaxation times and plotted against the different concentrations of manganese. MRI results showed that the strength of the imaging signal is directly proportional to the Mn concentration, demonstrating that as-synthesized flower-like nanostructures have excellent T1-weighted MRI performance. This study indicates that the nanocomposite of g-C3N4/MnO2 could be a potential candidate as a bifunctional medical system that combines diagnostic imaging and targeted therapy. [ABSTRACT FROM AUTHOR]

Fabrication of an efficient, economic and earth‐abundant nanocatalyst for H2 production is the centre of attraction in renewable energy technology, but it is still a massive task. In present work, we report a facile modified hydrothermal route to synthesize hierarchical CuO nanoflowers as a noble metal free, proficient photo and electrocatalyst for hydrogen generation. Electrochemical studies were performed over as‐synthesized CuO nanoflowers in both acidic and alkaline medium to record both HER and OER responses. An enhanced HER activity with an overpotential of 1.02 V at −10 mA/cm2 cathodic current density and OER activity with an onset potential at around 1.01 V, respectively, superior to the art of HER and OER bi‐catalyst. Photocatalytic H2 evolution performance exhibits the significant production of 16 mmol/g−1cat in time interval of 8 hours in the presence of Na2S/Na2SO3 sacrificial agent. [ABSTRACT FROM AUTHOR]

High-performance gas sensors have important application prospects in the detection and monitoring of toxic and harmful gases that exist in the environment and workshop. Herein, SnO 2 /ZnO nanoflowers with core-shell like structure were successfully fabricated by a two-step solvothermal method. Morphology and mineral phase characterizations demonstrate that the nanoflowers, composed of a SnO 2 flower core in a diameter of about 50 nm and ZnO nanoparticles embedded in the interstice of SnO 2 petals, has a novel mesoporous hierarchical structure with pore size distributed in about 3 nm and 30 nm and a specific surface area of 36.474 m2/g, benefitting to gas-sensing. The results reveal that, compared to pure SnO 2 nanoflowers, the optimal SnO 2 /ZnO (Zn/Sn is 5%) based gas sensor shows 2.7-fold sensing enhancement, fast response (3 s), long-term stability toward n-butanol. It has an outstanding selectivity to n-butanol rather than other gas, its response toward 100 ppm n-butanol at 200 °C is up to 13, 34, 15 and 32 times of that to acetone, xylene, ammonia and carbon monoxide respectively. Hence, SnO 2 /ZnO nanoflowers can be considered as a practical sensing material for n-butanol detection. [ABSTRACT FROM AUTHOR]

Lipases from Thermomyces lanuginosus (TLL), Rhizomucor miehei (RML), Candida rugosa (CRL), forms A and B of lipase from Candida antarctica (CALA and CALB) and Eversa Transform 2.0 have been immobilized on octyl-agarose beads at two different loads (1 mg/g and saturated support) and treated with phosphate and/or some metallic salts (Zn2+, Co2+, Cu2+). They have been also immobilized on the support modified by the metallic phosphate, usually driving to biocatalyst with lower stability or marginal improvements. The effects of the phosphate/metal modification on enzyme features depended on the loading of the support. Some enzymes (TLL, CRL or CALA), mainly using the highly loaded biocatalysts, showed very significant improvement on enzyme stability after the treatment with some of the metal phosphates (next to a 20-fold factor), improvements that were not justified by the presence of metallic or phosphate ions in solution, as they had negative effects on enzyme stabilities. In some other cases, a significant increase in enzyme activity was detected (e.g., CALB). This could be explained by the modification of the nucleation places of the enzymes by the metallic phosphate, and this could help to explain the good results obtained in the nanoflower immobilization of many enzymes. • Incubation of immobilized lipases in metal phosphates alters their activity/stability. • The effects differ to the immobilization of lipase on metal phosphate-supports. • Free phosphate or metal salts usually have negative effects on enzyme stability. • These results help to explain the positive effects of lipase-nanoflowers. [ABSTRACT FROM AUTHOR]

Four commercial immobilized lipases biocatalysts have been submitted to modifications with different metal (zinc, cobalt or copper) phosphates to check the effects of this modification on enzyme features. The lipase preparations were Lipozyme®TL (TLL-IM) (lipase from Thermomyces lanuginose), Lipozyme®435 (L435) (lipase B from Candida antarctica), Lipozyme®RM (RML-IM), and LipuraSelect (LS-IM) (both from lipase from Rhizomucor miehei). The modifications greatly altered enzyme specificity, increasing the activity versus some substrates (e.g., TLL-IM modified with zinc phosphate in hydrolysis of triacetin) while decreasing the activity versus other substrates (the same preparation in activity versus R- or S- methyl mandelate). Enantiospecificity was also drastically altered after these modifications, e.g., LS-IM increased the activity versus the R isomer while decreasing the activity versus the S isomer when treated with copper phosphate. Regarding the enzyme stability, it was significantly improved using octyl-agarose-lipases. Using all these commercial biocatalysts, no significant positive effects were found; in fact, a decrease in enzyme stability was usually detected. The results point towards the possibility of a battery of biocatalysts, including many different metal phosphates and immobilization protocols, being a good opportunity to tune enzyme features, increasing the possibilities of having biocatalysts that may be suitable for a specific process. [ABSTRACT FROM AUTHOR]

As novel anodic materials for lithium-ion batteries (LIBs), transitional metal selenites can transform into metal oxide/selenide heterostructures in the first cycle, which helps to enhance the Li+ storage performance, especially in terms of high discharge capacity. Herein, well-defined hierarchical CoSeO3‧2H2O nanoflowers assembled using 10 nm-thick nanosheets are successfully synthesized via a facile one-step hydrothermal method. When used as anodic materials for LIBs, the CoSeO3‧2H2O nanoflowers exhibit a considerably high discharge capacity of 1064.1 mAh g−1 at a current density of 0.1 A g−1. In addition, the obtained anode possesses good rate capability and cycling stability. Owing to the superior electrochemical properties, the CoSeO3‧2H2O nanoflowers would serve as promising anodic materials for high-performance LIBs. [ABSTRACT FROM AUTHOR]

Among nanomaterials, we can now distinguish a special class called nanoflowers (NFs). These new nanostructures have aroused the interest of scientists due to the topographic features of nanolayers, the special location which allows a higher surface-to-volume ratio compared to classical spherical nanoparticles, thereby significantly increasing the efficiency of surface reactions for nanoflowers. The main value of nanoflowers is their action as enzyme stabilizers. A protein stability is usually enhanced by immobilization on a nanoflower surface through charge affinity and covalent bonds. The possibility of their use in vivo in biocatalysis, biosensors and medicine has been also investigated. We now report on the synthesis of two different nanoflowers: Cu nanoflowers and Fe3+ attached Cu nanoflowers and their interaction with two fluorescent probes, anilino-1-naphthalenesulfonic acid (ANS) and Fura 2, and two proteins, human serum albumin (HSA) and thrombin. Nanoflowers did not bind ANS, but bind efficiently to Fura 2 and both proteins. Modification of Cu–NFs by Fe3+ leads to significant changes in their binding capacity to fluorescent probe Fura 2 and both proteins. Their ability to bind fluorescent probe Fura 2 increased eightfold, and their ability to bind HSA and thrombin increased five times. Regarding Fe3+–Cu–NFs, a difference in binding between HSA and thrombin was found that can be explained by their structural features. Our data indicate the possibility of using studied nanoflowers for sorption of fluorescent probes and proteins. [ABSTRACT FROM AUTHOR]

Bi5+ doped Bi2WO6 nanoflowers were prepared for the first time by hydrothermal method using sodium bismuth and sodium tungstate as raw materials. The crystal structure, micromorphology, optical absorption and photoelectrochemical properties of the materials were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, UV–vis spectrum, photocurrent response and electrochemical impedance spectroscopy plots. Using the degradation of Rhodamine B (RhB) under visible light as the reaction model, the effects of Bi5+ doping on the photocatalytic activity of Bi2WO6 nanoflowers were investigated. The results showed that Bi5+ doping reduces the bandgap of Bi2WO6 nanoflowers, and improves the absorption ability of Bi2WO6 nanoflowers in the visible-light region remarkably. The photocatalytic activity of Bi5+ doped Bi2WO6 nanoflowers was promoted significantly, and the degradation efficiency of RhB can reach 96% in 60 min under visible-light irradiation. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H 2 S) is a colorless toxic acidic gas, so the development of gas sensors that can effectively detect H 2 S in the environment is critical to protecting human health. Metal-organic frameworks (MOFs) are emerging as promising template for semiconductor materials in gas sensor technology, offering unique structural advantages for various sensing applications. This study aimed to understand the properties of Indium-doped ZIF-67 nanoflowers by analyzing their crystal structure, surface morphology, and chemical composition. It also investigated the hydrogen sulfide (H 2 S) gas-sensitive properties of these materials to fully comprehend their capabilities and limitations. It is demonstrated that the Co 3 O 4 sensor doped with 5 % In displays excellent stability, gas selectivity, and responsiveness. Specifically, the Co 3 O 4 sensor doped with 5 % In showed a response of 19–50 ppm H 2 S at an operating temperature of 180 °C, which was significantly higher than that of the pure Co 3 O 4 sensor. This is mainly due to the high content of oxygen vacancy (11.26 %). In the 5 % In doped sample, and the relatively large specific surface area (60.58 m2g-1). [ABSTRACT FROM AUTHOR]