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6CCVD Research

The Mediatorless Electroanalytical Sensing of Sulfide Utilizing Unmodified Graphitic Electrode Materials

At a Glance

Section titled “At a Glance”
MetadataDetails
Publication Date2016-04-16
JournalC – Journal of Carbon Research
AuthorsBhawana Thakur, Elena Bernalte, J. L. Smith, Patricia Linton, Shilpa N. Sawant
InstitutionsUniversidad de Extremadura, Manchester Metropolitan University
Citations14
AnalysisFull AI Review Included

Technical Analysis & Documentation: MPCVD Diamond for Electroanalytical Sensing

Section titled “Technical Analysis & Documentation: MPCVD Diamond for Electroanalytical Sensing”

Executive Summary

Section titled “Executive Summary”

This documentation analyzes the performance of Boron-Doped Diamond Electrodes (BDDE) in the mediatorless electroanalytical sensing of sulfide, highlighting the material limitations identified in the research and presenting 6CCVD’s capabilities to overcome these challenges.

  • Research Focus: Comparative study of unmodified carbon-based electrodes (including BDDE) for the direct, mediatorless electrochemical oxidation of sulfide (HS- $\rightarrow$ S + 2e- + H+).
  • BDDE Performance: The BDDE exhibited the lowest electrochemical reactivity among the tested materials (BDDE < GCE, SPE), characterized by the highest oxidation potential (+0.84 V vs. SCE) and the slowest inner-sphere electron transfer kinetics ($\Delta E_p$ = 1162 mV for Fe2+/Fe3+).
  • Material Limitation: The poor performance of the BDDE was attributed to its highly stable, defect-free surface, which lacks the necessary edge sites or defects crucial for facilitating the inner-sphere redox mechanism required for sulfide oxidation.
  • 6CCVD Value Proposition: 6CCVD specializes in engineering MPCVD Boron-Doped Diamond (BDD) with precise control over doping levels, surface termination, and defect density, enabling the creation of BDD electrodes optimized for specific electrocatalytic applications.
  • Customization Potential: We offer BDD substrates with tailored surface treatments (e.g., specific termination or controlled defect introduction) to enhance the electroanalytical signal, directly addressing the reactivity shortcomings observed in the commercial BDDE used in this study.
  • Scalability: 6CCVD provides BDD wafers up to 125 mm (PCD), facilitating the scale-up of successful lab-bench experiments into high-volume, disposable sensor platforms, similar to the Screen-Printed Electrodes (SPEs) favored in the paper.

Technical Specifications

Section titled “Technical Specifications”

The following data points summarize the key electrochemical parameters observed, focusing on the Boron-Doped Diamond Electrode (BDDE) performance.

ParameterValueUnitContext
BDDE Sulfide Oxidation Potential+0.84Vvs. SCE, measured at pH 8
BDDE Current Density (Sulfide)~100”Acm-11 mM Sulfide, pH 8 (Figure 1A)
Optimal Sensing pH8-Britton-Robinson buffer
Scan Rate (Cyclic Voltammetry)100mV·s-1Standard measurement rate
BDDE Heterogeneous Electron Transfer Rate (kÂș)3.92 x 10-3cm·s-1Outer-sphere probe (Hexaammineruthenium(III) Chloride)
BDDE Peak Separation ($\Delta E_p$)120mVOuter-sphere probe (Hexaammineruthenium(III) Chloride)
BDDE Peak Separation ($\Delta E_p$)1162mVInner-sphere probe (Ammonium Iron(II) Sulfate)
BDDE Limit of Detection (LOD)37.5”MCalculated based on 3$\sigma$
BDDE Reactivity OrderLowest-SPE > EPPGE > GCE > BDDE > BPPGE

Key Methodologies

Section titled “Key Methodologies”

The electroanalytical performance of the BDDE and other carbon electrodes was rigorously benchmarked using standard electrochemical techniques.

  1. Electrode Selection: Five commercially available carbon-based electrodes were tested: Edge Plane Pyrolytic Graphite (EPPGE), Basal Plane Pyrolytic Graphite (BPPGE), Glassy Carbon (GCE), Screen-Printed Electrodes (SPE), and Boron-Doped Diamond (BDDE).
  2. Electrode Pretreatment: BDDE and GCE surfaces were polished using alumina of decreasing sizes on soft lapping pads to ensure a clean, reproducible surface prior to measurement.
  3. Benchmarking: Electrodes were characterized using two standard redox probes to assess surface electronic structure and reactivity:
    • Outer-Sphere Probe: 1 mM Hexaammineruthenium(III) Chloride/0.1 M KCl (sensitive to electronic structure).
    • Inner-Sphere Probe: 1 mM Ammonium Iron(II) Sulfate/0.2 M HClO4 (sensitive to surface functional groups/defects).
  4. Sulfide Sensing Conditions: Cyclic Voltammetry (CV) was performed in a three-electrode system (BDDE working electrode, Nickel wire counter, SCE reference).
  5. Solution Optimization: Sulfide sensing was optimized at pH 8 using a Britton-Robinson buffer, corresponding to the dominance of the mono-protonated sulfide anion (HS-).
  6. Passivation Study: GCE was found to be susceptible to sulfide passivation, requiring polishing between measurements. SPEs were utilized as disposable, one-shot sensors to circumvent this issue.

6CCVD Solutions & Capabilities

Section titled “6CCVD Solutions & Capabilities”

The research demonstrates that the performance of BDD in electroanalysis is highly dependent on surface characteristics (edge sites, defects, and termination). 6CCVD’s MPCVD expertise allows us to engineer BDD substrates that directly address the limitations found in the commercial BDDE used in this study, providing superior materials for advanced sensor development.

Research Requirement/Limitation6CCVD Solution & CapabilityTechnical Advantage for Replication/Extension
Material Used: Boron-Doped Diamond (BDDE)Heavy Boron-Doped Diamond (BDD) Substrates. We supply high-quality MPCVD BDD (SCD or PCD) with precise, tunable doping levels (up to 1021 atoms/cm3) to guarantee optimal conductivity and electrochemical stability.Ensures highly reproducible, low-background current electrodes essential for sensitive electroanalytical measurements.
Limitation: BDDE exhibited low reactivity (kÂș = 3.92 x 10-3 cm·s-1) due to lack of edge sites/defects, hindering inner-sphere sulfide oxidation.Custom Surface Engineering and Defect Control. 6CCVD can tailor the BDD growth recipe to control grain size and introduce specific defect densities, enhancing the electrocatalytic activity required for inner-sphere reactions like sulfide oxidation.Directly overcomes the material limitation identified in the paper, allowing researchers to achieve higher current densities and lower oxidation potentials than the commercial BDDE tested.
Dimensions Used: 3 mm diameter BDDECustom Dimensions up to 125 mm. We offer PCD wafers up to 125 mm and SCD plates up to 500 ”m thick, allowing for seamless scale-up from R&D to commercial production of large-format sensor arrays.Supports the transition to high-volume, disposable sensor platforms (like the SPEs favored in the study) using robust diamond material.
Electrode Integration: Need for robust electrical connection and potential modification (e.g., nano-copper modification mentioned in Table 1).In-House Metalization Services. We provide custom metal contacts (Au, Pt, Pd, Ti, W, Cu) applied directly to the diamond surface, ensuring secure electrical wiring and facilitating subsequent modification steps.Enables reliable integration of BDD into complex electrochemical cells or screen-printed configurations.
Engineering Support: Need for material selection and optimization for similar sulfide sensing projects.Expert Engineering Support. 6CCVD’s in-house PhD team specializes in diamond material science and electrochemistry, offering consultation on material selection, doping optimization, and surface termination for similar Electroanalytical Sensing projects.Accelerates R&D cycles by providing materials precisely engineered for the target application.

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

View Original Abstract

The mediatorless electroanalytical sensing of sulfide is explored at a range of commercially available graphitic based electrodes namely, edge and basal plane pyrolytic graphite (EPPGE and BPPGE, respectively), boron-doped diamond (BDDE), glassy carbon (GCE) and screen-printed electrodes (SPE). The electrochemical performance is evaluated in terms of current density/analytical signal and oxidation potential, where the GCE and SPE are found to possess the optimal electrochemical responses. The electroanalytical performance of the GCE is explored towards the electrochemical sensing of sulfide and it is found that it is hampered by sulfide passivation, thus requiring pretreatment in the form of electrode polishing between each measurement. We demonstrate that SPEs provide a simple analytically comparable alternative, which, due to their scales of economy, create disposable, one-shot sensors that do not require any pretreatment of the electrode surface. To the best of our knowledge, this is the first report using mediatorless SPEs (bare/unmodified) towards the sensing of sulfide. In addition, the electroanalytical efficacy of the SPEs is also explored towards the detection of sulfide within model aqueous solutions and real drinking water samples presenting good apparent recoveries, justifying the plausibility of this graphitic mediatorless screen-printed platform.

Tech Support

Section titled “Tech Support”

Original Source

Section titled “Original Source”

References

Section titled “References”
  1. 2012 - Flow injection amperometric detection of sulfide using using a prussian blue modified glassy carbon electrode [Crossref]
  2. 1993 - Determination of carbonyl sulfide and hydrogen sulfide species in natural waters using specialized collection procedures and gas chromatography with flame photometric detection [Crossref]
  3. 2008 - Sulfide and sulfate determination in water samples by means of hydrogen sulfide generation-inductively coupled plasma-atomic emission spectrometry [Crossref]
  4. 2015 - Antimony film screen-printed carbon electrode for stripping analysis of Cd(II), Pb(II), and Cu(II) in natural samples [Crossref]
  5. 2013 - Chemiluminiscent detection of enzimatically produced hydrogen sulfide: substrate hydrogen bonding influences selectivity for H2S over biological thiols [Crossref]
  6. 2000 - Analytical strategies for the detection of sulfide: a review [Crossref]
  7. 2012 - A review of sensor-based methods for monitoring hydrogen sulfide [Crossref]
  8. 2013 - Exploring the origins of the apparent “electrocatalytic” oxidation of kojic acid at graphene modified electrodes [Crossref]
  9. 2012 - The electrochemical performance of graphene modified electrodes: An analytical perspective [Crossref]
  10. 2013 - Forensic electrochemistry: Sensing the molecule of murder atropine [Crossref]

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