Sequential electrodeposition of Cu–Pt bimetallic nanocatalysts on boron-doped diamond electrodes for the simple and rapid detection of methanol
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2021-07-13 |
| Journal | Scientific Reports |
| Authors | Surinya Traipop, Abdulhadee Yakoh, Sakda Jampasa, Sudkate Chaiyo, Yuttanant Boonyongmaneerat |
| Institutions | Chulalongkorn University |
| Citations | 10 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled “Executive Summary”- Novel Sensor Architecture: A highly effective electrochemical sensor for methanol (MetOH) detection was developed using sequential electrodeposition of Cu-Pt bimetallic nanocatalysts onto a Boron-Doped Diamond (BDD) electrode (Cu/Pt/BDD).
- Synergistic Catalysis: The Pt base layer provides high electrocatalytic activity, while the subsequent Cu layer enhances conductivity and, critically, suppresses the adsorption of carbonaceous intermediates (CO poisoning), leading to superior long-term stability.
- Optimized Morphology: Sequential deposition (Pt first, then Cu) resulted in a favorable flower-like Pt structure covered by Cu particles, maximizing the active surface area and promoting MetOH oxidation.
- Enhanced Sensitivity via SIA: Coupling the sensor with a Sequential Injection Analysis (SIA) system improved the detection limit by approximately 100 times compared to traditional Cyclic Voltammetry (CV).
- High Performance Metrics: The sensor achieved a low Limit of Detection (LOD) of 83 µM (S/N = 3) and demonstrated a remarkably wide linear range spanning 0.1 mM up to 1000 mM.
- Robustness and Applicability: The sensor exhibited excellent stability (92% signal retention after 2 weeks) and high selectivity, successfully applied for MetOH detection in complex fruit and vegetable beverage samples.
Technical Specifications
Section titled “Technical Specifications”| Parameter | Value | Unit | Context |
|---|---|---|---|
| Limit of Detection (LOD) | 83 | µM | S/N = 3, Low concentration range |
| Linear Range (Low) | 0.1 to 10 | mM | High sensitivity region |
| Linear Range (High) | 10 to 1000 | mM | Wide dynamic range |
| Sensitivity (Low Range) | 0.829 | µA/mM | 0.1-10 mM MetOH |
| Sensitivity (High Range) | 0.229 | µA/mM | 10-1000 mM MetOH |
| Pt Deposition Potential | -0.4 | V | vs Ag/AgCl |
| Cu Deposition Potential | -0.5 | V | vs Ag/AgCl |
| Pt Deposition Time | 600 | s | Optimized multiple-step deposition |
| Cu Deposition Time | 900 | s | Optimized one-step deposition |
| Supporting Electrolyte | 0.1 | M | NaOH (Optimized for alkaline oxidation) |
| Reproducibility (RSD) | 3.2 | % | Five independently fabricated electrodes |
| Storage Stability | 2 | weeks | 92% signal retained at room temperature |
| BDD Doping Level | 10,000 | ppm | Boron |
| BDD Geometric Area | 0.07 | cm2 | Working electrode area |
Key Methodologies
Section titled “Key Methodologies”- BDD Electrode Pre-treatment: The BDD substrate was pre-treated via potentiostatic anodic polarization in 0.1 M H2SO4 at 2.0 V for 5 minutes to eliminate adsorbed hydrogen and undesirable sp2 graphitic carbon phases, reducing background current.
- Pt Base Layer Deposition: Platinum was deposited first using a multiple-step electrodeposition technique (optimized for better dispersion and morphology) from 1 mM K2[PtCl4] in 0.1 M H2SO4. The process involved applying a deposition potential of -0.4 V and a relaxation potential of 0.0 V for 600 s.
- Cu Top Layer Deposition: Copper was subsequently deposited onto the Pt/BDD electrode using a one-step electrodeposition technique from 1 mM Cu(CH3COO)2 in 0.1 M CH3COONa. The optimized deposition potential was -0.5 V for 900 s.
- Morphological and Chemical Characterization:
- Scanning Electron Microscopy (SEM) confirmed the resulting Cu/Pt/BDD structure featured flower-like Pt microclusters covered by Cu particles, providing high surface area.
- X-ray Photoelectron Spectroscopy (XPS) confirmed the presence of metallic Pt0 and/or Pt-Cu alloy, indicating electronic coupling between the metals.
- Electrochemical Characterization: Electrochemical Impedance Spectroscopy (EIS) confirmed the Cu/Pt/BDD electrode had the lowest charge transfer resistance (Rct = 14.8 kΩ) and highest conductivity among all tested configurations.
- Automated Analysis: The Cu/Pt/BDD sensor was integrated into a Sequential Injection Analysis (SIA) system, and methanol detection was performed using chronoamperometry at an applied potential of 0.5 V vs Ag/AgCl in 0.1 M NaOH.
Commercial Applications
Section titled “Commercial Applications”- Food and Beverage Quality Control: Rapid, high-throughput screening for trace methanol contamination in fruit juices, vegetable beverages, coffee, and fermented products, ensuring consumer safety.
- Chemical and Fuel Cell Industries: Monitoring and control of methanol oxidation reactions (MOR) kinetics, particularly in direct methanol fuel cells (DMFCs), where catalyst poisoning is a major challenge.
- Environmental Safety: Detection of methanol in industrial effluent and wastewater streams, leveraging the sensor’s low detection limit and robustness.
- Non-Enzymatic Sensing: Development of stable, long-life sensors for alcohol detection, bypassing the thermal and chemical instability issues associated with traditional enzyme-based electrodes.
- Automated Laboratory Testing: Utilizing the SIA integration for high-efficiency, automated analysis in regulatory or industrial laboratories requiring precise control and high sample throughput.