Study of carbon dioxide electrochemical reduction in flow cell system using copper modified boron-doped diamond

At a Glance

Metadata	Details
Publication Date	2020-01-01
Journal	E3S Web of Conferences
Authors	Salsabila Zahran Ilyasa, Prastika Krisma Jiwanti, Munawar Khalil, Yasuaki Einaga, Tribidasari A. Ivandini
Institutions	University of Indonesia, Airlangga University
Citations	4
Analysis	Full AI Review Included

Technical Documentation & Analysis: Copper-Modified BDD for CO₂ Reduction

This document analyzes the research on using copper-modified boron-doped diamond (Cu-BDD) electrodes in a flow cell system for CO₂ electrochemical reduction (CO₂RR). It highlights the technical achievements and connects the material requirements directly to 6CCVD’s advanced MPCVD diamond capabilities.

Executive Summary

The study successfully demonstrates the enhanced catalytic performance of Boron-Doped Diamond (BDD) electrodes modified with copper nanoparticles for CO₂ reduction, achieving high selectivity for formic acid (HCOOH) in a flow cell system.

Material Enhancement: BDD electrodes were modified via chronoamperometry to deposit copper nanoparticles, significantly improving the catalytic activity compared to bare BDD.
Optimal Configuration: The Cu-BDD 100s electrode, characterized by uniformly distributed Cu particles (~148 nm), was identified as the optimal configuration for CO₂RR.
System Design: A two-compartment PTFE flow cell was utilized to enhance CO₂ mass transport, which is critical for high-efficiency electrochemical processes.
Primary Product Selectivity: The flow cell system, combined with the Cu-BDD catalyst, selectively produced formic acid (HCOOH) as the main product.
Performance Metric: The optimized Cu-BDD electrode achieved a Faradaic Efficiency (FE) of 33.00% for formic acid, more than doubling the efficiency of the bare BDD electrode (14.69% FE).
Flow Cell Advantage: The use of the flow cell suppressed the formation of C₂/C₃ hydrocarbon products, demonstrating the importance of system engineering in product selectivity.

Technical Specifications

The following hard data points were extracted from the experimental results, focusing on the optimal Cu-BDD 100s electrode performance.

Parameter	Value	Unit	Context
Base Electrode Material	Boron-Doped Diamond (BDD)	N/A	Prepared on Si(100) via MPCVD
Working Electrode Area	9.62	cm²	Used in two-compartment PTFE flow cell
Optimal Cu Deposition Potential	-0.6	V (vs. Ag/AgCl)	Chronoamperometry technique
Optimal Cu Deposition Time	100	seconds	Yielded Cu-BDD 100s electrode
Average Cu Particle Size	~148	nm	Observed via SEM on Cu-BDD 100s
Applied Reduction Potential	-1.5	V (vs. Ag/AgCl)	Applied for 1 hour CO₂ reduction
CO₂/N₂ Flow Rate	200	sccm	Gas bubbling rate into catholyte
HCOOH Faradaic Efficiency (Cu-BDD)	33.00	%	Highest selectivity achieved
HCOOH Concentration (Cu-BDD)	11.33	mg/L	Concentration of main liquid product
H₂ Faradaic Efficiency (Cu-BDD)	21.25	%	Competing hydrogen evolution reaction
Cu Mass Percentage (Optimal)	0.83	%	Determined by EDS on Cu-BDD 100s

Key Methodologies

The following steps outline the preparation of the BDD electrodes and the subsequent CO₂ electrochemical reduction process.

BDD Substrate Growth: Boron-doped diamond films were prepared on Si(100) wafers using a Microwave Plasma-Assisted Chemical Vapor Deposition (MPCVD) system.
Copper Electrodeposition: Copper modification was performed using a chronoamperometric technique in a solution of 1 mM CuSO₄ in 0.1 M H₂SO₄.
Potential Application: A constant potential of -0.6 V (vs. Ag/AgCl) was applied to the BDD working electrode for varying durations (25s, 50s, 100s, 150s) to optimize Cu loading.
Electrode Characterization: Electrodes were analyzed using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX), and X-Ray Photoelectron Spectroscopy (XPS) to confirm Cu deposition and uniformity.
Flow Cell Setup: CO₂ reduction was carried out in a two-compartment PTFE flow cell separated by a Nafion membrane. The working electrode was Cu-BDD, with Ag/AgCl as the reference and Pt plate as the counter electrode.
Electrolysis Procedure: The catholyte was saturated first with N₂ (30 minutes) and then with CO₂ (15 minutes) at 200 sccm. Reduction was performed for 1 hour at -1.5 V.
Product Quantification: Liquid products (HCOOH) were analyzed using High-Performance Liquid Chromatography (HPLC), and gaseous products (CO, CH₄, H₂) were analyzed using Gas Chromatography (GC).

6CCVD Solutions & Capabilities

This research validates the critical role of high-quality Boron-Doped Diamond (BDD) substrates in advanced electrochemical applications like CO₂ reduction. 6CCVD is uniquely positioned to supply and enhance the materials required to replicate and scale this research.

Research Requirement	6CCVD Solution & Capability	Technical Advantage & Sales Driver
Applicable Materials: High-Quality BDD Substrates	Heavy Boron-Doped PCD/SCD Wafers. We supply MPCVD-grown BDD materials with controlled boron doping levels necessary for wide potential window electrochemistry and high stability.	Our BDD materials ensure low background current and superior chemical inertness, maximizing the efficiency of the Cu active sites. We offer both Polycrystalline (PCD) and Single Crystal (SCD) BDD options.
Electrode Dimensions: 9.62 cm² Working Area	Custom Dimensions & Precision Laser Cutting. 6CCVD manufactures PCD plates up to 125mm diameter. We provide precision laser cutting services to match exact flow cell geometries (e.g., 9.62 cm²) or custom shapes required for scale-up.	Engineers can specify exact dimensions, eliminating material waste and ensuring perfect integration into proprietary flow cell or reactor designs.
Surface Modification: Uniform Cu Nanoparticle Deposition	Integrated Metalization Services (Cu, Pt, Pd, Ti). While the paper used electrodeposition, 6CCVD offers advanced, high-uniformity metal deposition (e.g., sputtering or evaporation) of Cu, Pt, or Pd layers directly onto the BDD surface.	Achieve superior adhesion, purity, and thickness control of the catalytic layer, potentially leading to more stable and reproducible Faradaic Efficiencies than simple electrochemical methods.
Surface Finish: Requirement for uniform nucleation	Ultra-Low Roughness Polishing. Our standard polishing achieves Ra < 5 nm for inch-size PCD and Ra < 1 nm for SCD. A pristine, low-roughness surface is crucial for controlled, uniform nucleation of metal nanoparticles.	A smoother surface minimizes defects and ensures predictable electrodeposition kinetics, maximizing the density and uniformity of the catalytic Cu sites.
Engineering Support: Optimization for CO₂RR	In-House PhD Engineering Team. 6CCVD provides consultation on material selection, doping concentration, and surface termination (e.g., hydrogen vs. oxygen termination) to optimize BDD performance for specific CO₂RR products (e.g., HCOOH, CO, or C₂ species).	Leverage our expertise to accelerate your research timeline and ensure the diamond substrate is perfectly tailored for your specific electrochemical application.

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

View Original Abstract

High concentrations of CO2 in the atmosphere may cause climate and environmental changes. Therefore, various research has been extensively performed to reduce CO 2 by converting CO 2 directly into hydrocarbons. In this research, CO 2 electrochemical reduction was studied using boron-doped diamond (BDD) modified with copper nanoparticles to improve BDD electrodes’ catalytic properties. The deposition was performed by chronoamperometry technique at a potential of -0.6 V (vs. Ag/AgCl) and characterized using SEM, EDS, XPS, and cyclic voltammetry (CV). CO 2 electrochemical reduction on BDD and Cu-BDD was carried out at -1.5 V (vs. Ag/AgCl) for 60 minutes. The products were analyzed using HPLC and GC. The product was mainly formic acid with a concentration of 11.33 mg/L and 33% faradaic efficiency on a Cu-BDD electrode.

Tech Support

Original Source

DOI: https://doi.org/10.1051/e3sconf/202021103011