Lanthanum Ferrite Ceramic Powders - Synthesis, Characterization and Electrochemical Detection Application

At a Glance

Metadata	Details
Publication Date	2020-04-29
Journal	Materials
Authors	Raluca Dumitru, Sorina Negrea, Adelina Ianculescu, Cornelia Păcurariu, Bogdan Ştefan Vasile
Institutions	Polytechnic University of Timişoara, University of Bucharest
Citations	22
Analysis	Full AI Review Included

Technical Documentation & Analysis: LaFeO₃/BDD for Electrochemical Sensing

This document analyzes the research concerning the synthesis and application of Lanthanum Ferrite (LaFeO₃) ceramic powders used to modify Boron-Doped Diamond (BDD) electrodes for the detection of capecitabine (CCB). This application highlights the critical role of high-quality BDD substrates in advanced electrocatalytic sensing.

Executive Summary

Core Achievement: Successful synthesis of nanometric LaFeO₃ perovskite powders (optimal size <20 nm) via thermal decomposition of an oxalate precursor.
Electrode System: A commercial Boron-Doped Diamond (BDD) electrode was modified by simple immersion in the optimal LaFeO₃ powder (calcined at 550 °C).
Electrocatalytic Performance: The LaFeO₃/BDD electrode exhibited strong electrocatalytic activity toward both the oxidation and reduction of capecitabine (CCB) in alkaline aqueous solution (0.1 M NaOH).
Superior Sensitivity: Differential-Pulsed Voltammetry (DPV) achieved a remarkably low Limit of Detection (LOD) of 0.010 µM for CCB reduction, demonstrating superior performance compared to other carbon-based electrodes (e.g., Glassy Carbon: 0.113 µM).
Detection Flexibility: Multiple-Pulsed Amperometry (MPA) confirmed the ability to detect CCB simultaneously via both reduction (-1.1 V/SCE) and oxidation (-0.4 V/SCE) mechanisms.
Material Requirement: The high electrochemical stability and wide potential window of the BDD substrate were essential for manifesting the complex redox systems of the LaFeO₃ modifier.

Technical Specifications

The following hard data points were extracted from the characterization and electrochemical testing of the LaFeO₃/BDD system:

Parameter	Value	Unit	Context
Optimal Calcination Temperature	550	°C	Used for LaFeO₃ powder modification
Average Crystallite Size (550 °C)	17.5	nm	Determined via XRD Rietveld analysis
Average Particle Size (550 °C)	<20	nm	Estimated via FE-SEM/TEM
BDD Substrate Boron Content	~0.1	N/A	Commercial BDD specification
Supporting Electrolyte	0.1 M	NaOH	Alkaline aqueous solution
Lowest Limit of Detection (LOD)	0.010	µM	Achieved via DPV (CCB reduction)
DPV Sensitivity (Low Range)	111.0	µA µM^-1 cm^-2	CCB concentration < 2.5 µM
CV Sensitivity (CCB Oxidation)	0.257	µA µM^-1 cm^-2	At -0.40 V/SCE
MPA Sensitivity (CCB Reduction)	3.040	µA µM^-1 cm^-2	At -1.1 V/SCE
CV Potential Scan Rate	0.05	V s^-1	Used for electrochemical characterization

Key Methodologies

The experimental procedure focused on controlled synthesis of the perovskite material and subsequent modification of the diamond electrode:

Precursor Synthesis:
- The LaFe(C₂O₄)₃·3H₂O oxalate precursor was synthesized in situ using a redox reaction involving lanthanum nitrate, iron nitrate, 1,2-ethanediol, and 2 M nitric acid.
- Molar ratio used: 1:1:3:2 (La:Fe:Ethylene Glycol:HNO₃).
- Reaction conditions: Heated for 20 min at 100 °C in a water bath, maintaining a solution pH of 3.
LaFeO₃ Powder Generation:
- The purified precursor was calcinated in air across a temperature range of 550 °C to 800 °C.
- Heating rate: 10 °C min^-1 for a duration of 1 hour.
- Result: Single-phase LaFeO₃ powders with orthorhombic Pbnm structure were obtained. The 550 °C powder exhibited the smallest particle size (<20 nm) and highest aggregation tendency.
Electrode Modification:
- A commercial Boron-Doped Diamond (BDD) electrode was used as the working substrate.
- Modification method: Simple immersion in a 5 mg mL^-1 suspension of the optimal LaFeO₃ powder (calcined at 550 °C).
Electrochemical Detection:
- A classical three-electrode cell was employed (Saturated Calomel Electrode (SCE) reference, Platinum counter-electrode).
- Techniques utilized: Cyclic Voltammetry (CV), Differential-Pulsed Voltammetry (DPV), and Multiple-Pulsed Amperometry (MPA).
- Electrolyte: 0.1 M sodium hydroxide (NaOH).

6CCVD Solutions & Capabilities

The successful development of this high-sensitivity electrochemical sensor relies fundamentally on the quality and stability of the Boron-Doped Diamond substrate. 6CCVD is uniquely positioned to supply and enhance the critical diamond components required for replicating and advancing this research.

Applicable Materials

To replicate or extend this research, 6CCVD recommends the following materials, offering superior control over the substrate properties compared to commercial off-the-shelf options:

Heavy Boron Doped PCD (Polycrystalline Diamond): Essential for high conductivity and the wide potential window necessary for detecting both CCB oxidation and reduction. We offer precise control over boron doping levels to optimize the Fe²⁺/Fe³⁺ and Fe³⁺/Fe⁴⁺ redox systems observed in the LaFeO₃ layer.
Optical Grade SCD (Single Crystal Diamond): For applications requiring the highest surface uniformity and lowest defect density, SCD provides an ideal platform for highly reproducible thin-film deposition of the LaFeO₃ catalyst.

Customization Potential

The research used a simple immersion technique for modification. 6CCVD’s capabilities allow researchers to move beyond simple immersion to highly controlled, scalable manufacturing processes:

Research Requirement / Limitation	6CCVD Customization Service	Technical Advantage
Substrate Size Limitation (Commercial BDD used)	Custom Dimensions up to 125mm (PCD). We supply large-area wafers suitable for high-density sensor arrays.	Enables industrial scale-up and mass production of environmental monitoring devices.
Simple Immersion Modification (Low reproducibility)	Ultra-Smooth Polishing (Ra < 1nm SCD, < 5nm PCD). Provides an atomically flat surface for advanced deposition techniques.	Allows for uniform, high-quality thin-film deposition (e.g., sputtering or CVD) of LaFeO₃, ensuring superior adhesion and sensor longevity compared to powder suspension.
Electrode Integration	Internal Metalization Services. We offer deposition of Au, Pt, Pd, Ti, W, and Cu contacts directly onto the BDD surface.	Facilitates seamless integration into microfluidic or chip-based electrochemical systems, eliminating external wiring complexity.
Thickness Optimization	Custom Thickness Control. BDD layers available from 0.1 µm (thin film) up to 500 µm (thick plate) on various substrates (up to 10mm).	Allows engineers to tune the thermal and electrical properties of the electrode for specific operating environments (e.g., high-power or high-frequency sensing).

Engineering Support

The successful detection of emerging pollutants like Capecitabine (CCB) requires precise material engineering. 6CCVD’s in-house PhD team specializes in the electrochemical properties of diamond and can assist researchers and engineers with:

Doping Optimization: Selecting the exact boron concentration and doping profile necessary to maximize the electrocatalytic effect of the LaFeO₃ modifier.
Surface Preparation: Consulting on optimal polishing and cleaning protocols to ensure maximum adhesion and uniformity for subsequent perovskite deposition.
Custom Geometry: Designing and laser-cutting BDD electrodes into unique shapes or patterns required for specific cell geometries or micro-sensor applications.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

The perovskite-type lanthanum ferrite, LaFeO3, has been prepared by thermal decomposition of in situ obtained lanthanum ferrioxalate compound precursor, LaFe(C2O4)3·3H2O. The oxalate precursor was synthesized through the redox reaction between 1,2-ethanediol and nitrate ion and characterized by chemical analysis, infrared spectroscopy, and thermal analysis. LaFeO3 obtained after the calcination of the precursor for at least 550-800 °C/1 h have been investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). A boron-doped diamond electrode (BDD) modified with LaFeO3 ceramic powders at 550 °C (LaFeO3/BDD) by simple immersion was characterized by cyclic voltammetry and tested for the voltammetric and amperometric detection of capecitabine (CCB), which is a cytostatic drug considered as an emerging pollutant in water. The modified electrode exhibited a complex electrochemical behaviour by several redox systems in direct relation to the electrode potential range. The results obtained by cyclic voltammetry (CV), differential-pulsed voltammetry (DPV), and multiple-pulsed amperometry proved the electrocatalytic effect to capecitabine oxidation and reduction and allowed its electrochemical detection in alkaline aqueous solution.

Tech Support

Original Source

DOI: https://doi.org/10.3390/ma13092061

References

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