Prussian Blue Research Articles

Physicochemical Characterisation of Commercially Available Prussian Blue Insoluble Samples and Its Comparison with Radiogardase Cs

The physicochemical properties of insoluble Prussian blue (PB) play an important role in its thallium binding ability. Therefore, the present study aimed to characterise various physicochemical parameters of PB available commercially and compare them with the USFDA-approved Radiogardase ® -Cs. In addition, PB was synthesised by indirect and direct methods. PB samples and Radiogardase®-Cs were analysed for various parameters like particle size, moisture content, and thermogravimetric analysis (TGA) and correlated with its Maximum Binding Capacity (MBC) for thallium. Radiogardase ® -Cs showed the highest MBC of 238 mg/g for thallium with D 90 of 785 μm and moisture content of 23.24 %. The MBC of other PB samples was found to be significantly lower than Radiogardase ® -Cs which was found to be directly proportional to the moisture content. However, other parameters like particle size, and iron content vary significantly but no correlation was observed with MBC for thallium. This finding suggests that moisture content and MBC are extremely important parameters for optimising the PB to achieve desirable pharmacological efficacy for removing thallium in vivo.

Impedance spectroscopy and conduction mechanism analysis of bulk nanostructure Prussian blue pellets

The structure and morphology of the fabricated Prussian Blue (PB) pellets are examined using FTIR, XPS, XRD and FESEM techniques. The morphology of the crystalline Prussian blue (PB) revealed a nanostructure with an average crystallite size of 91 nm. The frequency (42 Hz–1 MHz) and temperature (303–393K) of the Prussian Blue (PB) in Bulk form are dependent. In the medium region (1 kHz–100 kHz), the electric dipoles relax and start to lag the applied ac electric field signal and the estimated activation energy of 0.247 eV. The investigated Nyquist plots (Z″ versus Z′) of the Prussian Blue (PB) samples at different temperatures (303–393 K) are interpreted by an equivalent parallel RgCg circuit. The bulk resistance of Prussian Blue samples was estimated at various temperatures, and its behaviour exhibited temperature dependence; generally, it follows the Nearest Neighbor Hopping (NNH) model. According to Meyer–Neldel rule, the calculated activation energy is 0.565 ± 0.001 eV. The evidence of localized states is investigated, and its density, N(EF) ∼ 5.47 × 1018 eV−1 cm−3. The ac conductivity, σac, merges into a plateau of two parts: the first is a frequency-independent dc conductivity, σdc, which is strongly temperature-dependent. The rest of the plateau at higher frequencies showed the temperature-insensitive ac conductivity obeying Jonscher's power law. The values of the exponent s were investigated to figure out the intimate conduction mechanism in Prussian Blue (PB) samples; it follows the correlated barrier hopping (CBH) theoretical model. The hopping distance and energy have values ∼ unity and ≥ kBT, respectively. The experimental results revealed a linear relationship between hopping distance and energy against temperature, with the first decreasing and the second increasing linearly.

Construction of Cu/ZIF-67/Prussian Blue Nanostructures with Photothermal-Enhanced Multizyme Activity for Cancer Therapy

Nanozymes that mimic the catalytic reaction of natural enzymes show great prospects for tumor catalytic therapy because they possess the properties of nanomaterials and natural enzymes. However, the therapeutic effect of nanozymes is restricted by the low catalytic efficiency and specific oxidation–reduction systems in the tumor microenvironment (TME), such as overexpressed glutathione (GSH) level. In order to improve the catalytic efficiency, a multifunctional nanozyme, Cu/zeolitic imidazolate framework-67 (ZIF-67)/Prussian blue (PB), was designed through the modification of Prussian blue (PB) on the surface of the copper-doped zeolitic imidazolate framework, which can be used for imaging-guided synergistic therapy with photothermal-enhanced multienzyme-like catalytic therapy and chemotherapy. The doping of Cu2+ provided better glutathione oxidase-like (GPx-like) activity and peroxidase-like (POD-like) activity to deplete GSH and increase the generation of •OH in TME. The modification of PB provided better catalase-like activity (CAT-like) to promote the production of O2 and enhance the multienzyme-like catalytic therapy. In vivo experiments showed a satisfactory anticancer effect. This work thus provided a strategy for designing a type of multifunctional nanozyme for imaging-guided combination therapy.

An electrochemical biosensor based on CuFe PBA/MoS2 nanocomposites for stable and sensitive detection of hydrogen peroxide and carcinoembryonic antigen

An increasing number of electrochemical biosensors have been constructed to detect single bioactive substances with high sensitivity, but not multiple bioactive substances with different properties. Therefore, we incorporated Cu and Fe elements into Prussian blue to form Prussian blue analogues (PBA) to improve the electrochemical catalytic activity of Prussian blue. At the same time, MoS2 is used as the material substrate to increase the electrochemical active site of the composite. We have constructed a universal electrochemical sensing platform using composite materials (CuFe PBA/MoS2) as electrode modification materials for detecting two different types of representative cancer biomarkers, hydrogen peroxide (H2O2) and carcinoembryonic antigen (CEA). The universal electrochemical biosensor showed a significant linear response to both H2O2 and CEA with the lowest detection limits of 0.23 μM and 0.01 ng mL−1, respectively, and it had high selectivity, reproducibility, and stability. The universal electrochemical biosensor is successfully applied to detect H2O2 released from human breast cancer (MCF-7) cells and CEA expressed on the surface of human cervical cancer (HeLa) cells. The developed biosensor has potential in the dynamic detection of the flux of H2O2 and the expression level of CEA from living cells. The high sensitivity of this universal sensor provides a novel strategy for simultaneously detecting multiple cancer biomarkers.

Casting and recycling of insoluble, labile single-crystal coordination polymer through reversible solid-liquid-solid transition

•Reversible solid-liquid-solid transition of insoluble, labile Prussian blue •Casting single-crystal Prussian blue with diverse shapes or compositions •All the cast Prussian blue can be recycled in a loop •Casting process leads to a significant improvement in the properties/performance Reversible solid-liquid-solid transition controlled by temperature or solvent plays a vital role in manufacturing and recycling many important materials. However, this kind of transition is hard to be realized for insoluble and labile materials, for instance coordination polymers. In this work, we introduce a volatile dissociating agent to realize reversible liquification and solidification of a kind of coordination polymer, Prussian blue. The Prussian blue powders are disassociated into electrolytic solution by hydrochloride acid (the volatile dissociating agent) and transformed back to solids via volatilization of the hydrochloride vapor. Using this solid-liquid-solid transition, Prussian blue powders are cast into single crystals with various shapes (i.e., inverse opal, mesoporous) or single-crystal matrix composites with functional networks encapsulated (i.e., carbon, silicon, TiO2). Significant improvements of the performance of Prussian blue in secondary battery, seawater battery, water treatment, etc., are observed after casting. Moreover, all of the cast Prussian blue materials can be recycled. Reversible solid-liquid-solid transition controlled by temperature or solvent plays a vital role in manufacturing and recycling many important materials. However, this kind of transition is hard to be realized for insoluble and labile materials, for instance coordination polymers. In this work, we introduce a volatile dissociating agent to realize reversible liquification and solidification of a kind of coordination polymer, Prussian blue. The Prussian blue powders are disassociated into electrolytic solution by hydrochloride acid (the volatile dissociating agent) and transformed back to solids via volatilization of the hydrochloride vapor. Using this solid-liquid-solid transition, Prussian blue powders are cast into single crystals with various shapes (i.e., inverse opal, mesoporous) or single-crystal matrix composites with functional networks encapsulated (i.e., carbon, silicon, TiO2). Significant improvements of the performance of Prussian blue in secondary battery, seawater battery, water treatment, etc., are observed after casting. Moreover, all of the cast Prussian blue materials can be recycled.

Microwave absorption properties of N-doped raspberry-like MWCNT/Fe2O3 composites based on Prussian blue

Microwave absorption properties of N-doped raspberry-like MWCNT/Fe2O3 composites based on Prussian blue

On the chemistry of the Archetti test for caffeine and uric acid

The Archetti colour test is based on the reduction of ferricyanide ions to ferrocyanide, giving Prussian blue. However, the oxidation sequence of reactions that take in the organic molecule has not been described. Some electroanalytical experiments on the oxidation of caffeine have been done but the results have not been adequately interpreted. Besides, they are incomplete since only the redox reactions can be detected, but not the isomerization and degradation path. In the present communication the complete oxidation route of caffeine is given, as well as the electron flow in each step. It involves hydration of the imino group and oxidation to 1,3,7-trimethyl-uric acid, formation of radical ion at C-9, interaction with the C─C double bond, aziridinone formation, carbon monoxide extrusion, carbonium ion neutralization, imine acidolysis, isomerization of carbinolamine and hydrolysis to the end products.

Prussian Blue nanoparticles: An FDA-approved substance that may quickly degrade at physiological pH

Prussian blue (PB) is a coordination polymer based on the Fe2+…CN…Fe3+ sequence. It is an FDA-approved drug, intended for oral use at the acidic pH of the stomach and of most of the intestine track. However, based on FDA approval, a huge number of papers proposed the use of PB nanoparticles (PBnp) under “physiological conditions”, meaning pH buffered at 7.4 and high saline concentration. While most of these papers report that PBnp are stable at this pH, a small number of papers describes instead PBnp degradation at the same or similar pH values, i.e. in the 7–8 range. Here we give a definitively clear picture: PBnp are intrinsically unstable at pH ≥ 7, degrading with the fast disappearance of their 700 nm absorption band, due to the formation of OH- complexes from the labile Fe3+ centers. However, we show also that the presence of a polymeric coating (PVP) can protect PBnp at pH 7.4 for over 24 h. Moreover, we demonstrate that when “physiological conditions” include serum, a protein corona is rapidly formed on PBnp, efficiently avoiding degradation. We also show that the viability of PBnp-treated EA.hy926, NCI-H1299, and A549 cells is not affected in a wide range of conditions that either prevent or promote PBnp degradation.

Plasma-Induced Oxygen Vacancies in N-Doped Hollow NiCoPBA Nanocages Derived from Prussian Blue Analogue for Efficient OER in Alkaline Media.

Although water splitting is a promising method to produce clean hydrogen energy, it requires efficient and low-cost catalysts for the oxygen evolution reaction (OER). This study focused on plasma treatment's significance of surface oxygen vacancies in improving OER electrocatalytic activity. For this, we directly grew hollow NiCoPBA nanocages using a Prussian blue analogue (PBA) on nickel foam (NF). The material was treated with N plasma, followed by a thermal reduction process for inducing oxygen vacancies and N doping on the structure of NiCoPBA. These oxygen defects were found to play an essential role as a catalyst center for the OER in enhancing the charge transfer efficiency of NiCoPBA. The N-doped hollow NiCoPBA/NF showed excellent OER performance in an alkaline medium, with a low overpotential of 289 mV at 10 mA cm-2 and a high stability for 24 h. The catalyst also outperformed a commercial RuO2 (350 mV). We believe that using plasma-induced oxygen vacancies with simultaneous N doping will provide a novel insight into the design of low-priced NiCoPBA electrocatalysts.

Electrochemical Mercury Biosensor Based on Electrocatalytic Properties of Prussian Blue and Inhibition of Catalase

This paper presents a detailed study of a novel type of electrochemical mercury ion (Hg2+) biosensor developed by combining Prussian blue (PB) and catalase (Cat). The simultaneous PB-catalyzed reduction of hydrogen peroxide and the inhibition of catalase by Hg2+ ions were used as the working principle of the biosensor. The biosensor described in this research was capable of detecting Hg2+ ions at relatively low potentials (+0.2 V vs. Ag|AgCl, KClsat) using chronoamperometry and a fast Fourier transform electrochemical impedance spectroscopy (FFT-EIS). Linear ranges of 0.07 mM–3 mM and 0.13 mM–0.80 mM of Hg2+ ions were obtained using amperometric and impedimetric techniques, respectively. In the course of this work, an amperometric study of the Hg2+ ion biosensor was also carried out on a real sample (tap water containing Hg2+ ions).

Surface-engineered prussian blue nanozymes as artificial receptors for universal pattern recognition of metal ions and proteins

Pattern-based array sensing have emerged as an efficient and promising approach for detection of multiple analytes; however, it is still challenging but important to synthesize a range of materials as sensing elements. Surface engineering is a promising strategy for activity modulation or functional design for novel nanomaterials. Herein, we fabricate three Prussian blue (PB)-based nanomaterials by surface modification (pristine PB, PB@MoS2, and PB@Pt), which have exhibited distinct peroxidase-like activities due to varying surfaces. The three PB-based nanozymes have been successfully employed as artificial receptors to construct a cross-reactive colorimetric sensor array. According to the differential interactions between targets and the surface of PB-based nanozymes, the presented sensor array can achieve unique colorimetric response patterns and precisely discriminate 10 metal ions and 13 proteins. This sensor array is sufficiently sensitive to quantitatively analyze individual metal ion and protein with detection limit down to µM and µg/mL, respectively. Moreover, the recognition of metal ions and proteins in complex mixtures has also been achieved. Most importantly, the practical applications have been demonstrated by identifying metal ions in tap water and proteins in human serum samples, differentiating denatured and natural proteins, distinguishing blind samples, and even discriminating clinical samples for cancer identification. This work demonstrates an effective strategy of surface engineering of nanozyme for activity modulation, as well as shows a convenient and universal chemical tongue sensing platform.

Supercritical-Assisted Ball-Milling Synthesis of Multicomponent Si/Fe3O4/C Composites for Outstanding Lithium-Storage Capability

Attributed to high theoretical capacity and abundant reserves, Si/C anodes have been commercialized in lithium-ion batteries (LIBs). However, the shortcomings of poor interfacial compatibility, low rate performance, and bad stability remain to be overcome. In this paper, a facile method for the synthesis of silicon/iron oxide/carbon (Si/Fe3O4/C) composites by ball-milling in a supercritical carbon dioxide (scCO2) fluid medium is proposed. This method utilizes the diffusion characteristics, extremely low viscosity, and excellent mass transfer properties of supercritical fluids. Under the infiltration of an scCO2 fluid, mesophase carbon microspheres (MCMB) are exfoliated into graphite flakes and achieve good interfacial fusion with silicon and Prussian blue during ball-milling. The Prussian blue is transformed into Fe3O4 by subsequent heat treatment under a nitrogen atmosphere, and Fe3O4 introduced in this way enhances the lithium-storage capacity, cycling stability, and rate performance significantly of Si/C anodes. As an anode for LIBs, the reversible capacity of Si/Fe3O4/C reaches 1363 mA h g–1 after 600 cycles at 1 A g–1. This study provides an idea for the design and fabrication of Si-based anode materials with high capacity and long cycle life.

Glyoxylic-Acetal-Based Electrolytes for Sodium-Ion Batteries and Sodium-Ion Capacitors.

A comprehensive study on the properties and implementation of glyoxylic-acetals in sodium-ion energy storage systems is presented. Electrolytes containing 1,1,2,2-tetramethoxyethane (tetramethoxyglyoxal, TMG), 1,1,2,2-tetraethoxyethane (tetraethoxyglyoxal, TEG) and a mixture of the latter with propylene carbonate (PC) exhibit increased thermal stabilities and higher flash points compared to classical electrolytes based on carbonates as solvents. Due to its favorable properties, 1 m NaTFSI in TEG/PC (3 : 7), has been selected and used for sodium-ion energy storage systems based on a Prussian Blue (PB) positive electrode and a hard carbon (HC) negative electrode. Compared to conventional electrolyte (based on a 1 : 1 mixture of ethylene carbonate, EC, and dimethyl carbonate, DMC), this glyoxylic-acetal electrolyte provides competitive capacity and prolonged cycle life. Postmortem XPS analysis indicates that the electrode-electrolyte interphases formed in presence of TEG are thicker and presumably more protective, inhibiting typical degradation processes of the electrodes. Furthermore, it is demonstrated that the suitable properties of TEG on the cycling stability can also be exploited for the construction of highly stable sodium-ion capacitors.

Rapid and versatile colorimetric sensor based on luminescent bacterium for water comprehensive toxicity detection

In this study, a high-efficiency colorimetric sensor for water toxicity assessment was successfully constructed by the visual analysis with naked eyes and the high-throughput measurement with a microplate reader. The bioluminescent Photobacterium phoshoreum T3 spp. (T3) and Prussian blue (PB) were used as model bacterium and indicator of the colorimetric sensor, respectively. In order to accurately detect acute toxicities of wastewater, the experimental conditions, concentrations of cells, K3[Fe(CN)6] and NaCl, reaction temperature and time, were optimized to be OD600 = 2, 8 mM, 1.2%, 26.5 °C and 25 min, respectively. Then several samples of simulated wastewater containing Hg2+, Cd2+, Zn2+, 3,5-dichlorophenol (DCP) and formaldehyde (HCHO) were tested. The composite biotoxicity of dry battery leachate and real water sample was also evaluated. The IC50 values of Hg2+, Cd2+, Zn2+ and DCP obtained were 3.60, 1.56, 0.96 and 11.77 mg L−1, respectively. Moreover, a toxic unit (TU) model was applied to evaluate the binary complex toxicity of Hg2+ + Cd2+, Hg2+ + Zn2+ and DCP + Zn2+, which showed antagonistic effects. The work demonstrates that the promising high-efficiency sensor can detect quickly and sensitively the single and joint toxicities of multi-pollutants in water, which possesses extensive potentials in field of toxicity detection.

Antioxidation and Anti-Inflammatory Activity of Prussian Blue Nanozymes to Alleviate Acetaminophen-Induced Acute Liver Injury

Acetaminophen (APAP), a common antipyretic and analgesic drug, is considered the most common cause of drug-induced liver injury (DILI). The mechanism of liver injury induced by APAP is mainly related to oxidative stress and inflammatory reaction. Herein, we report a simple and efficient one-step synthesis of Prussian blue (PB) nanozymes with multiple antioxidant enzymatic activities that effectively treat APAP-induced DILI. At the cellular level, reaching 10 μg/mL PB nanozymes can effectively scavenge intracellular reactive oxygen species (ROS), reduce mitochondrial membrane potential drop, and inhibit hepatocyte apoptosis. According to in vivo experimental studies, the levels of serum biochemical indicators and histopathological examination of DILI mice livers showed that 12.5 mg/kg PB nanozymes could effectively inhibit liver necrosis and 25 mg/kg PB nanozymes achieved the same therapeutic effect as 300 mg/kg NAC. More importantly, compared with NAC, PB nanozymes can still attenuate APAP-induced acute liver injury in mice after APAP-induced acute liver injury in mice for 3 h. Therefore, PB nanozymes can effectively prolong the therapeutic time window, revealing the potential of PB nanozymes in clinical applications for advanced DILI treatment. Furthermore, the therapeutic mechanism studies have shown that PB nanozymes with abundant and variable valence states could not only directly scavenge ROS but also through the Keap1-Nrf2/HO-1 pathway to reduce oxidative stress. Moreover, the decreased expression levels of myeloperoxidase and F4/80 in the liver, which are markers of neutrophil and macrophage infiltration, indicated that the Prussian blue nanozymes modulates inflammation to protect against APAP-induced acute liver injury. Consequently, our findings suggested that PB nanozymes have excellent clinical application prospects for acetaminophen-induced acute liver injury.

Continuous Production of High-Capacity Iron-Based Prussian Blue Sodium-Ion Cathode Materials Using a Rotor–Stator Spinning Disk Reactor

Iron-based Prussian blue materials have the potential to be used as low-cost, simple-to-synthesize, and high-capacity cathode materials for large-scale energy storage sodium-ion batteries. However, in order to obtain high-capacity sodium storage Prussian blue materials, the currently used high-energy hydrothermal method or interstitial coprecipitation method is difficult to meet large-scale energy storage applications. The electrochemical performance of the product is highly dependent on the crystallization process. In this work, a simple stator–rotor reactor (RSSDR) reactor and precipitation transformation were used to improve the crystallization and precipitation process of iron-based Prussian blue, and continuous production was realized. The effects of particles with different morphologies on the products after aging were investigated, and the specific capacity (162.4 mAh g–1 at 34 mA g–1) and cycle retention rate (capacity retention of 64.97% for 200 cycles at the current density of 170 mA g–1) of iron-based Prussian blue were improved. Overall, this work provides a strategy to continuously produce iron-based Prussian blue sodium-ion cathode materials with improved electrochemical performance through improving the crystallization process.

Preparation of paramagnetic ferroferric oxide-calcined layered double hydroxide core–shell adsorbent for selective removal of anionic pollutants

Adsorption is one of the most common methods of pollution treatment. The selectivity for pollutants and recyclability of adsorbents are crucial to reduce the treatment cost. Layered double hydroxide (LDH) materials are one type of adsorbent with poor recyclability. Prussian blue (PB) is a sturdy and inexpensive metal–organic framework material that can be used as the precursor for synthesizing paramagnetic ferroferric oxide (Fe3O4). It is intriguing to build some reusable adsorbents with magnetic separation by integrating LDH and PB. In this work, paramagnetic Fe3O4-calcined LDH (Fe3O4@cLDH) core–shell adsorbent was designed and prepared by the calcination of PB-ZnAl layered double hydroxide (PB@LDH) core–shell precursor, which exhibits high anionic dyes selectivity in wastewater solutions. The paramagnetism and adsorption capability of Fe3O4@cLDH come from the Fe3O4 core and calcined ZnAl-LDH shell, respectively. Fe3O4@cLDH shows an adsorption capacity of 230 mg g−1 for acid orange and a high selectivity for anionic dyes in cation–anion mixed dye solutions. The regeneration process indicates that the high selectivity for anions is related to the specific hydration recovery process of ZnAl-LDH. The synergistic effect of the paramagnetic Fe3O4 core and calcined ZnAl-LDH shell makes Fe3O4@cLDH an excellent magnetic separation adsorbent with high selectivity to anions.

Pulse Power Generation Chronoamperometry as an Advanced Readout for (Bio)sensors: Application for Noninvasive Diabetes Monitoring.

We propose pulse power generation (PPG) amperometry as an advanced readout realized for Prussian blue (PB)-based (bio)sensors. In contrast to the conventional power generation mode, when the current response is generated upon continuous short-circuiting, the suggested pulse regime is fulfilled by periodic opening and shorting of the circuit. Despite PB being electroactive, the pulse readout is advantageous over conventional steady-state power generation, providing up to a 15-fold increased signal-to-background ratio as well as dramatically improved sensitivity exceeding 10 A·M-1·cm-2 for H2O2 sensors and 3.9 A·M-1·cm-2 for glucose biosensors. Such analytical performance characteristics are, most probably, achieved due to the enrichment of the diffusion layer by analyte mass transfer from the bulk upon opening of the circuit. Due to an improved sensitivity-to-background ratio, reduced flow-rate dependence, and enhanced operational stability, the regime allows reliable monitoring of blood glucose variations through sweat analysis with the on-skin device.

The Synergistic Effect of Ruthenium Complex Δ-Ru1 and Doxorubicin in a Mouse Breast Cancer Model.

Doxorubicin is a significant drug for the treatment of breast cancer, but its cardiotoxicity is an obvious obstacle. Previously, we confirmed that ruthenium complex (Δ-Ru1) and doxorubicin (Δ-Ru1/Dox) combination had a synergistic effect in MCF-7 cells, but its biological effect in vivo is unknown. To find a way to overcome the toxicity of doxorubicin and build MCF-7 xenograft tumor mouse model to test whether this potential combination has better efficacy and less toxicity. The tumor model of nude mice was established to verify the synergistic antitumor effect of the drug combination in vivo. H&E staining was used to detect the toxicity of major organs in mice. Sirius red staining and transmission electron microscopy were used to detect cardiotoxicity. Prussian blue was used to measure iron accumulation in heart tissue. TUNEL staining was used to detect the antitumor effect in vivo. Immunohistochemical staining was used to detect the expression of iron death-related pathway proteins. High-throughput sequencing techniques were used to determine the molecular mechanism of ferroptosis. Histopathological analysis of tumor tissues indicated that the Δ-Ru1/Dox combination significantly promoted tumor cell apoptosis. Doxorubicin damaged cardiac tissue by inducing fibrosis and iron accumulation, but it was reversed by the Δ-Ru1/Dox combination treatment. Further exploration found that doxorubicin could regulate iron accumulation in the ferroptosis pathway and the expression of lipid peroxidation-related proteins, including upregulation of Tf, DMT1, and HO-1, and downregulation of Nrf2, SLC7A11, and GPX4. Δ-Ru1/Dox combination synergistically inhibits tumor growth, and it can significantly reduce and alleviate the toxic side effects of doxorubicin, especially cardiac injury.

In Situ Prussian Blue-Electrocatalyst Formation on Intrinsic Iron-Containing Pristine-MWCNT as a Template and Its EQCM and SECM Interrogations and Batch Injection Analysis of Hydrogen Peroxide

Herein, we report in-situ electrochemical derivatization of the intrinsic iron species in a pristine-multiwalled carbon nanotube (MWCNT) as Prussian blue (PB) modified MWCNT hybrid (MWCNT@PB) using a dilute solution of ferricyanide as a derivatization agent in pH 2 HCl-KCl solution. The PB hybrid system showed a defined redox peak at an apparent standard electrode potential, Eo’ = 0.18 V vs Ag/AgCl with an excess surface value, 1.71 × 10−10 mol cm−2. A discreet EQCM study on the electrochemical preparation of MWCNT@PB using MWCNT and ferricyanide precursors reveal the specific stripping of iron species and uptake of iron species, potassium and ferricyanide ions upon the electrochemical preparation condition. In-situ imaging of MWCNT@PB was carried out using SECM with ferricyanide as a redox mediator under a feedback-current mode. It has been identified that a mixed-potential based electrochemical reaction involving oxidative stripping of iron to iron ion species (step-1) coupled with reduction of ferricyanide to ferrocyanide (step-2) followed by a chemical interaction between the iron ion and ferricyanide (step-3) have occurred for the overall formation of MWCNT@PB hybrid. Electrocatalytic and electroanalytical performance of the MWCNT@PB hybrid towards H2O2 reduction and sensing were demonstrated by performing cyclic voltammetric, amperometric i-t and batch injection analysis.