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The precise control of size and morphology of photocatalysts through solvothermal methods is a challenge in the basic research of 3‐D titanium dioxide (TiO2) hierarchical structures. This study utilizes the solvothermal method to synthesize N‐involved TiO2 nanoflowers with nanosheet‐assembled structures ranging from microscale (1.3 µm ± 0.2 µm) to nanoscale (200 nm ± 50 nm), achieved by varying the volume fraction (percentage by volume, vol%) of N‐N‐dimethylformamide (DMF) from 0% to 75% in a mixed solution of DMF and isopropanol (IPA). The synthesized TiO2:VFDMF = 0–75% catalyst exhibits good monodispersity and uniform particle size. With increasing DMF volume percentage, the size of TiO2:VFDMF = 0–75% decreased regularly, and the number of nanosheets constructed with a single TiO2:VFDMF = 0–75% particle decreased without any stacking or reassembly occurring. This study monitors the solvothermal processes of DMF 5% and DMF 75%, revealing the changing rules of nanoparticle size and morphology. Furthermore, the photocatalytic degradation of methyl orange shows that TiO2:VFDMF = 50% and TiO2:VFDMF = 75% are structurally stable and exhibit good photocatalytic activity without any noble metal doping. The degradation efficiency reaches 99.9%, and after repeated use, the catalysts demonstrate excellent degradation performance. [ABSTRACT FROM AUTHOR]

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 present study focuses on the elaboration of magnetic nanocomposites by the in situ incorporation of magnetite (Fe3O4) nanoparticles (NPs) with spherical and nanoflower-like morphologies in graphitic carbon nitride (g-C3N4) sheets using two different synthetic routes. Nanomaterials are characterized by TEM, SEM, XRD, FTIR, BET, zetametry, vibrating sample magnetometry, and UV–vis absorption spectroscopy. The decoration of the carbon nitride matrix with the magnetic NPs enhanced optical and textural properties. The influence of the morphology of the magnetic NPs on the adsorptive and photocatalytic properties of the nanocomposites under different pH conditions (4.5, 6.9, and 10.6) was assessed from batch tests to remove methylene blue (MB) from aqueous solutions. In extreme pH conditions, the nanocomposites exhibited lower or equivalent MB removal capacity compared to the pure g-C3N4. However, at neutral medium, the nanocomposite with incorporated Fe3O4 nanoflowers showed a significantly higher removal efficiency (80.7%) due to the combination of a high adsorption capacity and a good photocatalytic activity in this pH region. The proposed nanocomposite is a promising alternative to remove cationic dyes from water by magnetic assistance, since no pH adjustment of the polluted effluent is required, reducing costs and environmental impact in the dyeing industry. [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]

Abstract Nucleotides, such as uridine 5′‐monophosphate (5′‐UMP) and cytidine 5′‐monophosphate (5′‐CMP), are heavily demanded as food additives, dietary supplements, and medicinal intermediates. Although enzymatic phosphorylation is an effective approach to producing these nucleosides, its practical application is challenging due to the need for the expensive enzymes and coenzyme guanosine‐5′‐triphosphate (GTP). Here we prepared biocompatible calcium‐based nanoflowers incorporated with cascade enzymes, uridine‐cytidine kinase (UCK) and acetate kinase (ACK), for the production of nucleotides. The spatial distribution of these enzymes was optimized to maximize their catalytic performances. The most active nanoflowers (Ca3(PO4)2& ACK)& UCK that display the rate‐limiting enzyme UCK on the outer layer were used in a packed‐bed reactor for continuous synthesis of 5′‐UMP and 5′‐CMP. The catalytic performance of the catalyst retained over 80% within 10 h, showing good operational stability.

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]

In this study, we elucidate the synthesis and characterization of molybdenum (Mo) doped zinc oxide (ZnO) nanoflowers (Mo-ZnO@NF) fabricated via a hydrothermal approach, showcasing their potential application in hydrogen generation and dye degradation. The successful synthesis of these nanoflowers is achieved through the deliberate incorporation of Mo ions into the ZnO lattice, yielding a distinctive hierarchical flower-like morphology. Comprehensive structural, morphological, and optical analyses are conducted employing a suite of analytical techniques, encompassing XRD, Raman, FESEM, and UVVisible spectroscopy. XRD analysis confirms the retention of the hexagonal wurtzite crystal structure, accompanied by discernible peak shifts indicative of Mo ion integration. FESEM imaging further elucidates the flower-like architecture of Mo-ZnO, underscoring the intricate morphological features. Photocatalytic assessment reveals the remarkable efficacy of Mo-ZnO@NF, as evidenced by an unprecedented hydrogen evolution rate of 2024mmol/h/g and 97% Methylene Blue (MB) dye degradation within a mere 40-minute timeframe. Furthermore, a comparative investigation between pristine ZnO and varying Mo doping concentrations (ranging from 1% to 5%) underscores the optimal doping concentration of 1% Mo in ZnO. This concentration threshold is shown to engender superior photocatalytic performance, potentially attributed to enhanced charge carrier separation and increased surface area conducive to catalytic reactions. Overall, this study not only advances our understanding of Mo-ZnO@NF nanostructures but also elucidates key insights into optimizing their photocatalytic efficacy for diverse environmental remediation applications. [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]

Nucleotides, such as uridine 5′‐monophosphate (5′‐UMP) and cytidine 5′‐monophosphate (5′‐CMP), are heavily demanded as food additives, dietary supplements, and medicinal intermediates. Although enzymatic phosphorylation is an effective approach to producing these nucleosides, its practical application is challenging due to the need for the expensive enzymes and coenzyme guanosine‐5′‐triphosphate (GTP). Here we prepared biocompatible calcium‐based nanoflowers incorporated with cascade enzymes, uridine‐cytidine kinase (UCK) and acetate kinase (ACK), for the production of nucleotides. The spatial distribution of these enzymes was optimized to maximize their catalytic performances. The most active nanoflowers (Ca3(PO4)2& ACK)& UCK that display the rate‐limiting enzyme UCK on the outer layer were used in a packed‐bed reactor for continuous synthesis of 5′‐UMP and 5′‐CMP. The catalytic performance of the catalyst retained over 80% within 10 h, showing good operational stability. [ABSTRACT FROM AUTHOR]

In this study, we report the structural, optical, and surface properties of copper oxide (CuO) nanostructures that were produced using the chemical co-precipitation process at various specified pH values ranging from 8 to 12. X-ray diffraction, scanning electron microscopy, and elemental analysis (EDX) were used to describe the structural properties of the produced nanostructures, while UV–visible spectroscopy was used to examine their optical properties. The study of X-ray diffractometer patterns indicates the pure phase formation of CuO and this purity loses when pH reach to 13 where the impurities presented in the CuO. scanning electron microscopy images show the structural changes from nanoparticles shape at (pH 8) to nanoflowers shape (pH 10). The absorption band of CuO nanoparticles shows a blue shift with increase of pH. [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]

This study demonstrates the hydrothermal synthesis of 3D flower-like MoS2 nanostructures by varying the heating ramp rate ranging from 1.5 to 5 °C/min. These nanostructures were evaluated for the adsorption and photocatalytic degradation of Rhodamine B (RhB), Methylene Blue (MB), and Tetracycline (TC). Structural and optical properties were characterized using XRD, Raman spectroscopy, FESEM, UV–Vis–NIR spectrophotometry, and XPS. The BET technique assessed surface area, pore size, and volume. Notably, materials synthesized at the slowest heating rate (1.5 °C/min) exhibited superior performance, achieving 98 % degradation of RhB and MB, and 93 % for TC. High adsorption and photocatalytic efficiency were attributed to nanosheets' high density, large specific surface area, zeta potential, and suitable band gap. The study also analyzed the effects of dye concentration and catalyst dosage on RhB degradation, highlighting the synergistic effect of adsorption and photocatalysis in wastewater treatment.

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]

In this study, we elucidate the synthesis and characterization of molybdenum (Mo) doped zinc oxide (ZnO) nanoflowers (Mo-ZnO@NF) fabricated via a hydrothermal approach, showcasing their potential application in hydrogen generation and dye degradation. The successful synthesis of these nanoflowers is achieved through the deliberate incorporation of Mo ions into the ZnO lattice, yielding a distinctive hierarchical flower-like morphology. Comprehensive structural, morphological, and optical analyses are conducted employing a suite of analytical techniques, encompassing XRD, Raman, FESEM, and UV-Visible spectroscopy. XRD analysis confirms the retention of the hexagonal wurtzite crystal structure, accompanied by discernible peak shifts indicative of Mo ion integration. FESEM imaging further elucidates the flower-like architecture of Mo-ZnO, underscoring the intricate morphological features. Photocatalytic assessment reveals the remarkable efficacy of Mo-ZnO@NF, as evidenced by an unprecedented hydrogen evolution rate of 2024 mmol/h/g and 97% Methylene Blue (MB) dye degradation within a mere 40-minute timeframe. Furthermore, a comparative investigation between pristine ZnO and varying Mo doping concentrations (ranging from 1% to 5%) underscores the optimal doping concentration of 1% Mo in ZnO. This concentration threshold is shown to engender superior photocatalytic performance, potentially attributed to enhanced charge carrier separation and increased surface area conducive to catalytic reactions. Overall, this study not only advances our understanding of Mo-ZnO@NF nanostructures but also elucidates key insights into optimizing their photocatalytic efficacy for diverse environmental remediation applications.

Herein, we investigate the effects of temperature and thiourea addition rate on the synthesis of copper sulfide nanoparticles (CuS NPs) via a chemical co-precipitation method, exploring their impact on the size and morphology of CuS NPs. Our systematic approach resulted in the successful synthesis of CuS NPs with significantly smaller nanoflower sizes than previously reported in the literature, providing insights into the nucleation and growth mechanisms under various synthesis conditions. Furthermore, the photocatalytic activity of the synthesized CuS NPs with three types of distinctive morphologies, namely, nanoflowers with 50 nm diameter (F-50), nanoflowers with 200 nm diameter, and nanogravels with 50 nm diameter, is comparatively analyzed. Notably, the F-50 exhibits a superior photocatalytic performance compared to the other samples, demonstrating the considerable influence of the NP size and morphology on their functional properties. Furthermore, the antibacterial property of the small CuS nanoflowers is examined using an antibacterial film fabricated by coating the NPs on a polyethylene terephthalate substrate, which is widely used as a protective or packaging film in various industries because of its transparency and flexibility. The antibacterial film can be used to kill both gram-positive and -negative bacteria effectively. This research contributes significantly to the understanding and optimization of CuS NP synthesis and application, emphasizing the potential of small-sized nanoflower CuS NPs in photocatalysis and antibacterial applications.

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]

For the synthesis of organic@inorganic hybrid nanoflowers (hNFS), instead of expensive biomolecules such as DNA, enzyme, and protein, the Cucumis sativus (cucumber) leaf extract was used as an organic component in this study. In the PBS buffer with different pH (5, 7.4, and 9), hNFs were synthesized using extract with different volumes, but these parameters (concentration and pH) significantly affected the morphological characteristics of hNFs. Morphologies, elemental compositions, and organic groups that play key role in the synthesis of hNFs were detailed using FE-SEM, EDX, and FT-IR analyses, respectively. hNFs with ideal flower morphology (synthesized at pH 7.4 with 1 ml extract) showed antimicrobial activity against Staphylococcus aureus and Escherichia coli strains. Antimicrobial activity against strains and peroxidase-like activity against guaiacol of hNFs are explained by Fenton mechanisms. [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]

In this study, detection sensitivity of the conventional flame atomic absorption spectrophotometer (FAAS) for the determination of manganese (Mn2+) was enhanced by employing a preconcentration method from wastewater samples. Flower-shaped Ni(OH)2 nanomaterials were synthesized and used as sorbent material in preconcentration procedure. With the aim of attaining optimum experimental conditions, effective parameters of extraction method were optimized and these included pH of buffer solution, desorption solvent concentration and volume, mixing type and period, nanoflower amount, and sample volume. The detection limit of the optimized method was determined to be 2.2 μg L−1, and this correlated to about 41-fold enhancement in detection power relative to direct FAAS measurement. Domestic wastewater was used to test the feasibility of the proposed method to real samples by performing spike recovery experiments. The wastewater sample was spiked at four different concentrations of manganese, and the percent recoveries determined were in the range of 95–120%. [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.

The nanoflowers and nanoblocks of Fe-doped ZnO (i.e. ZnO doped with 0, 1, 2, 3, 4 and 5% Fe) were synthesised by co-precipitation technique. XRD analysis showed that the samples have wurtzite structure containing mostly Fe3+ in the samples with 1% Fe and a mixture of Fe3+ and Fe2+ in the samples with higher amount of dopant. Morphology transformations from nanoflowers to nanoblocks, then into a combination of nanoflowers and nanoblocks were observed. The UV analysis identified the presence of multi-absorption regions in the doped samples. Due to the elevated Fe2+ concentration, the band gap of the 5% doped nanoblocks expanded and behaved irregularly. The room temperature photoluminescence characteristics of the Fe-doped ZnO nanostructures were determined. It was found that, in addition to the detected peaks in the yellow and red regions, the sample doped with 1%Fe shows two peaks in the blue region which could be interesting for multifunctional applications in the field of optoelectronics.

The industrial application of free enzyme is limited due to its high cost, poor operational stability and difficult reuse. Immobilization on carrier is an effective way to overcome the limitation. Nanozyme immobilization technology has emerged in the past 10 years, which is an emerging technology with great potential. At present, immobilized enzymes have been widely used in several fields such as food, medical treatment, and environmental treatment. This article systematically summarizes the latest progress in the research and application of immobilized enzymes based on three new nanomaterials (protein-inorganic hybrid nanoflowers, metal organic frameworks and nanogels), comprehensively compares the advantages and disadvantages of the three nanomaterials, analyzes and summarizes their respective applicable enzymes, and finally points out that cascade enzyme immobilization and the development of new immobilized materials are the future trend for the development of immobilized enzymes.

Enzymes reign over inorganic and organometallic catalysts in aspects of conversion and product selectivity. Natural products are always produced in small quantities and to mimic such biological setups for large-scale production requires harsh solvent systems and elevated temperatures to promote the reaction rates, conditions known to denature most enzymes. Immobilization of enzymes has been used to surpass such challenges in addition to allowing single and multiple enzyme reactions in contrasting reaction media. This review addresses the different techniques used to support and stabilize biocatalysts. Silica is the oldest support material used to encapsulate/immobilize enzymes and like all immobilization techniques, it significantly increases the thermal stability, extreme pH tolerance, recyclability and lifespan of biocatalysts. Immobilization supports with reactive functional groups such as metal salts, metal-, covalent- and hydrogen-bonded organic frameworks work well with enzymes that exhibit hydrophobic tolerance. Bienzymatic immobilization by one support system or the use of multiple supports for a single enzyme and further enhancement of immobilized enzymes to increase activity is possible. Some immobilization support systems such as silica and enzyme hybrid nanoflowers work well with both hydrophilic/hydrophobic and metal-free/metal-containing enzymes. Solid supports such as natural fibers and metal salts, for example, polyoxometalate hybrids stretch the enzyme’s thermal stability further (>60 °C) and also accommodate more enzyme particles.

Bimetallic materials show superior properties over monometallic systems due to their synergistic effect. Herein, bimetallic CoNi nanoflowers are synthesized by a simple method and characterized via various characterization techniques such as powder X‐ray diffraction (PXRD), scanning electron microscopy, high‐resolution transmission electron microscopy, X‐ray photoelectron spectroscopy, etc. PXRD results confirm the formation of face‐centered cubic CoNi nanoflowers and morphological studies confirm the flower‐like structure of CoNi. Bimetallic CoNi nanoflowers utilized for supercapacitor applications and the effect of electrolyte cations (K+, Na+, Li+) are studied. The results reveal that LiOH shows excellent capacitance of 729.52 F g−1 (66.83 mAh g−1) at 1 A g−1. The cyclic stability of CoNi nanoflower is estimated as ≈100% after 10 000 cycles which signifies the exceptional long‐term utility of the electrode for practical application. Further, the asymmetric device is fabricated which shows the capacitance of 66.61 F g−1 and the commercial light‐emitting diode (1.8 V) delivers high energy density and power density, that is, 18.13 Wh kg−1 at 699.84 W kg−1. The nanoflower exhibits battery–supercapacitor‐type behavior with rapid charge/discharge capability with a binder‐free and additive‐free approach. [ABSTRACT FROM AUTHOR]

Heavy metal ions threaten public health and marine life; thus, removal of heavy metals is essential for the environment. Bi2S3 nanostructures are active materials which used in various applications. In this work, we produced Bi2S3 nanoflowers using hydrothermal synthesis and assessed their Cd2+ ions removal capability. Structural properties of the Bi2S3 nanoflowers were assessed by various like scanning electron microscopy, X-ray diffraction. Chemical characteristics of the materials were confirmed using energy dispersive X-ray spectra. Different parameters affecting the Cd2+ ion recovery was worked some of which are adsorbent amount, Cd2+ ion concentration, pH, adsorbent time, eluent type and amount, etc. For cadmium, the optimum pH was determined 8.0 for 1 M HNO3 eluent. Optimum adsorbent amount was determined as 150 mg while optimum recovery duration was found as 30 min. Bi2S3 nanoparticles managed to achieve 99.3% Cd2+ recovery rate in 5 mL eluent volume, for optimum condition. The adsorption capacity of the Bi2S3 nanoflowers was found to be promising and therefore, it was illustrated that Bi2S3 nanoflowers are good candidates as sorbent for water remediation applications. [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 copper doped ZnO (CuxZn1-xO, where x = 0, 0.01, 0.02, 0.04, 0.05) nanoflowers were produced by using co-precipitation process. Hexagonal wurtzite nanocrystalline phase of both pure and Cu-doped samples was confirmed by X-ray diffraction analysis. Field emission scanning electron microscopy results confirmed the emergence of fully dispersed nanoflower like morphologies in the Cu-doped ZnO and uniform dispersion of particles. Band gap energies of the prepared samples were calculated using the Tauc’s plot. All of the generated samples’ room temperature photoluminescent spectra show two emission peaks, one excitonic peak in the UV region and another broad defect level peak in the visible area. The yellow and green luminescence characteristics of both pure and doped samples were analysed via the PL spectra in visible light region, making them appropriate for optoelectronic applications. The antibacterial potential of the produced nanostructures against the bacterial strains of Enterococcus Faecalis (gram positive) and Pseudomonas Aeruginosa (gram negative) were assessed. When compared to the pure ZnO nanostructures, the doped samples exhibit enhanced antibacterial activity. For the samples with 5 at.%Cu, the greatest zone of inhibition against Pseudomonas Aeruginosa was noted to be 25mm. For the samples doped with 5 at.% Cu, the largest zone of inhibition against Enterococcus Faecalis was 21mm. The findings indicate that the obtained samples have higher antibacterial potential against gram negative than gram positive bacteria. The prepared doped ZnO nanoflowers were therefore recommended as excellent green nanophosphors for the production of white LEDs and effective nanoantibiotics against gram-negative bacteria.

Since WO3 is a relatively abundant metal oxide and features the ability to absorb in the visible spectrum, this non-toxic semiconductor is a promising photocatalyst among sustainable materials. These properties have delivered intriguing catalytic results in the conversion of methane to methanol; however, initial investigations indicate low photocatalytic efficiency resulting from fast recombination of photogenerated charges. To explore this aspect of inefficiency, five different morphologies of WO3 consisting of micron, nanopowder, rods, wires, and flowers were obtained and characterized. In addition, several electron capture agents/oxidizers were investigated as a means of improving the separation of photogenerated charges. The photocatalytic activity of different morphologies was assessed via CH3OH formation rates. Based on our results, WO3 flowers produced the highest methanol productivity (38.17 ± 3.24 µmol/g-h) when 2 mM H2O2 was present, which is approximately four times higher in the absence of H2O2. This higher methanol production has been attributed to the unique structure-related properties of the flower-like structure. Photoluminescence emission spectra and diffuse reflectance data reveal that flower structures are highly catalytic due to their reduced electron/hole recombination and multiple light reflections via petal-like hollow chambers.

The fabrication of hybrid protein-Cu3(PO4)2 nanoflowers (NFs) via an intermediate toroidal structure is dramatically accelerated under shear using a vortex fluidic device (VFD), which possesses a rapidly rotating angled tube. As-prepared laccase NFs (LNFs) exhibit ≈1.8-fold increase in catalytic activity compared to free laccase under diffusion control, which is further enhanced by ≈ 2.9-fold for the catalysis under shear in the VFD. A new LNF immobilization platform, LNF@silica incorporated in a VFD tube, was subsequently developed by mixing the LNFs for 15 min with silica hydrogel resulting in gelation along the VFD tube surface. The resulting LNFs@silica coating is highly stable and reusable, which allows a dramatic 16-fold enhancement in catalytic rates relative to LNF@silica inside glass vials. Ultraviolet-visible spectroscopy-based real-time monitoring within the LNFs@silica-coated tube reveals good stability of the coating in continuous flow processing. The results demonstrate the utility of the VFD microfluidic platform, further highlighting its ability to control chemical and enzymatic processes.

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]

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Hybrid organic‐inorganic nanoflowers (NFs) have recently emerged as a critical tool in enhancing the stability and activity of biomolecules due to their expansive surface area and porosity. The delicate petal‐like features of NFs offer innumerable sites for biomolecule adsorption, including but not limited to proteins, amino acids, and enzymes. Cu‐BTC, a copper‐based Metal‐Organic Framework (MOF) has been hindered in its potential for diverse applications by its instability in humid and aqueous conditions. To overcome this limitation, this study explores the stabilization of Cu‐BTC via the mineralization of its surface with the formation of copper phosphate nanoflowers (NFs). To initiate the mineralization process and provide a template for the growth of the NFs, a physiologically rich amino acid medium is employed. The inclusion of amino acids in the RPMI medium played a crucial role in the preservation of the Cu‐BTC hierarchical structure by facilitating the self‐assembly of copper phosphate nanoflowers on its surface, thereby producing a Cu‐BTC@Cu3(PO4)2 core‐shell structure. The innovative mechanism behind the formation of copper phosphate nanoflowers in this study and its consequential stabilization of the Cu‐BTC MOF structure underscore its novel nature. [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]

Zinc oxide (ZnO) nanostructure was successfully synthesized on an alumina substrate by the hydrothermal method. The hydrothermal method consists of two stages: the preparation of seeding layers and the growth of ZnO nanostructures. 0.4 M Zinc Acetate Dihydrate (Zn(CH3COO)2·2H2O) and 3 M Sodium Hydroxide (NaOH) were used as precursors. The hydrothermal process was carried out at 90 °C for 4 hours. Morphological characterization of ZnO nanostructures was conducted by using Scanning Electron Microscope (SEM). The result produces a diameter of 60-80 nm and a length of 600-800 nm in the form of nanoflowers. The crystal and crystalline structure were studied with XRD, and it was shown that the ZnO nanostructure is a wurtzite structure in the form of a hexagonal shape and has a crystallite size of 59 nm. After conducting electrical characterization, it was shown that the current is directly proportional to the voltage, forming an ohmic contact curve. ZnO nanostructures have the potential to be applied as a gas sensor since the good response indicated the presence of butane gas. It is clarified that the nanostructure with a flow rate of 200 mL/min has a change in resistance of 0.17 MΩ/s with a recovery time of 30 seconds when it is exposed to butane gas for one minute. ZnO nanostructures also have a sensitivity change of 0.000495 MΩ/mL in the gas flow rate range of 50-250 mL/min. [ABSTRACT FROM AUTHOR]

The formation of nonspherical anisotropic nanoparticles having a large surface area by pulsed laser ablation in liquids (PLAL) still remains a challenge. In this work, to expand the capabilities of the PLAL technique, an approach was developed based on pulsed laser ablation in liquids with an external voltage applied to the target. This approach allowed shape-controlled preparation of nonspherical ZnO/C composite nanomaterials providing additional possibilities for tuning of the particles' morphology that was found to depend on the applied voltage and polarity. The positive polarity on the Zn target allowed obtaining nanodisk structures, whereas application of negative polarity to the target enabled the formation of flower-like nanostructures proven by scanning (SEM) and transmission electron microscopy (TEM) studies. The optimal conditions for the nanoflower formation were found with the voltage set to be 200 V. A time-resolved imaging technique was applied to study plasma propagation evolution and lifetime that allows suggesting the mechanisms of nanoflower formation. Furthermore, utilizing the developed approach in a carbon nanoparticle colloid, sponge-like composites were obtained having a developed surface that showed promising capacitance and charge storage behavior in preliminary electrochemical tests. The ZnO/C composite structures were evidenced by SEM and TEM studies as well as by EDX mapping, X-ray diffraction, Raman, infrared, and optical absorption spectroscopy measurements. In addition, the production of particles in the presence of an electric field leads to the deposition of the formed nanostructures on the cathode surface that can serve as a tool for assembling the resulting particles into ordered structures for subsequent supercapacitor applications. [ABSTRACT FROM AUTHOR]

As the current pandemic has shown, lateral flow assays (LFAs) are a prime example of point-of-care devices enabling quick testing at an affordable price. However, their ease of use undeniably affects their sensitivity, making them less sensitive than other multi-step and time-consuming diagnostic assays, such as polymerase chain reactions and enzyme-linked immunosorbent assays. A possible solution to overcome this lack of sensitivity is the exploitation of bottom-up approaches to synthesize nanomaterials with outstanding properties for use as colorimetric labels in LFAs, that is, using nanoparticles with better optical capabilities to improve the generation of the colorimetric signal and the overall sensitivity of LFAs. Following this strategy, we rationally optimized the synthesis of gold and iridium oxide nanoflowers (Au–IrO2 NFs) to enhance their physical–chemical properties as colorimetric labels in LFAs. Specifically, we were able to rationally control their size (from 155 to 53 nm in diameter) in order to guarantee an optimal flow along the different pads of a LFA. Moreover, thanks to their superior plasmonic behavior (compared to standard AuNPs), we could achieve an 8.5-fold lower limit of detection (down to 1.2 ng/mL) for human immunoglobulin G (HIgG) than standard LFAs (10.1 ng/mL). Therefore, due to their optical and redox properties, bioconjugation capabilities, and synergic combination of the individual components, Au–IrO2 NFs appear as potential candidates for the next generation of optical LFAs. [ABSTRACT FROM AUTHOR]