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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]

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]

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]

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]

• Sr x Bi 2-x S 3 nanoflowers have been prepared by facile hydrothermal method. • Sr x Bi 2-x S 3 nanoflowers thermally stable up to 645 °C. • 5 mg of Sr 0.06 Bi 1.94 S 3 catalyst exhibit degradation efficiency ∼ 92 % for 10 ppm RhB. • Pseudo 1st and zeroth order kinetics obey in dark and visible light, respectively. Rhodamine-B is a hazardous pollutant used in textile industries that has adverse effects on humans and aquatic life. So, there is need to develop cost-effective and efficient photocatalysts. Sr x Bi 2-x S 3 nanoflowers with varying Sr contents have been synthesized using hydrothermal method and have been studied by TGA, XRD, Rietveld refinement, UV-DRS, FESEM with EDX, PL and Zeta potential. The photocatalytic performance has been estimated by degrading RhB pollutants under visible light illumination. The morphology of the prepared Sr x Bi 2-x S 3 nanoparticles has been observed to be flower-like. They are stable up to 645 °C as assessed by TGA. Their Rietveld refinement revealed the orthorhombic crystal structure. E g determined using DRS falls in the range of 1.45 eV to 1.37 eV, while PL studies corroborate decreased e −- h + pairs recombination in Sr doped samples compared to pure. The negative value of surface potential ascertained using zeta potential makes them suitable for cationic dye. The impact of dopant concentration on RhB under visible light exposure reveals x = 0.06 exhibits the highest degradation efficiency (η ∼ 92 %) in 240 min utilizing 5 mg/100 ml solution of 10 ppm dye concentration. The adsorption kinetic model is of 1st order, while photodegradation kinetics is governed by Zeroth order model. [Display omitted] [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]

Self-assembling carrier-free nanodrugs are attractive agents because they accumulate at tumor by an enhanced permeability and retention (EPR) effect without introduction of inactive substances, and some nanodrugs can alter the immune environment. We synthesized a peptidyl arginine deiminase 4 (PAD4) molecular inhibitor, ZD-E-1M. It could self-assembled into nanodrug ZD-E-1. Using confocal laser scanning microscopy, we observed its cellular colocalization, PAD4 activity and neutrophil extracellular traps (NETs) formation. The populations of immune cells and expression of immune-related proteins were determined by single-cell mass cytometry. ZD-E-1 formed nanoflowers in an acidic environment, whereas it formed nanospheres at pH 7.4. Accumulation of ZD-E-1 at tumor was pH-responsive because of its pH-dependent differences in the size and shape. It could enter the nucleus and bind to PAD4 to prolong the intracellular retention time. In mice, ZD-E-1 inhibited tumor growth and metastasis by inhibiting PAD4 activity and NETs formation. Besides, ZD-E-1 could regulate the ratio of immune cells in LLC tumor-bearing mice. Immunosuppressive proteins like LAG3 were suppressed, while IFN- γ and TNF- α as stimulators of tumor immune response were upregulated. Overall, ZD-E-1 is a self-assembling carrier-free nanodrug that responds to pH, inhibits PAD4 activity, blocks neutrophil extracellular traps formation, and improves the tumor immune microenvironment. ZD-E-1 targets tumors by binding PAD4 in response to pH and the enhanced permeability and retention (EPR) effect. It selectively inhibited tumor growth and metastasis by blocking NETs formation and improving the tumor immune microenvironment. [Display omitted] [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]

2-O-(α- d -glucopyranosyl)-sn-glycerol (2-αGG) has been applied in the food industry due to its numerous physiological benefits. The synthesis of 2-αGG can be achieved through a cascade catalytic reaction involving sucrose phosphorylase (SP) and 2-O-α-glucosylglycerol phosphorylase (GGP). However, the low substrate transfer rates between free enzymes have hindered the efficiency of 2-αGG synthesis. To address this issue, a novel technology was developed to prepare sequential multi-enzyme nanoflowers via chemical crosslinking and protein assembly, thus overcoming diffusion limitations. Specifically, spatially sequential co-immobilized enzymes, referred to as SP-GGP@Cap, were created through the targeted assembly of Bifidobacterium adolescentis SP and Marinobacter adhaerens GGP on Ca2+. This assembly was facilitated by the spontaneous protein reaction between SpyTag and SpyCatcher. Compared to free SP-GGP, SP-GGP@Cap demonstrated improved thermal and pH stability. Moreover, SP-GGP@Cap enhanced the biosynthesis of 2-αGG, achieving a relative concentration of 98 %. Additionally, it retained the ability to catalyze the substrate to yield 61 % relative concentration of 2-αGG even after ten cycles of recycling. This study presents a strategy for the spatially sequential co-immobilization of multiple enzymes in a confined environment and provides an exceptional biocatalyst for the potential industrial production of 2-αGG. [Display omitted] • A spatially sequential multi-enzyme immobilization strategy was provided. • SP-GGP@Cap was constructed by SP and GGP via the above strategy. • SP-GGP@Cap showed excellent thermal and pH stability than free SP-GGP. • SP-GGP@Cap enabled the biosynthesis of 2-αGG, with a relative concentration of 98 %. • SP-GGP@Cap could catalyze the substrate to synthesize a 61 % relative concentration of 2-αGG after recycling ten times. [ABSTRACT FROM AUTHOR]

• Hydrothermal synthesis was used to create MoSe2-NFs easily and sustainably. • The investigation focused on the covalent immobilization of α -amylase onto functionalized MoSe 2 -NFs. • The Box-Behnken design was utilized to optimize the parameters, leading to an immobilization efficiency of 87.33%. • Immobilization was confirmed by XRD, Raman, SEM, TEM, FT-IR, AFM, and Fluorescence microscopy. • Immobilization improves enzyme pH, temperature, and stability. The current study presents the application of molybdenum diselenide nanoflowers (MoSe 2 -NFs) as an innovative substrate for immobilizing α -amylase by glutaraldehyde activation. This approach results in the development of a nanobiocatalyst that exhibits remarkable advantages compared to a standalone enzyme. Several physical methods, such as fluorescence microscopy, FT-IR, SEM, TEM, XRD, AFM, and Raman spectroscopy, were used to confirm that α -amylase was successfully attached to MoSe2-NFs. By employing the Box-Behnken design of the RSM, the parameters were optimized, resulting in an immobilization efficiency of roughly 87.33%. The immobilized variant of α-amylase demonstrated superior thermostability, pH stability, reusability, and storage stability in comparison to the soluble enzyme. The catalytic activity of α -amylase was highest when immobilized on MoSe 2 -NFs at the same pH and temperature as the soluble enzyme. However, there was an expansion in the range of parameters in which this activity was observed. Furthermore, the immobilized enzyme exhibited a retention of nearly 80% residual activity following 12 successive reuses. The immobilized enzyme exhibited around 82% residual activity after being stored for 120 days. It is possible that the immobilization process changed the Michaelis-Menten constant, which means that the substrate could no longer reach certain active sites on the enzyme because it had become longer. The study's findings suggest that the α -amylase-MoSe 2 -NFs system could be useful in industry because it can work in a wider range of temperature and pH conditions. Furthermore, the intrinsic non-toxic characteristics of the matrix, along with its ability to be kept for prolonged periods and recycled, render nano biocatalysts very well-suited for the effective synthesis of maltose in the food and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

Organic-inorganic hybrid nanoflowers (HNFs) of laccase@Zn 3 (PO 4) 2 were fabricated through a facile, simple, and rapid one-step strategy. In this process, laccase was involved in nucleation and fast anisotropic growth reactions with Zn (II) and phosphate ions. The average pore size of the prepared HNFs was 54.5 nm, and its BET-specific surface area was 59.5 m2 g−1. In comparison with the free laccase, the entrapped enzyme activity in the constructed HNFs was 86.4%. In addition, the hybrid biocatalyst displayed a maximum rate of reaction (V max) of 1640.2 ± 3.6 μmol min−1 with respect to the native enzyme. The constructed HNFs maintained 45.1% and 60% of the original laccase activity after 12 successive reusability cycles and 30 days of storage at 4 °C, respectively. The as-obtained HNFs demonstrated a high bioremoval percentage of Direct blue-71 (94.1%) within a 10-h-treatment at 40 °C and 15 mg l−1 of the dye concentration. The pseudo-first order and second order were the best-fitted kinetic models for the dye removal using Zn 3 (PO 4) 2 nanoflakes and the fabricated HNFs, respectively. Besides, liquid chromatography-mass spectrometry (LC-MS) revealed biotransformation of the dye into less toxic metabolites as verified by testing on some bacterial strains. • A novel strategy was established for instant synthesis of hybrid nanoflowers. • A mechanism was proposed for synthesis of laccase-zinc hybrid nanoflowers. • The nanoflowers maintained 45% of their initial activity upon 12 successive cycles. • A remarkable storage stability was achieved by the hybrid nanoflowers. • Degradation of Direct blue-71 was 94% after 10 h treatment with the biocatalyst. [ABSTRACT FROM AUTHOR]

Since the use of diverse synthesis approaches can induce the variation in the density of active sites, which impacts electrocatalytic performance, the strategy utilized to fabricate the electrode materials for energy devices is just as important as the materials themselves. Herein, porous NiFe-oxide nanoflowers (NiFe-NFs) and macroparticles (NiFe-MPs) and corresponding S-doped NiFe-oxide nanoflowers (NiFeS-NFs) and macroparticles (NiFeS-MPs) were fabricated using facile co-precipitation and hydrothermal-sulfurization strategies, respectively. The prepared NiFe-NFs, NiFeS-NFs, NiFe-MPs, and NiFeS-MPs materials were investigated for their electrocatalytic HER in 1 M KOH electrolyte. The results indicated that NiFe-NFs displayed an overpotential of 177 mV @ 10 mA/cm2 for HER, whereas the NiFe-MPs, having similar composition, exhibited a high HER overpotential of 187 mV @ 10 mA/cm2. The enhanced HER catalytic performance of NiFe-NFs was attributed to the extensive exposure of active sites at the edges and vertices of nanocubes in the NFs-architecture. Moreover, after sulfurization, NiFeS-NFs and NiFeS-MPs demonstrated a considerable enhancement in their HER activity (54 mV and 152 mV @ 10 mA/cm2, respectively) as compared to un-sulfurized materials, which can be attributed to the enhanced conductivity of materials after S-doping, as supported by theoretical studies. Further, the capacitance experiments showed a significant increment in specific capacitances of NFs and MPs after sulfurization, from 69 to 604 F/g and from 185 to 514 F/g, respectively. This work shows that morphological and compositional changes in metal oxide-based materials may considerably enhance their catalytic activity and capacitance. [Display omitted] • A facile strategy is developed to prepare bimetal oxides/sulfer doped bimetal oxides. • Prepared S-doped/undoped NiFe-oxides possessed nanoflowers/macroparticles morphologies. • Prepared NiFeS-oxide with nanoflowers morphology showed excellent OER and HER. • Prepared nanoflowers type NiFeS-oxide exhibited remarkable charge storage capacilty. [ABSTRACT FROM AUTHOR]

Nowadays, there is a great demand for low-cost and highly active electrocatalyst for the production of clean renewable energy. However, most of the electrocatalysts are noble metal-based which are very costly and unstable. To counter this, electrochemical water splitting in energy storage systems is been widely applied, using non-noble metal-based nanostructured electrocatalysts. In this work, a novel noble metal-free MoSe 2 –Ni(OH) 2 nanocomposite electrocatalyst is synthesized using a multi-step hydrothermal technique for efficient hydrogen evolution reaction (HER). The morphology, structural, chemical composition, and functional features of the synthesized nanomaterials were characterized using different techniques that include scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), and Raman analysis. The new developed MoSe 2 –Ni(OH) 2 nanocomposite combines a high active surface area with a high chemical stability, generating a novel material with a synergistic effect that enhances water splitting process performance. Thus, an outstanding low Tafel slope of 54 mV dec−1 is accomplished in the hydrogen evolution reaction. [Display omitted] • MoSe 2 –Ni(OH) 2 nanocomposite is used for the first time for HER. • MoSe 2 –Ni(OH) 2 shows higher activity for HER compared to its pristine counter parts. • High catalytic activity of MoSe 2 –Ni(OH) 2 is due to a synergistic effect. • MoSe 2 –Ni(OH) 2 electrocatalyst is a novel alternative for green hydrogen generation. [ABSTRACT FROM AUTHOR]

In this work, we employed a simple and cost-effective chemical route to obtain a highly stable and efficient quaternary mesoporous 3D nanoflower-like NiCuCo 2 S 4 nanocomposite for supercapacitor applications. The NiCuCo 2 S 4 composite exhibited a mixture of NiCo 2 S 4 and CuCo 2 S 4 phases, confirming the formation a quaternary NiCuCo 2 S 4 thin film. A surface morphological analysis revealed the unique nanoflower-like nanostructure of the annealed composite. The electrochemical analysis of the NiCuCo 2 S 4 electrode demonstrated a high specific capacity (Cs) of 414 mAh g−1 at a lower scan rate of 10 mV s−1 and a superior cycling stability up to 3000 cycles. A solid-state hybrid supercapacitor (SHS) was also constructed by the NiCuCo 2 S 4 and AC powder as positive and negative electrodes, respectively. The NiCuCo 2 S 4 //AC hybrid cell produced a high Cs, energy density, and power density of 159 F g−1, 35.19 Wh kg−1, and 0.66 kW kg−1, respectively at a current density of 10 mA with good cycling stability. The results demonstrated that the fabrication process is effective for the development of a novel quaternary transition metal sulfide (TMS) electrode. [ABSTRACT FROM AUTHOR]

A novel oxygen reduction reaction (ORR) electrocatalyst silver@platinum-cobalt-rGO nanoflower (Ag@PtCo-rGO NFs) is prepared by hydrothermal reduction method. The formation of silver chloride likes elm leaf microstructure in the reaction process, performing as a template. The Ag@PtCo-rGO NFs exhibit excellent electrocatalytic activity, whose specific activity is 9 times higher than that of commercial Pt/C. More importantly, Ag@PtCo-rGO NFs demonstrate excellent durability than JM Pt/C for ORR in acid media, as evidenced by accelerated durability test after 40,000 cycles. These excellent performances can be attributed to the special structure, atomic steps and synergistic effect between Pt, Ag and Co. The density functional theory calculation shows that Ag@PtCo has the best activity, which is related to the transition state for O–O bond. This work proposes a promising pathway for the synthesis of surfactant-free nanoflowers structure catalysts with high catalytic performance and low cost. [Display omitted] • This method prepares nanoflowers without external templates and surfactants. • The SA is 9 times larger than that of commercial Pt/C. • The catalysts exhibit excellent durability after 40,000 cycles. [ABSTRACT FROM AUTHOR]

• A novel adsorbent was successfully synthesized based on the MnCoFe-LDH/Ni-MOF nanocomposite-coated hollow fiber membrane. • The use of centrifuge, vortex, and stirrer were eliminated which, made the extraction process greener, quicker, and easier. • Effective parameters on the extraction efficiency of the analyte were optimized by central composite design method. • The successful extraction of amaranth dye from real samples demonstrated the applicability of the proposed adsorbent. In the present study, the new composite based on MnCoFe-LDH nanoflower/Ni-MOF/ hollow fiber membrane (HFM) was synthesized in such a way that first MnCoFe-LDH and Ni-MOF nanoparticles were synthesized separately, then converted into a composite and finally coated on the surface of the HFM. The final composite was characterized using FT-IR, XRD, SEM, and EDX analysis and applied as a promising and effective sorbent for the solid-phase microextraction of amaranth dye (as a model analyte) in various water and food samples, followed by spectrophotometric analysis. It should be noted that two main driving forces for conducting the extraction process are the electrostatic and π-π interactions between the surface of the adsorbent and the analyte molecule. By using this proposed adsorbent, the requirement for using a centrifuge for phase separation was eliminated. Furthermore, there was no necessity to use the vortex or the stirrer to carry out the adsorption and desorption steps, and only by hand-shaking of the sample solution, high extraction recovery was achieved. These advantages made the extraction process greener, quicker, and easier. Optimizations of all parameters affecting the proposed method (such as pH, sample solution, HFM size, adsorption time, and desorption time) were done using the central composite design methodology. The findings indicate that the calibration graphs exhibited linearity in the range of 20.0–1000 µg/L, with the limit of detection of 5.6 µg/L, the limit of quantification of 17.2 µg/L, and the correlation coefficient of 0.9981 for the model analyte. Furthermore, the relative recovery was obtained in the range of 93.6–101 %. In addition, intra-day RSD, inter-day RSD, and preconcentration factor (PF) were achieved at 3.8, 6.9, and 30, respectively. The suggested sorbent was successfully synthesized and applied for effective solid-phase microextraction of amaranth dye in different real samples. [ABSTRACT FROM AUTHOR]

Power density and overall-cell polarization curves of GL-MoS 2 -CC/MFC, GL-MoS 2 -SSFF/MFC, CC/MFC, and SSFF/MFC. [Display omitted] • One-step hydrothermal method was proposed to synthesize graphene-like MoS 2 nanoflowers. • Graphene-like MoS 2 nanoflowers were used to modify microbial fuel cell anodes. • The method and the nanoflowers modification were proved to be simple, effective and of low cost. Anode, usually with limited specific surface area, poor biocompatibility and high-cost materials, is still the key obstacle for conventional dual-chamber microbial fuel cell (MFC)'s wide application. To combat this challenge, graphene-like molybdenum disulfide (GL-MoS 2) nanoflowers with a lateral size 200–300 nm are successfully synthesized via a simple one-step hydrothermal method and are used to modify MFC anodes. The experimental results show that GL-MoS 2 nanoflowers modified carbon cloth (CC) and stainless-steel fiber felt (SSFF) anode obtains their maximum power density of 960.4 mW·m−2 and 713.6 mW·m−2 which are 1.7 and 3.6 times of their unmodified counterparts, respectively, which indicates that the modification not only can offer large specific surface area and good biocompatibility for biofilm growth, but also makes the anode surface more accessible for microbes' colonization and substrate transfer and thus reduces polarization loss considerably. The graphene-like materials, especially those like GL-MoS 2 , are promising materials for excellent and cost-effective anode modification. [ABSTRACT FROM AUTHOR]

Pistacia Atlantica biomass was utilized as an activated carbon precursor for the preparation of copper oxide/activated carbon (CuO/AC) nanocomposites and the electrochemical hydrogen storage (EHS) capacities of copper oxide with different morphologies and provided nanocomposites were studied. Further, the influence of copper oxide pores size upon the EHS capacity was studied through chronopotentiometry system. Under 1 mA current, the discharge capacities of CuO nanoflowers (CuO nf), CuO nanoparticles (CuO np), Pistacia Atlantica activated carbon (AC), copper oxide nanoflower/activated carbon (CuO nf /AC), and copper oxide nanoparticle/activated carbon (CuO np /AC) were reached to 650, 850, 1200, 2000, and 3000 mAh/g after 25 cycles, respectively. Outcomes reveal that the coating of copper oxide upon the AC with different pores size leads to get better discharge capacity. Therefore, produced nanostructures with inexpensive and simple manner can be utilized for EHS and can be applied as Renew. Energy to reduce the use of fossil fuels. Image 1 • Preparation of CuO/ Pistacia Atlantica based-AC nanocomposites. • Investigation of CuO pores size influence on the electrochemical hydrogen storage. • The coating via CuO with different pores size leads to different discharge capacity. • The discharge capacity of CuO np /AC is greater than CuO nf /AC after 25 cycles. [ABSTRACT FROM AUTHOR]

Electrode materials with high energy and power density are mostly essential to overcome traditional fossil fuel use. Herein, we demonstrate the synthesis of Au decorated self-assembled SnO 2 nanoflowers consisting of nanorods by a cost-effective and eco-friendly solvothermal process. The as-synthesized SnO 2 based materials were employed as electrode material in the energy storage system, which delivered considerably high specific capacitance of 634.3 F/g at a current density of 1 A/g. The electrode material also exhibits excellent cycle stability of 83.52% after 4000 galvanostatic charge–discharge (GCD) cycles. The high specific capacitive value is attributed to the hybrid performance of battery and supercapacitor, more active sites, and higher surface area. A solid state asymmetry device was fabricated using Au–SnO 2 and activated carbon (AC) as positive and negative electrodes. The asymmetry device shows an excellent energy density of 168.9 Wh/kg at a power density of 1 kW/kg with an applied current density of 1 A/g. Image 1 • Facile and one-pot synthesis of Au–SnO 2 nanocomposite. • Au–SnO 2 nanocomposite delivered high specific capacitance of 634.4 F/g at 1 A/g. • ASC device exhibits an energy density of 168.9 Wh/kg at a power density of 1 kW/kg. • Excellent long-term stability with 83.52% capacitance retention after 4000 cycles. [ABSTRACT FROM AUTHOR]

Developing low-cost electrode materials with high performance for supercapacitor still faces great challenges. In this work, CoTe 2 nanoflowers (NFs) were successfully developed by employing a facile solvothermal route. The transmission electron microscopy image reveals that the thickness of the CoTe 2 is approximately 20 nm, which will improve the contact area with electrolyte as well as boost the ions/chargers transport rate. Results from the electrochemical measurement disclose that the CoTe 2 NFs electrode has an outstanding electrochemical capacitance of 460 F g−1 under 1.5 A g−1. Specifically, the 91% of electrochemical capacitance is retained after 5000 cycles, demonstrating its good cycle durability. Our results reveal that the CoTe 2 NFs is kind of promising electrode material for use in the advanced energy storage system. [ABSTRACT FROM AUTHOR]

The development of efficient and stable non-precious metal-based bifunctional catalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is central for water splitting in the practical application. In this paper, the flower-like Ni 0.7 Co 0.3 P architecture consisted of self-assembled nanosheets with numerous holes was fabricated by a facile hydrothermal–phosphorization method. The nanoflowers with open architecture and rippled nanosheets with numerous holes can enlarge the efficient reaction interface area and facilitate the mass transport, boosting the efficiency for water splitting. The obtained Ni 0.7 Co 0.3 P electrocatalyst exhibits outstanding electrocatalytic performances for both OER and HER in alkaline media with low overpotentials of 230 and 105 mV at 10 mA cm−2, as well as small Tafel slopes of 78 and 58 mV dec−1, respectively. Moreover, the resultant catalyst demonstrates excellent durability, maintaining a steady overpotential at 10 mA cm−2 after testing for 25 h toward both OER and HER. The exceptional electrocatalytic properties of Ni 0.7 Co 0.3 P nanoflowers can be explained by the following two points: (i) the exposure of abundant electroactive sites in the 3D flower-like architectures assembly by nanosheets with numerous defective holes, and (ii) the promoted kinetics of OER and HER achieved by the partial Co substitution and moderate electron delocalization. Unique flower-like Ni 0.7 Co 0.3 P architecture consisted of self-assembled nanosheets with numerous holes exhibits exceptional electrocatalytic performances toward both OER and HER. Unlabelled Image • Hydrothermal–phosphorization method was used to synthesize Ni 0.7 Co 0.3 P nanoflowers. • Ni 0.7 Co 0.3 P nanoflowers consisted of self-assembled nanosheets with numerous holes. • Ni 0.7 Co 0.3 P nanoflowers need overpotential of 230 mV to deliver 10 mA cm−2 for OER. • The Ni 0.7 Co 0.3 P nanoflowers exhibit a low HER overpotential of 105 mV at 10 mA cm−2. • The moderate electron delocalization provided by P boosts the reaction kinetics. [ABSTRACT FROM AUTHOR]

SnO 2 quantum dots interspersed Bi 2 WO 6 nanoflowers were successfully synthesized to create a cost-efficient electrode material specifically designed for energy storage devices. The performance of the electrodes was evaluated by studying their structural and functional properties. The SnO 2 quantum dots coupled with Bi 2 WO 6 nanoflowers-based electrodes exhibited an enhanced electrochemical behavior compared to those without the SnO 2. A functional investigation of the developed electrodes in a 3 M KOH electrolyte demonstrated specific capacitance values of 812 and 741 F.g−1 (225.5 and 206 mAh.g−1) for SnO 2 -Bi 2 WO 6 (BWSq) and Bi 2 WO 6 (BW) nanoflowers, respectively, at a current density of 7 A.g−1. Excellent cycling stability was observed for both BWSq and BW electrodes, with specific capacity values of 226 and 159 mAh.g−1 (814 and 572 F.g−1), respectively, after 3000 cycles at a current density of 22 A.g−1. The fabricated BWSq symmetric super-capacitor (SSC) device demonstrated a superior performance with an exceptional specific capacitance of 75.6 F.g−1 when subjected to a current density of 0.5 A.g−1. Additionally, the device displayed impressive energy and power densities, reaching 31.1 Wh.kg−1 and 14040 W.kg−1, respectively. Moreover, the BWSq SSC device demonstrated notable cyclic stability, manifesting a capacity retention of 62% over 5000 galvanostatic charge-discharge cycles. The outcomes of this study suggest that the BWSq nanostructure holds immense promise as a prospective contender for energy storage applications, offering great potential for practical implementation. • A novel SnO 2 quantum dots interspersed Bi 2 WO 6 nanoflowers (BWSq) electrode material prepared for supercapacitor. • BWSq demonstrates superior specific capacitance, rate capability, and cycling stability compared to Bi 2 WO 6 nanoflowers (BW). • Fabrication and evaluation of a high-performance symmetric supercapacitor (SSC) using BWSq electrodes. • Enhanced charge transfer behavior in BWSq electrodes, highlighting their potential for advanced energy storage applications. [ABSTRACT FROM AUTHOR]

• Magnetic fluid hyperthermia (MFH) of nanoflowers based dispersion and it's in vitro study is reported. • The nanoclusters were characterized using XRD, TEM, DLS, VSM and MFH before investigating it with the breast cancer cells. • The effect of MFH, before and after the treatment of induction heating on MDA-MB-231 cells, were also studied. • Results show that MFH is capable to kill almost 87% cells within 30 min of treatment on cells with magnetic nanoclusters. • This shows a potential of developed nanoflowers for the treatment of cancer over other magnetic nanoparticles. Magnetic fluid hyperthermia (MFH) is emerging as an alternate treatment therapy for cancer of different types, due to its potential low side effects and relatively less painless treatment option. However, the implementation of standalone therapy is still challenging and needs research to optimize the effective killing of 100% cancerous tissues, number of therapy sessions, time duration of the therapy, controlled hyperthermia window temperature, etc. We report here the potential of nanoclusters (nanoflowers) based dispersion and on an in vitro study on breast cancer cells (MDA-MB-231). The nanoclusters were characterized using XRD, TEM, DLS, VSM and MFH, before investigating them with breast cancer cells. The effect of MFH, before and after the treatment of induction heating on MDA-MB-231 cells, were also studied. Results show that the MFH is capable of killing almost 87% of cells within 30 min of treatment on cells in the presence of magnetic nanoclusters. This shows the potential of developing nanoflowers for the treatment of cancer over other single domain magnetic nanoparticles. [ABSTRACT FROM AUTHOR]

• ZnO has been synthesised into three different nanoforms, nanogranules, nanowires, nanoflowers. • Partial specificity towards H 2 S, NO and the mixture is achieved. • Incorporation of Pt is responsible for the change in the morphology from nanowires to nanogranules. • Regression analysis indicates that a wise selection of combination of sensors gives better prediction accuracy. Understanding the intricate relationship among the gas sensing data produced from different ZnO morphologies is crucial for optimizing electronic nose (e-nose) performance. In the present work, three different morphologies of ZnO namely nanoflowers (NFs), nanogranules (NGs) and nanowires (NWs) have been successfully synthesised and used for e-nose application. Incorporation of Pt in the reaction mixture has been found to be responsible for change in the morphology from NWs to NGs. The partial specificity of the developed sensors towards H 2 S, NO and their mixture has been used effectively for discrimination of gases. For this, the data repository was created utilizing labelled data as well as feature data. Elaborate study on principal component analysis shows well discrimination of target gas mixture. Importantly, using support vector machine it has been demonstrated that a wise selection of combination of sensors can give a very good accuracy on the prediction of target gas mixture. [ABSTRACT FROM AUTHOR]

3-dimensional (3D) nanostructures have gained broad attention in the field of microelectronics and nanotechnology owing to their fascinating properties and potential for novel applications. To enable successful fabrication of the nanostructure, deep understanding on their growth mechanism is an absolute prerequisite. In this study, thin film of hematite (α-Fe 2 O 3) nanoflakes is successfully converted to nanoflowers using aerosol-assisted chemical vapour deposition (AACVD) technique simply by supplying high amount of oxygen and regulating the deposition time. The crystal structure and morphological properties including thickness and roughness of the film are thoroughly investigated to provide a clear explanation on the growth mechanism of α-Fe 2 O 3 by AACVD. Results indicate that (110) crystal plane is the predominant factor that influence the formation of nanoflowers with unique pyramidal nanostructure. This structure causes the film thickness to increase linearly while the surface roughness shows a logarithmic growth trend. The samples are further employed in photoelectrochemical (PEC) water splitting as photoanode where 40 min deposition period is the optimum condition for achieving PEC photocurrent density of up to 585 μA/cm2 at 1.2 V vs. Ag/AgCl. The major contributor towards the performance enhancement is the large surface area and high light absorption of α-Fe 2 O 3 nanoflowers as this parameter provides greater sites for photocatalytic activity, greater charge generation and enhanced charge carrier separation efficiency. [ABSTRACT FROM AUTHOR]

Morphology and phase have significant role in the performance of catalysts. Herein, we fabricated various novel and highly hierarchical flower-like copper sulfide superstructures of CuS and Cu 1.8 S phase through self-assembly of nanoplates or nanosheets via solvothermal reaction by adjusting the ratio of precursors and the type of solvent (i.e. 2-propanol, methanol, and mixed 2-propanol: water). Subsequently, the growth mechanism of superstructures was systematically investigated. These results demonstrate that the copper sulfide superstructures display surface area, morphology, and phase-dependent catalytic activity for decolorization of organic dye in an aqueous medium. Additionally, the rose like CuS structures showed the highest rate constant and reusability property. Thus they could be useful for environmental pollution cleanup as an efficient catalyst. [ABSTRACT FROM AUTHOR]

The current industrial revolution signifies the high-value of biocatalysis engineering. Over the past decade, multiple micro- and nanostructured materials have been attempted for immobilization of enzymes to improve their catalytic properties. Conventional immobilization strategies result in improved stability, while insolubilized enzymes generally lost their activity compared to free counterparts. Recently, a new generation organic-inorganic hybrid nanoflowers with unique properties have received great attention as a novel and incentive immobilization approach owing to their simple fabrication, high biocatalytic efficiency, and enzyme stabilizing capability. The hybrid nanoflowers biocatalytic system implicates metal ions and biomolecules (enzymes). In contrast to free or conventionally immobilized enzymes, single enzyme or multi enzyme-incorporated flowers-like hybrid nanoconstructs demonstrated elevated catalytic activities and stabilities over a very broader range of experimental conditions, i.e., pHs, temperatures and salt concentration. This review discusses the recent developments in the fabrication strategies to diversifying nanoflowers, types, characteristics, and applications of organic-inorganic hybrid nanoflowers as a host platform to engineer different kinds of enzymes with requisite functionalities for biocatalysis applications in different sectors of the modern world. Based on experimental and theoretical literature data, the review is wrapped up with concluding remarks and an outlook in terms of upcoming challenges and prospects for their scale-up applications. [ABSTRACT FROM AUTHOR]

• We have synthesized flower and rods-like ZnO nanostructures by a hydrothermal method. • Gas sensing properties of synthesized ZnO nanostructures strongly depend on their morphology and size. • The hierarchical leaf-like nanoflowers show excellent gas sensing properties. • The ZnO sensors shows highest response towards NO 2 at ppb level. Here, we report the hydrothermal synthesis of flower-shaped ZnO nanostructures and investigated their morphology-dependent gas sensing properties. Scanning electron microscope (SEM) study confirmed the formation of two kinds of floral structures. At short reaction time, flower-like structures (2–3 μm in size) composed of nanoparticles are formed, whereas floral assemblies (˜ 5 μm) of nanorods are formed at long reaction time. X-ray diffraction (XRD) confirmed the formation of the hexagonal wurtzite structure of ZnO. The average crystallite size of prepared nanoflowers and nanorods were found to be 21 nm and 43 nm, respectively. These results are supported by transmission electron microscopy (TEM). The band gap of ZnO nanostructures was calculated from the UV–vis absorption spectrum and found to be 3.0 eV and 3.19 eV for ZnO nanoflowers and nanorods, respectively. Broad absorption peak in the visible region of photoluminescence (PL) spectra confirmed the presence of oxygen vacancies in both specimens. Furthermore, morphology dependent gas sensing property was investigated for ethanol, benzene, carbon monoxide, and nitrogen dioxide at different operating temperatures and concentrations. Although both morphologies have shown good sensitivity and selectivity towards NO 2 at ppb, the response of nanoflower was higher than that of nanorods, which was attributed to its relatively higher surface area and amount of surface defects. [ABSTRACT FROM AUTHOR]

To significantly improve the electrochemical performance of ReS 2 , fluffy carbon-coated ReS 2 nanoflowers (named as ReS 2 /C nanoflowers) are prepared with assistance of the polyethyleneglycol (PEG) as carbon source and surfactant. The carbon-coating structure of ReS 2 /C nanoflowers derived from PEG can improve the conductivity of the composites and relief the volume expansion of ReS 2 during the cycling process. Furthermore, the fluffy structure and small size of ReS 2 /C nanoflowers controlled by PEG are propitious to the transmission of Li ion. Thus, the obtained ReS 2 /C nanoflowers exhibited a superior electrochemical performance compared with the pure ReS 2 , which exhibit a discharge capacity of 501 mAh g-1 at 0.5 C as anode materials for LIB after 100 cycles, with a high capacity retention of 98%. This preparation of ReS 2 /C nanoflowers can provide guidance for improving the electrochemical performances of ReS 2 for Li storage. Image 109 • Fluffy ReS 2 /C nanoflowers are successfully prepared. • The PEG is used as carbon source and surfactant. • The ReS 2 /C nanoflowers own fluffy structure and smaller size due to the effect of PEG. • The ReS 2 /C nanoflowers exhibit superior Li storage compared with pure ReS 2. [ABSTRACT FROM AUTHOR]

Abstract Three dimensional (3D) flower-like BiOCl nanostructures were synthesized by a facile and mild solution chemistry method at room temperature without any post-treatment. It is found that the volume ratios of ethylene glycol to water (EG-W) play an important role in the nucleation and growth of BiOCl, which consequently determine the self-assembly and thus the morphology of BiOCl nanostructures. In the solution of high EG-W ratio, the thin nanosheets self-assemble into 3D flower-like nanostructures, resulting in large surface area and abundant oxygen vacancies. The oxygen vacancies facilitate the trapping and transfer of photogenerated electrons to adsorbed oxygen molecules, producing active O 2 ·− species. As a result, the BiOCl nanoflowers exhibit much higher photocatalytic activity for RhB degradation under visible light irradiation than their nanosheets counterparts synthesized in the solution of low EG-W ratios. Graphical abstract Unlabelled Image Highlights • 3D flower-like BiOCl were synthesized via a facile solution chemistry method. • The ratios of EG-W in synthesis affect the morphology and activity of BiOCl. • Flower-like BiOCl exhibits superior visible-light-driven photocatalytic activity. [ABSTRACT FROM AUTHOR]

Graphical abstract BiOI nanosheets/chrysanthemum-like nanoflowers were deposited on the surface of TiO 2 nanotube arrays by a SILAR method. The visible light photocurrent density of TiO 2 NTs/BiOI prepared with 7 SILAR deposition cycles was 120.06 μA/cm2 and the photovoltage was −203.61 mV/cm2. The TiO 2 NTs/TiO 2 NTs/BiOI samples showed the optimal photoelectrocatalytic removal efficiencies of methyl orange, rhodamine B, methyl blue and Cr(VI). Highlights • Chrysanthemum-like BiOI nanoflowers were deposited on TiO 2 NTs by a SILAR method. • The TiO 2 NTs/BiOI photoelectrode showed the excellent photoelectrochemical properties. • The p-n heterojunction PEC mechanism of TiO 2 NTs/BiOI photocatalysts was proposed. Abstract The BiOI nanosheets/chrysanthemum-like nanoflowers were successfully deposited on the surface of TiO 2 nanotube arrays (TiO 2 NTs) by the successive ionic layer adsorption and reaction (SILAR) method, and the morphology and visible light response of samples with different SILAR deposition cycles were investigated in detail. The as-prepared BiOI/TiO 2 NTs significantly enhanced photoelectrocatalytic (PEC) activity for the removal of Methyl orange (MO), Rhodamine B (RhB), Methylene blue (MB) and Cr(VI). The as-prepared Sample-7 with chrysanthemum-like nanostructures showed the high visible light photocurrent density of 120.06 μA/cm2, photovoltage of −203.61 mV/cm2, PEC efficiencies of 45%, 62%, 79% and 77% for the removal of MO, RhB, MB and Cr(VI), respectively. The high PEC performances could be ascribed to the excellent visible light response and charge carrier transportation in chrysanthemum-like BiOI nanoflowers. By further probing the charge separation and transportation behaviors, the experiments of the energy band structure and active species trapping were carried out. A possible p-n heterojunction photocatalytic mechanism was proposed, which not only benefited the efficient separation of photogenerated electrons but also demonstrated the advanced capacity for the PEC removal of organic dyes and heavy metal ions. [ABSTRACT FROM AUTHOR]

Abstract Electrochemical supercapacitors are vital for the advancement of energy storage devices. Herein, we report the synthesis of molybdenum selenide (MoSe 2), tungsten-doped molybdenum selenide (W MoSe 2) and their graphene (G) composites (W MoSe 2 /G) via a facile hydrothermal method. Physiochemical properties of the as-synthesized samples are examined using X-ray diffraction, Raman spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller measurements, scanning electron microscopy, high resolution transmission electron microscopy and energy dispersive X-ray spectroscopy measurements. Used as working electrodes for supercapacitors, MoSe 2 nanostructures could deliver the specific capacitance of 106 F g−1 at 2 mV s−1 scan rate. Further, doping with tungsten (W) demonstrates the variation of specific capacitances with 2 M % of tungsten as the optimum doping amount, delivering the maximum specific capacitance of 147 F g−1. Furthermore, graphene composites of these nanostructures deliver the enhanced specific capacitances of 248 F g−1 and complimented with excellent capacitance retention capability of 102% for 20000 cycles. Graphical abstract Image 1 Highlights • Molybdenum selenides (MoSe 2) were prepared employing hydrothermal method. • Tungsten (W) doping enhanced the specific capacitances of electrodes. • Specific capacitance depends on W-doping concentration. • Graphene composites display enhanced specific capacitance and cyclic retention. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • [Zn 6 (IDC) 4 (OH) 2 (Hprz) 2 ] n MOFs have been synthesized and characterized as a new adsorbent. • The effects of ultrasonic irradiation parameters on morphology of this MOF were investigated. • Fast and effective removal of antibiotics in aqueous media by [Zn 6 (IDC) 4 (OH) 2 (Hprz) 2 ] n MOFs with good recyclability. • Antibiotics adsorption was related with BET surface area and pore volume of MOF. • Adsorption isotherms, kinetics and affinity were comprehensively investigated. Abstract In this study, various sonochemical conditions were applied to prepare the microsheets, nanosheets and nanoflowers of a metal-organic framework (MOF; [Zn 6 (IDC) 4 (OH) 2 (Hprz) 2 ] n) that is composed of Zn(II) cations coordinated with the linear N-donor piperazine (prz) and rigid planar imidazole-4,5-dicarboxylate (H 3 IDC) ligands. The PXRD patterns approved purity of the samples and the FT-IR spectra related the detected bonds and functional groups to [Zn 6 (IDC) 4 (OH) 2 (Hprz) 2 ] n crystals. The morphological results indicated that any changes in the synthesis conditions can affect nucleation and morphology of the nanostructures. The prepared MOF nanosheets and nanoflowers (with particle size average of 95 and 116 nm, respectively) were employed to adsorb the ampicillin, amoxicillin and cloxacillin antibiotics. Then, the MOFs were calcined at 550 ℃ and atmospheric pressure to produce ZnO nanoparticles and the resultant nanoparticles were adopted to photodegrade the antibiotics. These nanoparticles can photodegrade 37% of the amoxicillin compounds within 180 min. Among the examined samples, the nanoflowers demonstrated the highest adsorption capacity by eliminating 92.5%, 88% and 89% of the antibiotic molecules from the 60-ppm amoxicillin, ampicillin and cloxacillin solutions, respectively. Also, these nanoflowers are thermally stable up to 365 ℃. The associated adsorption process was found to follow pseudo-first-order kinetics, in the case of amoxicillin. [ABSTRACT FROM AUTHOR]

Abstract Bisphenol A (BPA) has been identified as one of the endocrine disrupting chemicals. However, the issue that BPA widely exists in various environments has puzzled people for decades. To develop highly efficient, easy separation, recyclable and reusable materials for BPA degradation in water, laccase-loaded magnetic nanoflowers (MNFs) were prepared by attaching amino-functionalized magnetic nanoparticles onto the laccase-inorganic hybrid nanoflowers. Characterization results showed that MNFs were spherical, porous and hierarchical structure with an average diameter of 15 μm to which magnetic nanoparticles was successfully attached through electrostatic force. MNFs exhibited excellent catalytic activity on BPA degradation under room temperature in the presence of ABTS. Under optimized conditions, MNFs reached 100% BPA degradation for only 5 min. In addition, it still retained over 92% of its initial activity after 60 days of storage at 4 °C, indicating that its thermal and storage stabilities have been improved. When the MNFs was recycled and reused 5 cycles, only 5% decrease in degradation efficiency of BPA was observed. These results suggest that MNFs possess great efficiency and reusability in the treatment of aqueous solution containing BPA and is a novel promising material. Graphical abstract Unlabelled Image Highlights • Laccase-loaded magnetic nanoflowers (MNFs) were successfully prepared. • The thermal stability and storage stability of MNFs were enhanced. • Under optimized conditions, MNFs reached 100% BPA degradation within only 5 min. • Degradation efficiency of MNFs for BPA decreased only 5% after reused 5 cycles. • MNFs were easily separated from reaction solution by an external magnetic field. [ABSTRACT FROM AUTHOR]

Abstract Mechanically-induced self-sustaining reactions (MSRs) in WO 3 B 2 O 3 Mg C powder mixtures were investigated in terms of reductant content. Also, two different predictive intelligent-based techniques including Adaptive Neuro-Fuzzy Inference System (ANFIS) and Multi-Layer Perceptron Artificial Neural Network (MLP-ANN) were developed to estimate the structural features of the mechanosynthesized powders, where different statistical analysis were performed to prove the precision and robustness of proposed models. The phase compositions were changed as the concentration of ductile reductant (Mg) reduced in the system. Accordingly, the fraction of crystalline phases was dramatically altered after the leaching process. The structural assessment showed that the dislocation density significantly varied as the graphite content increased, however, the rate of these alterations was not linear. FESEM observations indicated that the leached product had a typical flower-like cluster configuration, which consisted of loosely organized nano-sheets with a side length and thickness of around 250 and 12 nm, respectively. Meanwhile, the results achieved from the intelligent-based techniques showed that both ANFIS and ANN are very powerful in estimating the structural characteristics of the mechanosynthesized powders. However, ANFIS was more accurate than MLP-ANN. Graphical abstract Image 1 Highlights • Mechanically-induced self-sustaining reactions in WO 3 B 2 O 3 Mg C system were studied. • High-purity nanocomposites were obtained after 1 h of milling and subsequent leaching. • A bimodal particle size distribution was observed. • Flower-like cluster structure consisted of loosely arranged nano-sheets. • Two different modeling methodologies were developed to predict the structural features. [ABSTRACT FROM AUTHOR]

Abstract Nanoflowers are highly beneficial structural features for improving catalysis on transitional metal-based materials with regarded to the electrocatalytic activity, cost effectiveness and durability. In this study, the manganese dioxide nanoflowers onto sulfonated graphene sheets (denoted as δ-MnO 2 /SGS) is synthesized by a simple hydrothermal method for bifunctional electrocatalytic application in oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER). The formation of δ-MnO 2 nanoflowers onto SGS plays a crucial role in intrinsic catalytic activity, resulting in an impressive enhancement in both ORR and HER in alkaline electrolyte. The morphological features and X-ray analysis are shown the successful sulfonation and the Mn presents in oxide form with δ-type crystallographic structure. The growth reaction mechanism of δ-MnO 2 nanoflowers is proposed in alkaline media. The robust electrocatalysis is inherited from the cave among crystalline lego-block-like petals at microscale level and the large interlayer spacing at nanoscale level of δ-MnO 2 nanoflowers with significant electrical conductivity. The δ-MnO 2 /SGS catalyst exhibits nearly same ORR and HER activity in terms of current density with electron transfer and final current density with Tafel slope, respectively, compare to the benchmark Pt/C. [ABSTRACT FROM AUTHOR]

Abstract In the present work, nanostructures comprising of plasmonic silver (Ag) nanoparticles (NPs) decorated on the hydrothermally grown bismuth sulfide nanorods (Bi 2 S 3 –NR) and hierarchical nanoflowers (Bi 2 S 3 NF) have been successfully synthesized by chemical route. We have fabricated the nanostructured photoanodes and demonstrated their enhanced photoelectrochemical (PEC) performance for water splitting applications. Bismuth sulfide nanoflowers have shown appreciable increased PEC activity due to its hierarchical structure as compared to the nanorods facilitated by the faster charge transport due to the availability of more interfacial sites. Among all, Ag/Bi 2 S 3 NF photoanode has exhibited highest photocurrent density (12.34 mA/cm2 at 2 V vs. Ag/AgCl) which is ∼2 fold higher as compared to Bi 2 S 3 nanoflowers. A ∼3 fold enhancement in the incident photon-to-current conversion efficiency is achieved by Ag/Bi 2 S 3 NF photoanode as compared to Bi 2 S 3 NF photoanode. The remarkable enhancement in the photocurrent density of Bi 2 S 3 after grafting metal plasmons is attributed to its enhanced photoresponse, faster transfer of plasmon mediated hot electrons from excited state of Ag NPs to Bi 2 S 3 surface and higher separation efficiency of photogenerated charge carriers facilitated by the metal-semiconductor interface. A plausible mechanism is also proposed for the improved PEC water splitting over Ag/Bi 2 S 3 NF photoanode. Graphical abstract Plasmonic silver (Ag) NPs have been successfully grafted on the hydrothermally grown bismuth sulfide nanorods (Bi 2 S 3 –NR) and hierarchical nanoflowers (Bi 2 S 3 NF) via chemical method. The Ag NPs coupled Bi 2 S 3 photoanode (Ag/Bi 2 S 3 NF) has demonstrated ∼2 and ∼3 fold enhancement in the photocurrent density and incident photon-to-current conversion efficiency (IPCE), respectively as compared to Bi 2 S 3 NF photoanode. The observed enhancement in the PEC activity for Ag/Bi 2 S 3 NF photoanode is attributed to the faster transport of plasmon mediated hot electrons from excited state of Ag NPs to the conduction band of Bi 2 S 3 nanoflowers and the slower recombination rate of photogenerated charge carriers facilitated by the metal-semiconductor interface. Image 1 Highlights • Bi 2 S 3 has been synthesized in the form of nanorods and hierarchical nanoflowers by hydrothermal method. • Plasmonic Ag NPs have been grafted on the Bi 2 S 3 nanostructures by chemical route. • A ∼2 and ∼3 fold enhancement in the photocurrent density and IPCE is achieved by Ag/Bi 2 S 3 NF as compared to Bi 2 S 3 photoanode. • The improvement is due to the enhanced photoresponse and surface plasmonic effect. [ABSTRACT FROM AUTHOR]

Abstract ZnO nanoflower like structure is synthesized by low cost wet chemical method. The growth of flower like morphology is controlled by optimizing the annealing temperature. Structural, vibrational and morphological characterizations are carried out through X-ray diffraction, FTIR, Raman, SEM and TEM analysis respectively. Crystal structure and physical parameters are analyzed and estimated through Williamson Hall energy density models. Further, second harmonic generation of ZnO nanoflowers confirms the existence of non-centrosymmetric nature of the sample. Moreover, the ferroelectricity of the synthesized ZnO nanoflowers is identified by the polarization hysteresis behavior. Typical 80 Hz mechanical detection of the synthesized samples manifests the response of its vibration sensing nature. Therefore, it is established that the synthesized ZnO nanoflowers will be a suitable candidate for the fabrication of sensors like pressure or vibration for industrial applications. Highlights • ZnO nanoflowers is synthesized and its growth is controlled by temperature. • Ferroelectric nature of was explained by the structural defects. • 80 Hz mechanical detection manifests the response of its vibration sensing nature. • Maximum sensitivity of 116 mV/g is achieved. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Hexagonal ZnO nanoflowers/reduced graphene oxide nanocomposite preparation via simple chemical decomposition method. • The synthesized nanocomposite exhibited a high specific capacitance of 203 F g−1. • The nanocomposite showed ∼98% electrochemical stability for 10,000 cycles. Abstract We demonstrated a facile and scalable synthesis of crystalline hexagonal ZnO nanoflowers/reduced graphene oxide nanocomposite (ZnO-NFs/RGO NCs) via direct chemical decomposition of zinc hexacyanoferrate (ZnHCF) over reduced graphene oxide (RGO) nanosheets. The phase formation and degree of functionalization of as-synthesized ZnO-NFs/RGO NCs was confirmed from XRD and FT-IR spectroscopic analysis, respectively. The hierarchical ZnO nanoflowers consist of 2D nanosheets wrapped with RGO nanosheets was confirmed from FE-SEM and HR-TEM images. The synthesized ZnO-NFs/RGO NCs exhibits a high specific capacitance of 203 F g−1 at the current density of 1 A g−1 with good rate performance and also showed an excellent electrochemical stability of 98% for 10,000 cycles at high current density of 20 A g−1. [ABSTRACT FROM AUTHOR]

Abstract Ferrimagnetic iron oxide nanoparticles (magnetite or maghemite) have been the subject of an intense research, not only for fundamental research but also for their potentiality in a widespread number of practical applications. Most of these studies were focused on nanoparticles with spherical morphology but recently there is an emerging interest on anisometric nanoparticles. This review is focused on the synthesis routes for the production of uniform anisometric magnetite/maghemite nanoparticles with different morphologies like cubes, rods, disks, flowers and many others, such as hollow spheres, worms, stars or tetrapods. We critically analyzed those procedures, detected the key parameters governing the production of these nanoparticles with particular emphasis in the role of the ligands in the final nanoparticle morphology. The main structural and magnetic features as well as the nanotoxicity as a function of the nanoparticle morphology are also described. Finally, the impact of each morphology on the different biomedical applications (hyperthermia, magnetic resonance imaging and drug delivery) are analysed in detail. We would like to dedicate this work to Professor Carlos J. Serna, Instituto de Ciencia de Materiales de Madrid, ICMM/CSIC, for his outstanding contribution in the field of monodispersed colloids and iron oxide nanoparticles. We would like to express our gratitude for all these years of support and inspiration on the occasion of his retirement. Graphical abstract This review summarizes the colloidal synthetic routes leading to magnetic iron oxide nanoparticles with different morphologies and analyses the key parameters on each route that govern particle size and shape. Structural and magnetic properties for each morphology are also reviewed and related to the synthetic route as well as the advantages of using magnetic anisometric nanoparticles in biomedical applications and others. Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract The present work demonstrates the morphology dependent synthesis of manganese oxide using simple hydrothermal method just by adjusting the reaction temperature. The structural and morphological studies confirm the formation of manganese oxide with different phases and anisotropic structures of manganese oxide. Interestingly, electrochemical studies exhibit significant oxygen reduction reaction (ORR) kinetics by manganese oxide nanowires with improved onset potential of +0.83 V versus reversible hydrogen electrode (RHE) and current density of 1.75 mA/cm2 in alkaline condition. Among three different morphologies, nanowires show better catalytic activity due to improved diffusion path length and higher aspect ratio. However, all the three samples follow two (2) - electron transfer ORR kinetics, though four electron transfer kinetics has been of great interest for energy conversion applications. Experimental results represent that the reaction temperature plays a key role in forming different shapes and affect the crystal phase and growth process thereby affecting electrochemical properties. Highlights • Different morphologies are obtained in a simple and cost effective one-step hydrothermal method just by adjusting reaction temperature. • The structural analysis confirms that the nanowires as well as nanoflowers consist of mixed phases of Mn 2 O 3 and Mn 3 O 4 , whereas nanoparticle comprise single phase of Mn 3 O 4. • Comparative electrochemical study shows that the manganese oxide nanowires exhibit better ORR activity. [ABSTRACT FROM AUTHOR]

Graphical abstract Bismuth sulfide (Bi 2 S 3) has been synthesized in the morphology of hierarchical nanostructures by facile hydrothermal method. The photocatalytic efficiency of Bi 2 S 3 nanostructures has been checked for the degradation of MB, RhB single dye solution and their binary mixture and compared with commercial TiO 2 (Degussa P25) sample under visible light illumination. The degradation rate of RhB and MB is enhanced by ∼8 times and ∼3 times in their binary solution as compared to that in single dye solution and increased by ∼14 times than that of Degussa P25 for both RhB and MB degradation in the binary solution, respectively. This remarkable improvement in the photocatalytic activity of Bi 2 S 3 is attributed to the faster separation of charge carriers at the interface due to the favourable LUMO and HOMO alignment of RhB and MB with band levels of Bi 2 S 3 in the RhB-MB-Bi 2 S 3 trio system. The photocatalytic degradation study of colourless contaminants, p-chlorophenol (CP), p-nitrophenol (NP) and their mixture (CP-NP) is also investigated. The degradation rate of NP is observed to be highest in the single solution, whereas, the degradation rate of both CP and NP is found to decrease in binary mixture solution in comparison to their individual solution. Highlights • Hierarchical nanostructures of Bi 2 S 3 have been synthesized by hydrothermal method. • Utilized Bi 2 S 3 for the photodegradation of MB, RhB and their binary solution. • Demonstrated the enhanced photocatalytic activity in RhB-MB-Bi 2 S 3 trio system. • Degradation of p-chlorophenol (CP), p-nitrophenol (NP) and CP-NP over Bi 2 S 3. • Achieved highest degradation rate of NP among all phenolic compounds. Abstract Hierarchical nanostructures of bismuth sulfide (Bi 2 S 3) have been synthesized by a facile hydrothermal method. The potentiality of Bi 2 S 3 hierarchical nanostructures for the photocatalytic degradation of Rhodamine B (RhB), Methylene blue (MB) and the mixture of RhB-MB organic dyes have been demonstrated and compared with commercial TiO 2 (Degussa P25) sample under visible light illumination. The degradation efficiency of Bi 2 S 3 and Degussa P25 is found to be higher in the single as well as in the binary dye solution for MB degradation as compared to RhB degradation. Furthermore, the degradation rate of RhB and MB is enhanced by ∼8 times and ∼3 times in their binary solution as compared to that in single dye solution. Whereas, Bi 2 S 3 has demonstrated ∼14 times higher degradation rate of both RhB and MB in their binary solution than that of Degussa P25 for RhB and MB degradation in the binary solution under visible light exposure, respectively. Interestingly, Bi 2 S 3 nanostructures has exhibited larger improvement in the degradation efficiency for RhB in its binary solution which is attributed to the faster separation of photogenerated charge carriers due to the proper alignments between the molecular orbits of dyes and band level positions of Bi 2 S 3 in RhB-MB-Bi 2 S 3 heterogenous system. The photocatalytic degradation study of colourless contaminants, p-chlorophenol (CP), p-nitrophenol (NP) and their mixture (CP-NP) is also investigated in the presence of Bi 2 S 3 nanoflowers. Among the phenolic compounds, the degradation rate of NP is observed to be highest in the single solution. However, the degradation rate of both CP and NP is found to decrease in binary mixture solution in comparison to their individual solution. A possible mechanism for the enhanced photodegradation of RhB-MB dye mixture based on the active species trapping experiment has been proposed. [ABSTRACT FROM AUTHOR]

Graphical abstract Irreversible solid-state conversion of [Pb(1,4-BDC)(C 2 H 5 OH)(C 2 H 5 OH)] n (1) nanoflowers, which also recognized as MOF-70, prepared by mechanochemical solid–solid and solid–gas processes, to nonporous coordination polymer of [Pb(1,4-BDC)] n (2) with agglomerated nanoparticle morphology has been observed upon thermal treatment of MOF-70 at 100 °C. This conversion is one of the rare solid-state structural conversions of nanoporous MOF to nonporous coordination polymer. Abstract The reaction between 1,4-benzenedicarboxylic acid and Pb(NO 3) 2 in the presence of hydrogen peroxide and triethylamine with mechanochemical solid–solid and solid–gas processes results in formation of [Pb(1,4-BDC)(C 2 H 5 OH)(C 2 H 5 OH)] n (1) nanoflowers. This compound also recognized as MOF-70. The MOF-70 porosity did not maintain by heating up to 100 °C and converted to nonporous coordination polymer of [Pb(1,4-BDC)] n (2) with agglomerated nanoparticle morphology. Thus the pore destruction in 1 during removal of coordinated EtOH molecules and formation of 2 with higher thermal stability than 1 are two driving force during this irreversible conversion. [ABSTRACT FROM AUTHOR]

Flower-shaped Pt-Pd nanostructures supported on carbon (Pt-Pd/C) were successfully synthesized by simple wet-chemical processing by controlling the rate of reduction of a dissolved metal precursor. L-ascorbic acid (AA) was employed as a green and clean reductive agent for the coreduction of [PtCl 6 ] 2− and [PdCl 4 ] 2− in an aqueous solution. The electrocatalytic activity of nanoporous Pt-Pd/C on the oxygen reduction reaction (ORR) was investigated by rotating disk electrode voltammetry in a 0.1 M HClO 4 solution. In particular, the Pt 77 -Pd 23 /C catalyst showed surpassing ORR activity and acceptable stability under acidic conditions compared to the commercial Pt electrocatalyst. The outstanding electrocatalytic activity was achieved by a combination of the high surface area of flower-like nanostructures and the bimetallic synergetic effect. The morphology, composition and structure of the Pt-Pd/C nanoflowers were confirmed by scanning transmission electron microscopy (STEM), TEM, X-ray photoelectron spectroscopy and X-ray diffraction. Overall, the Pt-Pd/C bimetallic nanostructures are expected to become promising cathode material in fuel cells to replace monometallic Pt ones. [ABSTRACT FROM AUTHOR]