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Copper-nickel-modified Boron-doped Diamond Electrode for CO2 Electrochemical Reduction Application - A Preliminary Study

MetadataDetails
Publication Date2019-12-20
JournalMakara Journal of Science
AuthorsPrastika Krisma Jiwanti, Rani Puspitasar Aritonang, Imam Abdullah, Yasuaki Einaga, Tribidasari A. Ivandini
InstitutionsUniversity of Indonesia, Airlangga University
Citations18
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Copper-Nickel-Modified Boron-Doped Diamond Electrodes for CO₂ER: 6CCVD Technical Documentation

Section titled “Copper-Nickel-Modified Boron-Doped Diamond Electrodes for CO₂ER: 6CCVD Technical Documentation”

This document analyzes the fabrication and performance of Copper-Nickel-modified Boron-Doped Diamond (CuNi-BDD) electrodes for CO₂ Electrochemical Reduction (CO₂ER). This research confirms the superior stability and catalytic versatility of tailored MPCVD BDD films for advanced electrochemical applications.


The following points summarize the core technical achievements and commercial potential of the research utilizing BDD films for CO₂ reduction:

  • Advanced CO₂ER Catalysis: Demonstrated the successful use of bimetallic (CuNi) modification on Boron-Doped Diamond (BDD) electrodes to shift CO₂ER product distribution away from undesirable HCOOH.
  • Novel Product Generation: The CuNi-BDD configuration successfully produced valuable C₁ compounds, including methanol, methane, and CO, which are rarely observed with high yield on unmodified BDD electrodes.
  • BDD Substrate Integrity: The modified BDD electrode maintained its critical spÂł carbon bonding and structural stability, confirmed by Raman spectroscopy, even after high-temperature Rapid Thermal Annealing (RTA) at 700 °C.
  • Fabrication Methodology: A reliable, two-step modification process—combining wet chemical seeding with subsequent electrodeposition—was utilized to ensure strong metal adhesion and prevent particle detachment during electrolysis.
  • Overpotential Management: BDD’s inherent wide potential window was leveraged to suppress the competing Hydrogen Evolution Reaction (HER), making it an ideal platform for customizing CO₂ER selectivity through surface modification.
  • Scalable Materials: The foundation of the research—high-quality BDD films deposited via Microwave Plasma-Assisted Chemical Vapor Deposition (MPCVD)—is a core specialization of 6CCVD, facilitating immediate replication and scale-up.

Key operational parameters and material characteristics extracted from the experimental data:

ParameterValueUnitContext
BDD Deposition MethodMPCVDN/AFilms deposited on Si (111) wafers.
Metalization MethodWet Chemical Seeding + ElectrodepositionN/ABimetallic Cu/Ni modification.
RTA Stabilization Temperature700°CApplied for stability improvement.
RTA Duration5minConducted under N₂ atmosphere.
Electrodeposition Potential-1.2VApplied for 15 minutes.
Cu Content (EDS)0.11%Percentage content on BDD surface.
Ni Content (EDS)0.14%Percentage content on BDD surface.
Electrolyte System0.1 M NaCl / 0.1 M Na₂SO₄MCatholyte/Anolyte, separated by Nafion membrane.
Electrolysis Potentials Tested-1.2, -1.5, -1.7VPotentials measured vs. Ag/AgCl reference electrode.
Highest Total Current Density (Ni-BDD w/o RTA)10.24mA/cmÂČMeasured at -1.2 V (Indicates high potential for H₂ side reaction).
CuNi-BDD Current Density (RTA)0.42mA/cmÂČMeasured at -1.7 V (RTA reduces initial current density, requiring activation).
Key BDD Structure Peaks1332 and 1220cm-1spÂł Carbon bonding (1332) and B-B bond (1220) peaks confirmed integrity.

The CuNi-BDD electrode was fabricated using a specialized multi-step process focused on maximizing stability and ensuring strong metallic adhesion:

  1. BDD Substrate Preparation: Highly conductive BDD films were deposited on Si (111) wafers using standard Microwave Plasma-Assisted Chemical Vapor Deposition (MPCVD).
  2. Wet Chemical Seeding (Stabilization Layer):
    • A 1 M NaBH₄ solution in 0.1 M NaOH was dropped onto the BDD surface.
    • This was immediately followed by dropping 400 ”L of metal precursor solution (1 mM Cu(SO₄) and 1 mM Ni(NO₃)₂).
    • The bimetallic precursor ratio was set at 3:1 v/v (Ni:Cu).
  3. Drying and Rinsing: The seeded electrode was dried for 24 hours at room temperature and pressure, rinsed with ultrapure water, and dried under N₂ gas. This seeding process was repeated three times.
  4. Electrodeposition: Metal deposition was performed electrochemically for 15 minutes at a constant potential of -1.2 V in the 1 mM metal precursor solution to increase metal loading.
  5. Rapid Thermal Annealing (RTA): The electrode was stabilized by RTA treatment at 700 °C for 5 minutes in an inert N₂ atmosphere to improve mechanical stability.
  6. Electrochemical Activation: The RTA-passivated electrode was reactivated using several cycles of cyclic voltammetry (CV), serving as an electrochemical polishing technique.
  7. CO₂ER Testing: Electrolysis was conducted for 1 hour using a three-electrode cell configuration (Modified BDD as Working Electrode, Pt spiral as Counter Electrode, Ag/AgCl as Reference Electrode) with CO₂ bubbling at 100 sccm.

This research validates the critical role of high-quality, custom-engineered BDD substrates in developing next-generation electrochemical catalysts. 6CCVD is uniquely positioned to support the replication and advancement of this CO₂ER technology by providing tailored diamond materials and modification services.

To replicate or extend this research, 6CCVD recommends materials optimized for high-conductivity electrochemical applications:

  • Heavy Boron-Doped Polycrystalline Diamond (BDD-PCD): Essential for high current density applications like CO₂ER. 6CCVD offers BDD films with custom doping levels and thicknesses (0.1”m to 500”m) deposited on various substrates, ensuring low resistance and maximizing Faradaic efficiency.
  • High Purity CVD Diamond Substrates: For researchers requiring a robust platform for subsequent metal modification, 6CCVD provides PCD wafers up to 125mm in diameter, enabling seamless scale-up from lab-bench testing to larger prototypes.

The experimental approach utilized in the research—precise metal deposition and high-temperature thermal treatment—aligns perfectly with 6CCVD’s specialized fabrication capabilities:

  • Integrated Metalization Services: 6CCVD offers in-house deposition of metals utilized in advanced electrocatalysis (including Cu, Ni, Ti, W, Pt, Au, and Pd). We can provide electrodes pre-seeded or fully coated with complex bimetallic or ternary layers, ensuring superior stability compared to post-process modification.
  • Precision Manufacturing & Dimensions: The research requires custom electrode sizes for cell integration. 6CCVD provides custom laser cutting and shaping services, delivering wafers and plates in any required dimension (up to 125mm) with extreme precision.
  • Ultra-High Polishing: For applications requiring the lowest possible background current or specific surface energetics, 6CCVD can deliver SCD surfaces with an atomic-scale finish (Ra < 1nm) and inch-size PCD polished to Ra < 5nm.

The challenges noted in the paper (e.g., incomplete RTA activation and optimizing metal composition) require specialized expertise.

  • 6CCVD’s in-house PhD-level engineering team specializes in MPCVD recipe development and post-deposition processing. We can assist researchers in optimizing doping homogeneity, film thickness, and subsequent thermal treatments (like RTA) to ensure complete activation and stability for CO₂ER projects.
  • We offer consultation on material selection, specifically targeting the ideal balance between BDD doping concentration (conductivity) and surface roughness (catalyst support area) for specific metal-modified electrocatalysis projects.

Ensure your next advanced electrochemical project begins with the highest quality, customized diamond material. For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly. We offer global shipping (DDU default, DDP available) for seamless delivery.

View Original Abstract

CO2 electrochemical reduction (CO2ER) activity is known to be influenced by electrode materials. In this study, we report the fabrication of a copper-nickel-modified boron-doped diamond (CuNi-BDD) electrode using wet chemical seeding and electrodeposition. Annealing was performed to improve the stability of the modified electrode during elec-trolysis. Characterization of the modified BDD electrodes shows successful deposition without damage to the surface of the BDD support material. CO2ER was conducted with the CuNi-BDD electrode, which produces various important products including methanol, formic acid, CO, and CH4. Additionally, a different applied potential affected the product distribution. CO2ER was also conducted on the surfaces of Cu-BDD and Ni-BDD electrodes for comparison.