Copper Hexacyanoferrate Nanoparticles Research Articles

Flexible supercapacitors based on carbon fiber cloth coated copper hexacyanoferrate nanoparticles as positive electrode material

Herein, we report fabrication of a new electrode material based on copper(II) hexacyanoferrate(II) nanoparticles coated on flexible and light weight carbon fiber cloth (CuHCF-NPs@CC) for supercapacitors application. Uniform spherical CuHCF-NPs are successfully synthesized through a simple chemical co-precipitation technique at ambient temperature. The CuHCF-NPs were physically examined by different characterizations, for example, FT-IR, UV–Visible, Raman, XRD, XPS, FE-SEM, EDAX and TEM. The CuHCF-NPs@CC is an excellent electrode material that has an open framework structure that can accommodate a wide variety of ions. The electrochemical characteristics of pseudocapacitive behavior of the material were characterized by cyclic voltammogram (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) on two different electrolytes such as K2SO4 and Na2SO4. The CuHCF-NPs@CC exhibits a good reversible cycle in the range of 0 to 0.9 V and excellent charge-discharge performance with a specific capacity of 42.96C g−1 and 24.2C g−1 at 0.2 A g−1 of current density in K2SO4 and Na2SO4 electrolyte, respectively. The low cost, simple preparation methodology, and an outstanding electrochemical behavior of CuHCF-NPs@CC considering a viable candidate for the future energy storage system.

Enzyme-Regulated In Situ Formation of Copper Hexacyanoferrate Nanoparticles with Oxidase-Mimetic Behaviour for Colorimetric Detection of Ascorbate Oxidase.

In this study, a copper hexacyanoferrate nanoparticle with excellent oxidase-mimetic behaviour has been synthesized through a simple precipitation method. The synthesized copper hexacyanoferrate nanoparticle has intrinsic oxidase-like activity, which can catalyze the chromogenic reaction of 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) through an O2•- reactive oxygen-species-participated process. On the other hand, K3[Fe(CN)6] can be reduced by ascorbic acid (AA) to produce K4[Fe(CN)6], thereby inhibiting the formation of the copper hexacyanoferrate nanoparticles. Furthermore, ascorbate oxidase (AAO) can catalyze the oxidation of AA to produce dehydroascorbic acid, which cannot reduce K3[Fe(CN)6]. Thus, a system for an AAO-regulated in situ formation of copper hexacyanoferrate nanoparticles was constructed by coupling a prepared copper hexacyanoferrate nanozyme with AA for the detection of AAO activity. This colorimetric sensing assay shows high sensitivity and selectivity for the detection of AAO activity (the limit of detection is 0.52 U/L) with a linear range of 1.1-35.7 U/L. Finally, the developed method was applied to detect the activity of AAO in normal human serum with a satisfactory sample spiked recovery (87.4-108.8%). In short, this study provides a good strategy for the construction of nanozyme-based multi-enzyme cascade-signal amplification assay.

Enzyme-controllable just-in-time production system of copper hexacyanoferrate nanoparticles with oxidase-mimicking activity for highly sensitive colorimetric immunoassay

Nanozymes are a series of elaborately designed nanomaterials that can mimic the catalytic sites of natural enzymes for reactions. Bypassing the tedious design and preparation of nanomaterial, in this work, we report on a novel just-in-time production system of copper hexacyanoferrate nanoparticles (CHNPs), which act as an oxidase-mimicking nanozyme. This system can rapidly produce CHNPs nanozyme on demand by simply mixing Cu(II) with potassium hexacyanoferrate(III) (K3[Fe(CN)6]). It is found that once K3[Fe(CN)6] is reduced to K4[Fe(CN)6], the formation of CHNPs is inhibited. Therefore, the just-in-time production system of CHNPs was coupled with alkaline phosphatase (ALP) to construct an enzyme-controllable just-in-time production (ECJP) system, in which ALP could inhibit the production of by catalyzing the hydrolysis of ascorbic acid 2-phosphate (AAP) to generating ascorbic acid (AA). The ECJP system is then used to probe the activity of ALP by employing 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) as the chromogenic substrate, and a detection limit of 0.003 U L−1 was achieved. Moreover, by adapting ALP as the enzyme label, an ECJP system-based colorimetric immunoassay protocol was established for sensitive detection of aflatoxin B1 (AFB1), and a detection limit as low as 0.73 pg mL−1 was achieved. The developed immunoassay method is successfully applied to the detection of AFB1 in peanut samples. The operation of ECJP system is quite simple and the coupling of ALP with CHNPs nanozyme can arouse dual enzyme-like cascade signal amplification. So, we believe this work can offer a new perspective for the development of nanozymes-based biodetection methods and colorimetric immunoassay strategies.

Enzyme-Controllable Just-in-Time Production System of Copper Hexacyanoferrate Nanoparticles with Oxidase-Mimicking Activity for Highly Sensitive Colorimetric Immunoassay

Enzyme-Controllable Just-in-Time Production System of Copper Hexacyanoferrate Nanoparticles with Oxidase-Mimicking Activity for Highly Sensitive Colorimetric Immunoassay

Polydopamine-coated magnetic montmorillonite immobilized with potassium copper hexacyanoferrate for selective removal of Cs+ and its facile recovery

To address the challenges in remediating cesium contaminated aqueous environments, a low-cost, magnetically recoverable and superior composite adsorbent was fabricated based on the concept of magnetizing montmorillonite and entrapping potassium copper hexacyanoferrate that offers excellent selectivity for Cs+. The facile, green and scalable synthesis route involved exchanging the interlayer ions of montmorillonite with ferrous ions before oxidizing to form magnetic montmorillonite using a low-temperature hydrothermal method. The composite was then coated with polydopamine to be complexed with copper ions and subsequently reacted with the hexacyanoferrate precursor to in situ grow potassium copper hexacyanoferrate nanoparticles, thus forming the composite, D-Mt-Mag-HCF. The adsorbent exhibited excellent Cs+ sorption capacity (~159.2 mg/g) and Cs+ selectivity greater than 8.2 × 104 mL g−1 in concentrated brine. Moreover, the magnetic properties (17.4 emu/g) of the adsorbent facilitated its separation from contaminated aqueous environments once the adsorbent had removed Cs+. The current study demonstrates a novel and scalable production of a composite adsorbent that can be readily used to remediate contaminated water.

Scattering techniques to probe the templating effect in the synthesis of copper hexacyanoferrate nanoparticles via reverse microemulsions

The formation of nanoparticles (NPs) by means of reverse microemulsions results in generally homogeneous shapes with fairly narrow size distributions. We report here a study of the behaviour of the microemulsion (NaAOT/Isooctane/water) during the formation of copper hexacyanoferrate NPs inside water nanodroplets (CuPBA for Prussian Blue Analogous). Small angle X-ray and neutron scattering (SAXS, SANS) provide additional information on the size, shape and interaction between the micelles. SAXS shows that as soon as CuPBA NPs are present in the system, long-range interactions occur between the micelles, even for the smallest amount of NPs. On the other hand, the SANS matching technique allows to consider only the diffusion of the NPs by deactivating the diffusion of the rest of the system. The size of the NPs found with SANS is in agreement with TEM observations for intermediate contents of aqueous phase in the microemulsion (5.1 ± 0.9 nm for w = 10). Finally, FTIR and XRD confirm the formation of CuPBA networks. Moreover, TEM shows that the size of the NPs is in agreement with the radius of the nanodroplets given by SAXS, except for a higher water content where the system is closer to destabilisation, thus producing larger NPs with a wide size distribution (13.6 ± 4.6 nm for w = 20) compared to the droplet radius.

Nanocrystals FAU-X monoliths as highly efficient microreactors for cesium capture in continuous flow

Abstract The performances of binderless FAU-X monoliths (0.5 × 3 cm) build of nanocrystals featuring hierarchical trimodal porosity (micro-/meso-/macroporosity) in decontamination Cs-containing effluents have been evaluated. They have been compared to those obtained with newly synthesized FAU-X particles (1 mm) build with nanocrystals. Data have been confronted to those recently reported for a benchmark reference Cs+ adsorbent Sorbmatech®, based on copper hexacyanoferrate nanoparticles (15 nm) immobilized into mesoporous silica particles (250–500 μm) (Cu-HCF@SiO2). FAU-X monoliths show high rate of adsorption in batch in less than 2 min, much faster than Cs+ adsorption in FAU-X particles (60 min). This result highlights the importance of a homogeneous macropore network in adsorbents to enhance mass transport and access to the zeolite active sites. FAU-X monoliths with 20 μm macropore diameter have been used in continuous flow experiments for sequestering Cs+ (0.5 mmol/L) in mineral drinking water containing competing cations (Ca2+, Mg2+, Na+, K+) with flow rates of 0.5–1 mL/min, corresponding to Darcy rates of 1.5–3 m/h. FAU-X monoliths are very efficient for Cs+ removal and show ideal steep breakthrough curves characteristic of fast diffusion. FAU-X monoliths are as excellent as Cu-HCF@SiO2 and could represent an alternative adsorbent for safer processes, avoiding the handling of powders or particles. Above all, this study reveals the unique hydrodynamic behavior of FAU-X monoliths and opens the route for process intensification using FAU-X in continuous flow.

Carbon nanotubes functionalized with copper hexacyanoferrate nanoparticles for a selective extraction of cesium from liquid waste

Single-walled carbon nanotubes are functionalized with copper hexacyanoferrate nanoparticles for the liquid-solid extraction of cesium from liquid waste and contaminated water. The functionalization process is followed mainly by x-ray photoemission spectroscopy. Indeed, determining the chemical environment around carbon or nitrogen atoms allows to evidence the formation of covalent bounding. In addition, the signatures of iron and copper ions give information on the effective growth of hexacyanoferrate nanoparticles. Furthermore, the cesium sorption mechanism is investigated by comparing the peak intensities associated to the response of potassium and cesium ions. Finally, based on the liquid chromatography analyzes, the sorption of cesium with the functionalized carbon supports is studied. The main results of this work are the demonstration of both a good selectivity of cesium trapping and a high sorption capacity by hybrid single-walled carbon nanotubes.

Highly Sensitive Determination of Hydrazine Using Copper Hexacyanoferrate Nanoparticles Modified on Commercial Junction Field-Effect Transistor as Ion Sensitive Field-Effect Transistor

In this paper, for the first time, we introduce a simple and low cost hydrazine sensor based on a commercial junction field-effect transistor (JFET). The transistor was mechanically treated, isolated, and used as an ion sensitive FET (ISFET) for hydrazine detection, after the electrodeposition of the sensing membrane on its metal gate surface. Copper hexacyanoferrate nanoparticles as suitable sensing membrane were electrodeposited on the copper metal gate of transistor from a solution containing K4Fe(CN)6 by a cyclic voltammetry method. The prepared sensor showed a super-Nernstian response of 94.8 mV pHyd−1 over a linear concentration range of $1.17\times 10^{-5}$ – $2.15\times 10^{-2}$ M, a very low drift of 0.04 mV h−1, and the detection limit of $3.16~\mu \text{M}$ . Also, the various ISFET characteristics of the prepared sensor were studied and discussed.

Synthesis of poly(diallyldimethylammonium) capped copper hexacyanoferrate (CuHCF) nanoparticles: An efficient stabiliser for Pickering emulsions

Poly(diallyldimethylammonium chloride) (PDDA) capped copper hexacyanoferrate nanoparticles (CuHCF NPs) with the controlled size are prepared following a precipitation method. While PDDA and CuHCF are not active at the cyclohexane/water interface, PDDA capped CuHCF NPs present synergistic property permitting them to stabilise oil-in-water emulsions for weeks. These latter can be considered as promising precursors for the development of new porous materials considering the fact that the NPs present some interests in the field of nuclear decontamination.

Facile immobilization of potassium-copper hexacyanoferrate nanoparticles using a room-temperature ionic liquid as an ionic binder and its application towards BHA determination

In this paper, a facile immobilization of copper hexacyanoferrate nanoparticles (CuHCFNP) on a paraffin wax-impregnated graphite electrode (PIGE) was carried out using the room-temperature ionic liquid (RTIL) 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4) as an ionic binder. The characteristics of the CuHCFNP/EMIMBF4 gel-modified electrode were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques, and the modified electrode morphology was also characterized using field emission scanning electron microscopy (FESEM). The electrocatalytic behavior of butylated hydroxyl anisole (BHA) at the modified electrode has been investigated in 0.1 M KNO3 in static and dynamic conditions. Under the optimum conditions, the oxidation peak current was proportional to the BHA concentration in the range from 1.5 to 1000 μM with a detection limit of 0.5 μM (S/N = 3). The proposed method was applied to determine BHA content in real samples with satisfactory results.

Copper hexacyanoferrate nanoparticles as cathode material for aqueous Al-ion batteries

Copper hexacyanoferrate (CuHCF) nanoparticles with Prussian blue structure present the ability to insert Al ions reversibly in aqueous solution.

An Original “Click and Bind” Approach for Immobilizing Copper Hexacyanoferrate Nanoparticles on Mesoporous Silica

We present an original approach for preparing silica-based nanocomposites containing Prussian blue-type nanoparticles via click chemistry. Click reaction is used to prepare a triazole-copper complex in a single step; this complex is subsequently used to anchor copper hexacyanoferrate nanoparticles within a porous silica matrix (porous glass pearls or SBA-15). This CuAAC “click reaction” was performed using a relatively large copper concentration for two reasons: First, the Cu catalyzes the triazole ring formation, then the ring acts as a chelator, immobilizing the copper inside the silica matrix. Successively adding hexacyanoferrate precursors that coordinate with the copper ions at the triazole sites led to efficient and selective nanocomposite formation; this material was developed to mitigate Cs+ ion contamination. The efficiency of these as-prepared nanocomposites and their selectivity for Cs+ from different effluents, such as pure water, seawater, and radioactive seawater (simulating the Fukushima site), were evaluated using sorption experiments. These immobilized nanocomposites present a high Cs+ selectivity while demonstrating a Kd value above that of the bulk material.

Preparation of a film of copper hexacyanoferrate nanoparticles for electrochemical removal of cesium from radioactive wastewater

We first synthesized water-dispersed nanoparticle copper hexacyanoferrate (CuHCF) ink and then coated its nanoparticles on electrodes to electrochemically remove cesium from wastewater. Cesium uptake and elution can be controlled by switching the potentials between anodes and cathodes. Effective cesium removal can be adopted in a large pH range from 0.2 to 8.9, and in the presence of several diverse coexisting alkaline cations, suggesting that it can be taken as a promising technology for actual radioactive wastewater treatment. The prepared CuHCF nanoparticles can be simply and uniformly coated on electrodes by wet process like conventional printing methods, so any sizes or patterns are feasible at low cost, which indicated the potential as a promising sorption electrode of large size in the columns for sequential removal and recycle of Cs from wastewater.

Synthesis of Water-Dispersible Copper Hexacyanoferrate Nanoparticles and Electrochromism of the Thin Films

A Prussian blue analog (PBA), copper hexacyanoferrate (Cu-PBA) has been synthesized as an insoluble aggregated solid of nanoparticles (NPs). The Cu-PBA NPs bore negative surface-charge via their surface modification using [FeII(CN)6]4− and were stably dispersed into water from the insoluble solid. Spin-coated thin films consisting of the Cu-PBA NPs on ITO glass substrates showed reversible electrochromism of red (reduced form) and yellow (oxidized form). The spectroscopic investigation revealed that the reduced form of Cu-PBA was a mixed valence form included Cu(I).

Electrochemical preparation of copper hexacyanoferrate nanoparticles under the synergic action of EDTA and HAuCl 4

A convenient method for electrochemical deposition of compact and uniform CuHCF nanoparticles was proposed. The size and the deposition rate of CuHCF nanoparticles could be easily controlled with the synergic action of EDTA and HAuCl 4 in the deposition solution. The possible mechanism was investigated by using electrochemical and SEM techniques. Moreover, electrodeposition conditions such as pH, concentrations of HAuCl 4 and EDTA as well as the initial concentration of ferricyanide had also been optimized. The resulting modified electrode exhibited excellent catalytic activity and improved stability for the oxidation of hydrazine. Hydrodynamic amperometry was applied for the determination of hydrazine with a linear range of 5.0 × 10 −7–2.0 × 10 −3 mol L −1 and the sensitivity was 194.0 μA mM −1.

Copper hexacyanoferrate nanoparticles modified electrodes: A versatile tool for biosensors

Copper hexacyanoferrate nanoparticles of about 30 nm in size have been prepared by the sonochemical irradiation of a mixture of aqueous potassium ferricyanide and copper chloride solutions. The nanoparticles were immobilized onto fluorine doped tin oxide (FTO) electrodes by using the electrostatic deposition layer-by-layer technique (LbL), obtaining electroactive films with electrocatalytic properties towards H 2O 2 reduction, providing higher currents than those observed for electrodeposited bulk material, even in electrolytes containing NH 4 + , Na + and K +. The nanoparticles assembly was used as mediator in a glucose biosensor by immobilizing glucose oxidase enzyme by both, cross-linking and LbL techniques. Sensitivities obtained were dependent on the immobilization method ranging from 1.23 μA mmol −1 L cm −2 for crosslinking to 0.47 μA mmol −1 L cm −2 for LbL; these values being of the same order than those obtained with electrodes where the amount of enzyme used is much higher. Moreover, the linear concentration range where the biosensors can operate was 10 times higher for electrodes prepared with the LbL immobilization method than with the conventional crosslinking one.

Synthesis and Characterization of Copper Hexacyanoferrate Nanoparticles for Building Up Long-Term Stability Electrochromic Electrodes

Nanoparticles of a Prussian blue (PB) analogue, copper hexacyanoferrate, were synthesized by using ultrasonic radiation and characterized by spectroscopic and electrochemical techniques. The nanoparticles (ca. 10 nm diameter) were immobilized onto transparent indium tin oxide electrodes by electrostatic layer-by-layer deposition. These modified electrodes showed interesting electrochromic properties, changing the coloration during the redox process from brown to orange when oxidized. The nanostructured electrode presented high stability, in contrast to that observed for PB nanoparticles; this fact must be related to the maintenance of the electrostatic assembly because the oxidized compound, CuII/FeIII(CN)6, still possesses a negative excess of charge due to the high number of cyanide groups that link the nanoparticles with the polycation, assuring the integrity of the whole electrostatic assembled film.