One-pot Co-precipitation Research Articles

The magnetic and photocatalytic properties of nanocomposites SrFe12O19/ZnFe2O4

Magnetic composites SrFe12O19/ZnFe2O4 were successfully synthesized by one-pot coprecipitation method. The as-prepared samples with different molar ratio of SrFe12O19 to ZnFe2O4 were characterized and analysed. XRD and SEM results show that the composites are highly crystalline with few impurities. Raman spectrum confirms the interactions between two phases in the composites. UV–vis spectra and photoluminescence spectra show the optical property of the samples. The magnetic properties analysis reveals that the coercivity of composites decrease evidently with the increase of the ZnFe2O4 phase. Furthermore, photocatalytic performance of the samples were investigated by the degradation of methylene blue (MB) under visible light irradiation. The maximum degradation ratio of MB with Sample-A was 90%. The recycling tests confirm that the photocatalytic activity was above 50% after three cycles. These all prove that the composite SrFe12O19 and ZnFe2O4 not only improve the magnetic and photocatalytic properties, but also effectively avoid secondary pollution of treated water.

High-performance Li1.2Mn0.6Ni0.2O2 cathode materials prepared through a facile one-pot co-precipitation process for lithium ion batteries

In a quest to produce cathode materials for lithium ion batteries that yield high capacities, the Li1.2Mn0.6Ni0.2O2, lithium-manganese rich cathode materials were synthesized via a facile one-pot co-precipitation process with various ratios of urea at pH 9.0, 9.5, 10.0 and 10.5. The physical properties of the cathode materials were analysed by X-ray diffraction, Brunauer–Emmett–Teller surface area, scanning electron microscopy, transmission electron microscopy, inductively coupled plasma mass spectrometry and energy dispersive spectroscopy. The X-ray diffraction study showed that the prepared materials were crystalline with an ordered layered structure in the respective unit cell parameters being indexed to a monoclinic C2/c space group. Scanning electron microscopy showed that Li1.2Mn0.6Ni0.2O2 particles are agglomerated, however pH 10.0 particles appear less agglomerated and possess a slightly higher surface area. The cathode materials were built into coin cells and displayed exceptional electrochemical performance in delivering more than 200 mAh g−1 at a constant current density of 20 mA g−1 in the voltage range of 2.0 V–4.8 V. In particular the cathode material made at pH 10.0 delivered an initial high discharge capacity of 266 mAh g−1 at 20 mA g−1 current density and maintained a discharge capacity of more than 220 mAh g−1 at 50 mA g−1 after 50 cycles.

Mesoporous spinel manganese zinc ferrite for high-performance supercapacitors

We report on the synthesis of manganese zinc ferrite (MnZnFe2O4) nanoneedles via a simple one-pot coprecipitation method and their characterization using energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), high-resolution transmission electron microscope (HR-TEM) and N2 adsorption/desorption techniques. The electrochemical performance of MnZnFe2O4 nanoneedles-based supercapacitors was investigated, showing superior specific capacitance of 783 F g−1, which is significantly higher than that reported for any ferrite material. Also, the spinel MnZnFe2O4 exhibits very high columbic efficiency and an excellent long-term stability. The fabricated asymmetric supercapacitor based on MnZnF2O4 nanoneedles/activated carbon electrodes can deliver 15.8 Wh kg−1 energy density at a power density of 899.7 W kg−1. The contribution of the double layer capacitance was found to be only 3.14% of the total specific capacitance and mainly based on psuedocapacitance faradaic mechanism. Therefore, the fabricated MnZnFe2O4 electrode is a promising candidate for supercapacitor applications.

A Mechanistic Approach for the Synthesis of Carboxylate-Rich Carbonaceous Biomass-Doped Lanthanum-Oxalate Nanocomplex for Arsenate Adsorption

Considering the protocol of “zero-alkaline waste disposal” for green and arsenic-free environment, lanthanum (La3+)-based MOF-like complex materials were designed, and the complex materials have been employed as adsorbent for AsO43– adsorption from water. The sucrose-derived porous carbon (SPC)@La-oxalate complex was prepared by a simple one-pot coprecipitation method at room temperature, where oxalate has been used as an organic ligand, and the carbonaceous biomass has been used as a doping material that is naturally a carboxylate-rich functional group derived from a sucrose biomass. In addition to SPC@La-oxalate, bare-SPC, La(OH)3, and SPC@La(OH)3 were also prepared via simple base-addition conventional methods, and their performances in AsO43– removal were compared. The FTIR peak at 848 cm–1 confirmed the presence of AsO43– on the SPC@La-oxalate complex after adsorption of 1 mM AsO43–. The high resolution X-ray photoelectron spectrum for the AsO43– adsorbed SPC@La-oxalate showed a peak at EB[As 3d] = 4...

Small-Sized Mg-Al LDH Nanosheets Supported on Silica Aerogel with Large Pore Channels: Textural Properties and Basic Catalytic Performance after Activation.

Layered double hydroxides (LDHs) have been widely used as an important subset of solid base catalysts. However, developing low-cost, small-sized LDH nanoparticles with enhanced surface catalytic sites remains a challenge. In this work, silica aerogel (SA)-supported, small-sized Mg–Al LDH nanosheets were successfully prepared by one-pot coprecipitation of Mg and Al ions in an alkaline suspension of crushed silica aerogel. The supported LDH nanosheets were uniformly dispersed in the SA substrate with the smallest average radial diameter of 19.2 nm and the thinnest average thickness of 3.2 nm, both dimensions being significantly less than those of the vast majority of LDH nanoparticles reported. The SA/LDH composites also showed large pore volume (up to 1.3 cm3·g) and pore diameter (>9 nm), and therefore allow efficient access of reactants to the edge catalytic sites of LDH nanosheets. In a base-catalyzed Henry reaction of benzaldehyde with nitromethane, the SA/LDH catalysts showed high reactant conversions and favorable stability in 6 successive cycles of reactions. The low cost of the SA carrier and LDH precursors, easy preparation method, and excellent catalytic properties make these SA/LDH composites a competitive example of solid-base catalysts.

Polyacrylic acid-coated iron oxide magnetic nanoparticles: The polymer molecular weight influence

Magnetic nanoparticles (MNPs), in particular, magnetic iron oxide-based nanoparticles were found to be useful as catalysts and as devices for data storage, environmental remediation and several biomedical applications, due to their excellent properties, such as biocompatibility and high magnetic moment. Polyacrylic acid (PAA) is a weak polyelectrolyte that can be used to stabilize the MNPs. To the best of our knowledge, the influence of PAA molecular weight and PAA concentration over the magnetic and structural properties of iron oxide nanoparticles has not been previously reported. The aim of this paper is to describe the differences evidenced in the properties of different magnetic materials by using PAA for iron oxides stabilization by one-pot coprecipitation synthesis. Iron oxide-based magnetic nanoparticles stabilized by polyacrylic acid (PAA) polymers were efficiently prepared and exhaustively characterized. The influence on the employment of two different low PAA molecular weights, Mw 1800 g/mol and 5000 g/mol, in three different iron salts: PAA ratios was analyzed. In summary, the main results showed that: for a certain PAA reactor feed higher oligomer quantities are present in MNPs as higher is the involved molecular weight of the polymeric chain; when molecular weight raises the contribution of loops and tails also does it, allowing having higher polymer contents. For both PAA’s Mw employed as the adsorbed PAA increases particles hydrodynamic diameters decreases, and their distribution becomes narrower; the PAA adsorbs onto iron oxides by chemisorption (the most probable interaction is the bidentate bridging). For the studied cases z potential values depend much more on the PAA’s quantity adsorbed onto the iron oxides than on the PAA’s Mw. MNPs are superparamagnetic and choosing the right shape of particle distribution is not central for getting estimates of the magnetization saturation, the average particle diameter and its standard deviation, while better fits are found with Normal and Log-Normal particle size distributions.

Multifunctional mixed valence N-doped CNT@MFe2O4 hybrid nanomaterials: from engineered one-pot coprecipitation to application in energy storage paper supercapacitors.

This work reports on the design of novel mixed valence hybrid N-doped carbon nanotubes/metal ferrite nanomaterials (MFe2O4, M(ii) = Mn, Fe, Co) with tailored composition, and magnetic and electrical properties through a straightforward eco-sustainable and less time consuming one-pot in situ coprecipitation process. The potentialities of this strategy rely on the lack of oxidative treatments to the support and thermal annealing, besides the use of aqueous conditions, a chelating base (isopropanolamine) and low temperatures. The process afforded the controlled nucleation/growth of the MFe2O4 nanoparticles (NPs), with sizes of 3.2-5.4 nm and superparamagnetic properties, on the surface of the N-doped carbon nanotubes (CNT-N) and their immobilization by covalent bonding. The nitrogen-based functionalities of CNT-N allied with the use of a coprecipitation agent with coordinating properties towards M(ii)/Fe(iii) cations were responsible for these achievements. To unravel the potentialities of the novel nanohybrids (CNT-N@M), they were tested as electrode active nanomaterials in the fabrication of all-solid-state asymmetric paper supercapacitors (SCs). All asymmetric SCs presented significantly higher performance than the symmetric CNT-N based one, with an enhancement of the energy density to up to 6.0× and of the power density to up to 4.3× due to the occurrence of both non-faradaic and faradaic charge storage mechanisms. Moreover, they led to enhanced volumetric energy density (up to 11.1×) and power density (up to 5.2×) compared with other solid-state hybrid paper SCs based on carbon materials recently reported in the literature. These results highlight the importance of conjugating a conductive support bearing N-based functionalities with MFe2O4 NPs featuring redox properties towards synergistically enhanced energy storage.

An efficient synthetic strategy for uniform perovskite core–shell nanocubes NaMgF3:Mn2+,Yb3+@NaMgF3:Yb3+ with enhanced near infrared upconversion luminescence

Uniform perovskite core–shell nanocubes NaMn1−xMgxF3@NaMgF3 and NaMn1−xMgxF3:Yb3+@NaMgF3:Yb3+ have been successfully synthesized via a facile one-pot co-precipitation method at room temperature.

Photocatalytic CO2 reduction promoted by uniform perovskite hydroxide CoSn(OH)6 nanocubes

Herein, we report the facile synthesis of uniform perovskite hydroxide CoSn(OH)6 nanocubes and their first use as noble-metal-free, highly efficient and stable catalysts for the deoxygenative reduction of CO2 to CO with visible light. The CoSn(OH)6 sample is synthesized through a one-pot co-precipitation method and fully characterized by various techniques including XRD, FTIR, FESEM, TEM, EDX, EDX-mappings, XPS, DRS, and N2 sorption measurements. The CoSn(OH)6 solid is found by theoretical calculations to be capable of absorbing and activating CO2 molecules on the (100) surface. Under the optimal reaction conditions, the CoSn(OH)6 catalyst exhibits a high CO2 reduction activity with visible light irradiation, affording a CO generation rate of 18.7μmolh−1. The stability and reusability of the CoSn(OH)6 catalyst for photocatalytic CO2 reduction are solidly confirmed. Results of in situ photoluminescence spectroscopy and photocurrent response characterizations indicate that the CoSn(OH)6 catalyst can efficiently promote the separation and transfers of photoexcited charge carriers during photocatalysis, and eventually leading to obviously enhanced CO2 photoreduction performance. Moreover, a possible mechanism for the photocatalytic CO2 reduction reaction is also proposed based on the results of activity evaluation and photo-/electro-chemical measurements.

Temperature responsive fluorescent polymer nanoparticles (TRFNPs) for cellular imaging and controlled releasing of drug to living cells

Recent studies have demonstrated that drug delivery by using functional nanomaterials with imaging capability could afford plenty of insightful information for the better control of the delivery process. In this work, we developed temperature responsive fluorescent nanoparticles (TRFNPs) for drug delivery and cellular imaging. The TRFNP was fabricated by one-pot co-precipitation of thermal sensitive amphiphilic block copolymers polystyrene-b-poly(N-isopropyl acrylamide) (PS-b-PNIPAM) and fluorescent conjugated polymer poly [(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(1,4-benzo(2,1′,3)-thiadiazole)] (PFBT) in the presence of desired small guest molecules. The dynamic light scattering (DLS) measurements verified that this functional nanoparticle exhibited temperature dependent size variation, which could therefore regulate the releasing rate of loaded guest molecules (e.g. drugs) inside the polymer core. Besides, the TRFNPs displayed good photostability in terms of optical characterization. The cellular cytotoxicity characterization demonstrated that this nanoparticle exhibited good biocompatibility even under the mass concentration of 10μg/mL. By using Nile Red as a model molecule, the temperature-controlled releasing process from TRFNPs in solution as well as inside living cells was monitored directly according to the spectroscopic and microscopic characterizations. Furthermore, anti-cancer drug was successfully delivered into living cells via TRFNPs and released in a temperature dependent manner. As a consequence, owing the attractive merits as mentioned above, this nanostructure would find broad applications in nanomedicine in the future.

Silver ferrite/maghemite composites and mixtures: Impact of one-pot composite preparation on battery-relevant electrochemistry

A series of silver ferrite/maghemite composite materials (AgxFeOy, where AgxFeOy=composites of xAgFeO2+[(1−x)/2] γ-Fe2O3 and y=2−(1−x)/2) have been prepared via a non-stoichiometric, one-pot co-precipitation strategy. The impact of a one-pot composite preparation on electrochemistry was determined by comparison to a mechanical mixture of nanocrystalline AgFeO2 and γ-Fe2O3 powders, which were combined to afford an overall composition of Ag0.2FeO1.6. Notably, following 30 discharge-charge cycles, the one-pot Ag0.2FeO1.6 composite delivers an energy density (156mWh/g) profoundly higher than the mechanical mixture Ag0.2FeO1.6 (67mWh/g). AgxFeOy composites with the lowest Ag (x) content and smallest crystallite size, Ag0.2FeO1.6, deliver twice the discharge energy density (169mWh/g) of stoichiometric AgFeO2 with no maghemite component and exhibited good capacity retention over 50 cycles. The notable electrochemistry of one-pot AgxFeOy composites may involve reduced AgFeO2 and γ-Fe2O3 aggregate sizes and a concomitant increase in AgFeO2/γ-Fe2O3 crystallite contact not achievable through mechanical mixing.

One-pot synthesis of dextran-coated iron oxide nanoclusters for real-time regional lymph node mapping.

The intraoperative precision cleaning of lymph nodes (LNs) is an essential component of treating neoplastic disease. To develop efficient probes for the targeted detection of LNs that could act as carriers for the specific diagnosis and treatment of metastatic LNs in the future, dextran-coated iron oxide nanoclusters (DIONs) were synthesized using a one-pot coprecipitation procedure. These modified DIONs have good water dispersibility, cytocompatibility, an optimum size, and a stable, dark brown color for LN imaging. In this study, cytotoxicity was evaluated using lymphatic endothelial cells (LECs) to predict biosafety and biocompatibility. Most importantly, the effectiveness of DIONs in mapping perigastric LNs in Sprague Dawley rats following injection into the gastric submucosal layer was demonstrated. In addition, a long-term tracing in vivo (from 4 days to 3 months) indicated that the DIONs had good biosafety and biocompatibility according to an evaluation of the behavior and blood biochemistry of the rat and a histopathological examination of the important organs.

Biocompatible magnetite nanoparticles synthesized by one-pot reaction with a cell membrane mimetic copolymer

In this paper, a series of random copolymers poly(methacrylic acid -co-2-methacryloyloxyethyl phosphorylcholine) P(MAA-co-MPC) were synthesized firstly via RAFT living polymerization. The P(MAA-co-MPC) copolymer side chains bear cell membrane phosphorylcholine zwitterions to endow biocompatibility and carboxylic groups to confer coordination with metal ions. Thus, the copolymer was adopted to modify Fe3O4 nanoparticle by a one-pot coprecipitation approach. The effects of the copolymer composition as well as the ratio between the copolymers and iron ions on the performances of the magnetite nanoparticles were researched. The diameters of the nanoparticles could be easily tuned by changing the initial copolymer amount. Moreover, a long-term colloidal stability of magnetite particles was obtained after P(MAA-co-MPC) modification. Biocompatibility of the P(MAA-co-MPC) copolymer coated magnetite nanoparticles was investigated by protein adsorption, in vitro cytotoxicity and cell uptake studies. It was found that the copolymer content of magnetite nanoparticles correlates with its biocompatibility. Excellent biocompatibility could be obtained when the content of the copolymer in the composite nanoparticles reached to 54%.

Hydrogen generation from decomposition of hydrous hydrazine over Ni-Ir/CeO2 catalyst

The synthesis of highly active and selective catalysts is the central issue in the development of hydrous hydrazine (N2H4·H2O) as a viable hydrogen carrier. Herein, we report the synthesis of bimetallic Ni-Ir nanocatalyts supported on CeO2 using a one-pot coprecipitation method. A combination of XRD, HRTEM and XPS analyses indicate that the Ni-Ir/CeO2 catalyst is composed of tiny Ni-Ir alloy nanoparticles with an average size of around 4nm and crystalline CeO2 matrix. The Ni-Ir/CeO2 catalyst exhibits high catalytic activity and excellent selectivity towards hydrogen generation from N2H4·H2O at mild temperatures. Furthermore, in contrast to previously reported Ni-Pt catalysts, the Ni-Ir/CeO2 catalyst shows an alleviated requirement on alkali promoter to achieve its optimal catalytic performance.

A novel synthesis of an Fe3+/Fe2+ layered double hydroxide ('green rust') via controlled electron transfer with a conducting polymer.

This report examines the influence of a conducting polymer on the crystal growth of labile green rust (GR) through hybridization with polypyrrole. All hybrids used in this study were prepared via one-pot co-precipitation at neutral pH, with specific stoichiometric ratios among all chemical species. The role of the conducting polymer and the effective stoichiometric ratio were demonstrated to facilitate the crystal growth of GR.

Nanostructured spinel manganese cobalt ferrite for high-performance supercapacitors

We report on the synthesis of manganese cobalt ferrite (MnCoFeO4) nanoparticles via a simple one-pot co-precipitation method and their characterization through energy-dispersive spectroscopy (EDS), XRD, HR-TEM, FT-IR and N2 adsorption/desorption techniques.

High rate performance Fe doped lithium zinc titanate anode material synthesized by one-pot co-precipitation for lithium ion battery

Fe doped lithium zinc titanate anode material has been synthesized via one-pot co-precipitation method for the first time. It is found that Fe element can enhance the electrochemical property of lithium zinc titanate obviously. Li2ZnFe0.05Ti2.95O8 particle shows largest specific capacity and best cyclic performance at high current densities among other particles. The introduction of Fe element improved electrochemical performance of the Li2ZnTi3O8 should be owing to the enhancement of the electric conductivity and lithium ion diffusivity of Li2ZnTi3O8.

Three-dimensional NiCo Layered Double Hydroxide Nanosheets Array on Carbon Cloth, Facile Preparation and Its Application in Highly Sensitive Enzymeless Glucose Detection

An ultrathin NiCo layered double hydroxide (LDH) nanosheet array was constructed on carbon cloth (CC) by one-pot co-precipitation approach. The NiCo LDH nanosheets possess high surface specific area and their interconnected three-dimensional (3D) structure allows easy access for electrolyte ions to process rapid and reversible faradic reactions. The as-prepared NiCo LDH/CC composites show a remarkable activity for glucose oxidation, which can be used as a binder-free biosensor for glucose detection. Under optimized conditions, the sensitivity can reach up to 5.12μAμM−1cm−2, the liner range covers four orders of magnitude from 1μM to 1.5mM, and the detection limit can be low as 0.12μM. Besides, this biosensor also shows superior selectivity, good stability, and easy reproducibility, holding promise as a good candidate for enzymeless glucose sensing.

Kinetics of catalytic decomposition of hydrous hydrazine over CeO2-supported bimetallic Ni–Pt nanocatalysts

Catalytic decomposition of hydrous hydrazine (N2H4·H2O) has been considered as one of the source of hydrogen for fuel cell applications, but the reaction kinetics has received very limited attention. The kinetics of the catalytic decomposition of alkaline N2H4·H2O solutions is investigated over bimetallic Ni–Pt nanocatalysts supported ceria (CeO2), which is prepared by a one-pot co-precipitation method. The resultant Ni–Pt/CeO2 catalyst exhibits high activity and 100% H2 selectivity for the N2H4·H2O decomposition. The catalytic decomposition of N2H4·H2O with respect to N2H4·H2O concentration follows a near-zero-order kinetics at the initial reaction stage with high N2H4·H2O concentrations and the fraction-order kinetics at low N2H4·H2O concentrations. The kinetic rate equation can be expressed as: r = – d[N2H4·H2O]/dt = k[N2H4·H2O]0.52/0.043[NaOH]0.57/0[catalyst]1.03, k = 4.64 × 108 exp(−6591.29/T). Our results provide valuable insights into the catalytic decomposition kinetics of N2H4·H2O.

Fabrication of hierarchical core-shell polydopamine@MgAl-LDHs composites for the efficient enrichment of radionuclides

Novel hierarchical core/shell structured polydopamine@MgAl-layered double hydroxides (PDA@MgAl-LDHs) composites involving MgAl-layered double hydroxide shells and PDA cores were fabricated thought one-pot coprecipitation assembly and methodically characterized by X-ray diffraction, Fourier transformed infrared spectroscopy, scanning/transmission electron microscopy, selected area electron diffraction, elemental mapping, thermogravimetric analysis and X-ray photoelectron spectroscopy technologies. U(VI) and Eu(III) sorption experiments showed that the PDA@MgAl-LDHs exhibited higher sorption ability with a maximum sorption capacity of 142.86 and 76.02mg/g at 298K and pH 4.5, respectively. More importantly, according to XPS analyses, U(VI) and Eu(III) were sorbed on PDA@MgAl-LDHs via oxygen-containing functional groups, and the chemical affinity of U(VI) by oxygen-containing functional groups is higher than that of Eu(III). These observations show great expectations in the enrichment of radionuclides from aquatic environments by PDA@MgAl-LDHs.