Boron-doped Diamond Electrode Research Articles

Application of Boron-doped Diamond Electrodes: Focusing on the Electrochemical Reduction of Carbon Dioxide

Application of Boron-doped Diamond Electrodes: Focusing on the Electrochemical Reduction of Carbon Dioxide

Toward abiotic sugar synthesis from CO2 electrolysis

Toward abiotic sugar synthesis from CO2 electrolysis

Electron Paramagnetic Resonance for the Detection of Electrochemically Generated Hydroxyl Radicals: Issues Associated with Electrochemical Oxidation of the Spin Trap.

For the detection of electrochemically produced hydroxyl radicals (HO·) from the oxidation of water on a boron-doped diamond (BDD) electrode, electron paramagnetic resonance spectroscopy (EPR) in combination with spin trap labels is a popular technique. Here, we show that quantification of the concentration of HO· from water oxidation via spin trap electrochemical (EC)-EPR is problematic. This is primarily due to the spin trap oxidizing at potentials less positive than water, resulting in the same spin trap-OH· adduct as formed from the solution reaction of OH· with the spin trap. We illustrate this through consideration of 5,5-dimethyl-1-pyrroline N-oxide (DMPO) as a spin trap for OH·. DMPO oxidation on a BDD electrode in an acidic aqueous solution occurs at a peak current potential of +1.90 V vs SCE; the current for water oxidation starts to rise rapidly at ca. +2.3 V vs SCE. EC-EPR spectra show signatures due to the spin trap adduct (DMPO-OH·) at potentials lower than that predicted thermodynamically (for water/HO·) and in the region for DMPO oxidation. Increasing the potential into the water oxidation region, surprisingly, shows a lower DMPO-OH· concentration than when the potential is in the DMPO oxidation region. This behavior is attributed to further oxidation of DMPO-OH·, production of fouling products on the electrode surface, and bubble formation. Radical scavengers (ethanol) and other spin traps, here N-tert-butyl-α-phenylnitrone, α-(4-pyridyl N-oxide)-N-tert-butylnitrone, and 2-methyl-2-nitrosopropane dimer, also show electrochemical oxidation signals less positive than that of water on a BDD electrode. Such behavior also complicates their use for the intended application.

Highly Sensitive Determination of Atropine in Pharmaceuticals, Biological Fluids and Beverage on Planar Electrochemical Cell with Working Boron-Doped Diamond Electrode

In the present paper, for the first time, a planar electrochemical cell formed of a novel screen-printed sensor with the working boron-doped diamond electrode (BDDE) was used for the voltammetric determination of alkaloid atropine (ATR). Different BDDE diameters of 1, 2 and 3 mm were used. ATR gives one irreversible oxidation peak at the potential of 1.5 V in the presence of 2 M HClO4. Two irreversible peaks of ATR oxidation at potentials 1.0 V and 1.2 V were obtained using Britton-Robinson buffer at pH 11. Differential pulse voltammetry (DPV) and square-wave voltammetry (SWV) were used to obtain calibration curves for ATR on BDDE. The use of cells with various BDDE diameters enables an expansion of the range of linear concentration. The limit of detection (LOD) reaches the lowest value of 0.08 μМ using DPV on BDDE with the diameter of 3 mm. Using the working electrode with the diameter of 1 mm it is possible to determine 4.1 μМ ATR. ATR can be determined in drugs (without multistage dilution and separation) and biological fluids using planar cells. The method has also been approved to determine ATR at the lethal dose level and below in Cola. One drop of the beverage is enough for this analysis. The developed methods were validated according to the criteria such as linearity, limits of detection and quantification, accuracy, precision, stability, and selectivity. The presented analysis protocols are rapid, inexpensive, portable, and relevant.

Electro-conversion of cumene into acetophenone using boron-doped diamond electrodes.

A straightforward electro-conversion of cumene into acetophenone has been reported using boron-doped diamond (BDD) electrodes. This particular conversion is driven by the addition reaction of a cathodically generated hydroperoxide anion to an anodically generated cumyl cation, where the BDD’s wide potential window enables the direct anodic oxidation of cumene into the cumyl cation. Since electricity is directly employed as the oxidizing and reducing reagents, the present protocol is easy to use, suitable for scale-up, and inherently safe.

Electrochemical detection of triamterene in human urine using boron-doped diamond electrodes

Urine is one of the most used biological fluids for screening drug delivery and the resultant metabolites. In sports, the use of diuretics such as triamterene is considered a violation of anti-doping rules and is stipulated to be present at less than 79 nM in urine by the World Anti-Doping Agency (WADA). It is therefore important to develop effective rapid and low-cost tests for this diuretic. Here we apply electrochemical analysis using boron-doped diamond (BDD) electrodes, which have superior properties such as low background current, a wide potential window, and high resistance to deactivation. Since real urine samples show clear oxidation current peaks in the potential range more positive than 0.5 V (vs. Ag/AgCl) due to the presence of bio-components such as protein, uric acid, and ascorbic acid, to detect triamterene effectively, the electrochemical protocol was optimized towards a potential range where the other components have limited effect. Our results show that reduced triamterene exhibits an oxidation peak at 0.1 V (vs. Ag/AgCl) in 0.1 M phosphate buffer (PB) and at 0.2 V (vs. Ag/AgCl) in pooled human urine. The peak current value increased according to the triamterene concentration. The limit of detection (LOD) was 3.15 nM in the PB and 7.80 nM in pooled human urine. Finally, triamterene detection was attempted in individual urine samples. Triamterene was electrochemically detectable in individual urine samples, excluding urine samples containing an excess amount of ascorbic acid. The limit of detection (LOD) in individual urine samples was determined to be 20.8 nM.

Combination of granular activated carbon adsorption and electrochemical oxidation processes in methanol medium for benzene removal

• Benzene can be mineralized electrochemically from methanol electrolytes. • Better efficiency of the combined GAC/electrolytic process for removal of benzene. • Formation of anisole opens the possibility of electro-refinery as treatment technology. • Adsorption/electrolysis doesn't reach initially expected efficiency but overcomes water electrolysis. One of the impacts caused by the increase in anthropogenic activities, related to the accelerated urbanization and industrialization, is the increase in emissions of volatile organic compounds (VOC). This type of air pollution has become a matter of great concern nowadays, because of its harmfulness to the environment and human health. Adsorption technologies are one of the most promising methods for decontaminating VOCs from the air because they are simple, inexpensive, and energy efficient. On the other hand, electrochemical treatments have been extensively and successfully studied for water treatment. The combination of an adsorption step followed by an electrochemical treatment, with the regeneration of the adsorbent material, can be an interesting alternative, mainly to overcome the limitations of the treatment of diluted solutions. In this work, the removal of benzene from diluted water solutions were evaluated using a combination of three processes: adsorption, desorption with methanol and electrochemical oxidation with boron-doped diamond electrode (BDD) of the high concentrated solution obtained. This technology is suitable for the recovery of the adsorbent material (granular activated carbon), which can be reused after drying. Two possible concurrent ways to remove benzene from methanol solutions by electrochemical oxidation were found: (1) mineralization and (2) conversion to anisole, a solvent of commercial interest used in the cosmetics industry. The performance of electrochemical treatment for benzene removal from methanol solution was not so different than that in water, but the energy consumption was greater. However, the production of high added-value products is a very interesting finding that will advance the development of more sustainable treatment processes.

Fabrication of Boron-Doped Diamond Film Electrode for Detecting Trace Lead Content in Drinking Water.

This work aimed to fabricate a boron-doped diamond film electrode for detecting trace amounts of lead in drinking water so as to safeguard it for the public. Available detectors suffer from high costs and complex analytical processes, and commonly used electrodes for electrochemical detectors are subject to a short life, poor stability, and secondary pollution during usage. In this work, a boron-doped diamond (BDD) electrode was prepared on a porous titanium substrate, and the microstructure and electrochemical properties of the BDD electrode were systematically studied. Moreover, the stripping parameters were optimized to obtain a better signal response and determine the detection index. As a result, diamond particles were closely arranged on the surface of the BDD electrode with good phase quality. The electrode showed high electrochemical activity, specific surface area, and low charge transfer resistance, which can accelerate the stripping reaction process of Pb2+. The BDD electrode presented a low detection limit of 2.62 ppb for Pb2+ under an optimized parameter set with an enrichment time of 150 s and a scanning frequency of 50 Hz. The BDD electrode also has good anti-interference ability. The designed BDD electrode is expected to offer a reliable solution for the dilemma of the availability of metal electrodes and exhibits a good application prospect in the trace monitoring of Pb2+ content in drinking water.

Using Electrochemical Oxidation to Remove PFAS in Simulated Investigation-Derived Waste (IDW): Laboratory and Pilot-Scale Experiments

Repeated use of aqueous firefighting foams at military aircraft training centers has contaminated groundwater with per and polyfluorinated alkyl substances (PFAS). To delineate the extent of PFAS contamination, numerous site investigations have occurred, which have generated large quantities of investigation-derived wastes (IDW). The commonly used treatment of incinerating PFAS-tainted IDW is costly, and was recently suspended by the Department of Defense. Given long-term IDW storage in warehouses is not sustainable, our objective was to use electrochemical oxidation to degrade PFAS in contaminated water and then scale the technology toward IDW treatment. This was accomplished by conducting a series of laboratory and pilot-scale experiments that electrochemically oxidized PFAS using direct current with boron-doped diamond (BDD) electrodes. To improve destruction efficiency, and understand factors influencing degradation rates, we quantified the treatment effects of current density, pH, electrolyte and PFAS chain length. By using 14C-labeled perfluorooctanoic acid (PFOA) and tracking temporal changes in both 14C-activity and fluoride concentrations, we showed that oxidation of the carboxylic head (-14COOH → 14CO2) was possible and up to 60% of the bonded fluorine was released into solution. We also reported the efficacy of a low-cost, 3D printed, four-electrode BDD reactor that was used to treat 189 L of PFOA and PFOS-contaminated water (Co ≤ 10 µg L−1). Temporal monitoring of PFAS with LC/MS/MS in this pilot study showed that PFOS concentrations decreased from 9.62 µg L−1 to non-detectable (<0.05 µg L−1) while PFOA dropped from a concentration of 8.16 to 0.114 µg L−1. Efforts to improve reaction kinetics are ongoing, but current laboratory and pilot-scale results support electrochemical oxidation with BDD electrodes as a potential treatment for PFAS-tainted IDW.

Voltammetric determination of antipsychotic drug flupentixol HCl in human serum at a boron-doped diamond electrode

This study aims to offer a voltammetric method for determining the antipsychotic drug flupentixol from serum samples. According to pH and scan rate studies, the oxidation behavior of flupentixol at boron-doped diamond electrode was found as irreversible and diffusion-controlled. In order to determine flupentixol from bulk form and serum samples, differential pulse voltammetry was preferred as the working method because of the repeatability. Linear responses were obtained in the range of 6.0×10-7 – 8.0×10-6 M and 8.0×10-7 – 1.0×10-5 M for bulk form and serum samples in pH 2.0 Britton-Robinson buffer solution, with detection limit values of 1.09×10-7 M and 1.08×10-7 M, respectively. Required validation parameters were also studied and according to recovery from serum samples (99.91 %) and precision studies, it can be said that developed method was accurate and precise.

Construction of flexible fiber-shaped boron-doped diamond film and its supercapacitor application

Flexible fiber-shaped supercapacitors (FSSCs) are promising candidates as electrode materials for the development of deformable electronic devices. Although tremendous efforts have been focused on the preparation of flexible electrode materials, traditional FSSCs materials face problems of inferior stability and complicated processes. Boron-doped diamond (BDD) holds promise as a FSSC electrode, owing to its well-established preparation process, strong acid and alkali corrosion resistance, environmentally and skin-friendly characteristics. Here, we reported a novel strategy for the construction of BDD-based FSSCs by growing a BDD film on a flexible tantalum (Ta) fiber substrate through hot filament chemical vapor deposition technique. Results showed that the BDD fiber film featured 10 folds improvement in specific capacitance than a planar BDD electrode. A symmetric supercapacitor device was assembled using the BDD fiber electrode and achieved an energy density of 25.6 mJ cm−2 at a power density of 0.6 mW cm−2, and a desirable stability with higher capacitance retention of 93.5% after 20,000 cycles. Furthermore, the symmetric BDD fiber device exhibited satisfactory bendability with high specific capacitance retention under various bending deformations. The findings in this research work hold promise for the fabrication of high performance flexible FSSCs.

PbO2 modified BDD electrode by dicationic ionic liquids assisted electrodeposition for efficient electrocatalytic degradation of pesticide wastewater.

Pesticide wastewater is difficult to treat, and it is necessary to develop a new anode material electrochemical oxidation to efficiently degrade pesticide wastewater. DIL-PbO2-Ti/BDD electrodes with better electrocatalytic oxidation performance were obtained by using dicationic ionic liquid (DIL) for assisted electrodeposition of PbO2 modified boron-doped diamond (BDD) electrodes. At a current density of 100 mA cm-2 and a temperature of 25 °C, the DIL-PbO2-Ti/BDD electrode was used as anode and titanium plate as cathode. The electrochemical window and oxygen evolution potential (OEP) of the DIL-PbO2-Ti/BDD electrode obtained by CV testing at a scan rate of 50 mV s-1 in 1 M H2SO4 were 4.12 and 3.29 V, respectively. Under the conditions of current density of 100 mA cm-2, 25 °C, pH 12, salt content of 8%, chemical oxygen demand (COD) of 24,280.98 mg L-1, and total nitrogen (TN) content of 5268 mg L-1, after electrification for 12 h, the removal efficiency of COD and TN reached 64.88 and 67.77%, respectively, indicating that the DIL-PbO2-Ti/BDD electrode has excellent electrocatalytic performance. In order to further understand the mechanism of electrochemical degradation of pesticide wastewater, HPLC-MS was used to detect the intermediates in the degradation process, and the possible degradation pathways were proposed in turn.

A nanoporous diamond particle microelectrode and its surface modification

Boron doped diamond electrode (BDDE) with dimensions of tens of or hundreds of μm has received widespread attention for electrochemical and biological applications because of exceptional features such as wide potential window for water stability, excellent electrochemical/chemical stability, and superior antifouling properties. This work reported a feasible way to fabricate a single nanoporous BDD particle microelectrode (sDPME) using a commercial single-crystal BDD particle (cBDD) as the substrate. The nanoporous surface of cBDD (pcBDD) was formed via thermal catalytic treatment with nickel as the catalyst, followed by further electrodeposition of gold nanoparticles (Au NPs) to fill the nanopores, increasing its electrocatalytic performance. As a comparison, the heavily-doped polycrystalline BDD film was deposited on cBDD via hot-filament chemical vapor deposition, increasing its electrical surface conductivity, followed by the similar thermal etching to form the nanoporous surface (prBDD) as well as Au NPs modification. We gradually characterized surface modification of cBDD using scanning electron microscopy, Raman, energy dispersive spectroscopy and various electrochemical techniques. The results demonstrated that among six sDPMEs, the Au NPs-modified nanoporous sDPMEs (Au/prBDD) have one order of magnitude higher heterogeneous electron transfer kinetic constant than the cBDD. This difference was attributed to synergistic effects of the improved electrical conductivity (with a higher doping level of few 1020 cm−3 versus 1018 cm−3), the improved capability for electron transfer (with lower charge transfer resistance of 1.3 kΩ versus 8.6 kΩ) as well as the increased electrochemically active surface area (1.12 mm2 versus 0.34 mm2).

Electrochemical Sensor of Levofloxacin on Boron-Doped Diamond Electrode Decorated by Nickel Nanoparticles

Levofloxacin (LEV) was known as one of the fluoroquinolone antibiotics that widely used as an antibacterial agent. Monitoring of LEV is important due to its negative side effect on humans. The determination of LEV was studied for the first time on nickel modified on a boron-doped diamond (NiBDD) electrode using the square wave voltammetry (SWV) method to improve the catalytic and sensitivity of the sensor. The response was linear in the range of 30–100 mM LEV. LEV sensor on NiBDD was found to be selective in the presence of urea, glucose, and ascorbic acid interferences. Good reproducibility with % a relative standard deviation of 1.45% (n = 10) was achieved. Therefore, the NiBDD electrode could be potentially applied for the real detection method of LEV.

Removal of ofloxacin from wastewater by chloride electrolyte electro-oxidation: Analysis of the role of active chlorine and operating costs

Electro-oxidation (EO) has received increasing attention as an efficient and green method for removing pollutants from wastewater. Chloride anions (Cl−), which commonly exist in wastewater, can act as an electrolyte for the EO process. However, the role of reactive chlorine species (RCS) generated near electrodes is often underestimated. In this study, we generated hydroxyl radicals (OH) and RCS in a boron-doped diamond (BDD) electrode system and investigated its degradation mechanism for ofloxacin (OFX) removal. The findings suggested that OFX degradation was dominated by OH existing near the anode in solution, with RCS playing a supporting role. Based on the produced intermediates, we proposed an OFX decomposition pathway. The biological toxicities of the intermediates were evaluated through the ECOSAR and T.E.S.T. procedure. Nearly half of the intermediates are less toxic than the parent compound. After optimizing the operating parameters by the response surface methodology, 20 mg/L OFX was almost completely degraded after 10 min of reaction in 1.45 g/L NaCl with a current density (j) of 18 mA/cm2, and the total organic carbon was decreased by 30.55 %. The energy consumption and current efficiency were 0.648 kW·h/gTOC and 8.65 %, respectively. Comparing the operating costs of the proposed and other EO methods, our method emerged as a viable new treatment scheme for similar polluted wastewaters. This study aims to comprehensively understand the potential application value of BDD electrodes in the treatment of Cl− containing organic wastewater.

Efficient electrochemical degradation of X-GN dye wastewater using porous boron-doped diamond electrode

Surface porous Ti substrates were obtained by electrodeposition–hot melt–alkali etching. Porous-Ti/BDD and flat-Ti/BDD electrodes were prepared for comparative study. The results of SEM, Raman, and XRD analyses show that the BDD films of these two electrodes had good uniformity and stable quality. The electrochemical window (EW) and electrochemical-active surface area (EASA) of the porous-Ti/BDD electrode is as high as 4.21 V and 22.78 cm2 (11.39 cm2/cm2), respectively. Furthermore, the electrochemical catalytic performance and degradation mechanism of porous-Ti/BDD electrode as the anode were studied by the electrolysis of Active Orange dye X-GN (X-GN), and the optimal electrochemical degradation operating parameters were obtained. The results show that when the degradation time was 50 min, the X-GN was completely decolorized. The TOC removal rate reached 69.24%, and the energy consumption was 5.62 kWh m−3. The contribution rate of •OH and SO4•− was calculated to be 91.40% and 1.26% by radical quenching experiments, respectively, indicating that the active substances in the degradation system were mainly •OH and SO4•−. The high specific surface characteristics of porous-Ti/BDD electrode enhanced its electrochemical oxidation advantages, and it showed a high degradation efficiency and low energy consumption for the treatment of X-GN simulated wastewater.

Recent advances on boron doped diamond (BDD) electrode as cathode in organic and inorganic preparative electrotransformations

Although anodic oxidation reactions mediated by boron-doped diamond (BDD) electrodes have been broadly studied, research on cathodic conversion remains still scarce despite the favorable characteristics of this electrode for such application. A detailed survey of the recent literature about processes in which boron-doped diamond electrode has been employed in cathodic reactions is presented, including inorganic species (O2, CO2, nitrate, metaborate) and organic compounds (carbonyl, nitro groups and halogenated compounds).

Antimony-doped tin dioxide ceramics used as standalone membrane electrodes in electrofiltration reactors enhance the oxidation of organic micropollutants

In the present work, microporous ceramics made of antimony-doped tin dioxide produced using a facile synthesis procedure were evaluated during the degradation of norfloxacin in a novel electrofiltration process. The antimony-doped tin dioxide ceramics were used as standalone electrodes accomplishing a dual function: as anodes and microfiltration membranes. The simultaneous generation of hydroxyl radicals and permeation of the electrolyte through the ceramic electrodes favors the effective utilization of their high active area in the degradation of organic compounds. The progress of the electrofiltration process was compared with that of a conventional flow electrolysis reactor using the ceramic electrodes and boron-doped diamond. By changing from a conventional flow reactor to an electrofiltration configuration, the effective utilization of the generated hydroxyl radicals is evidenced by the delayed transition from electrochemical-to mass transfer-controlled degradation rates. Evaluation of intermediate and by-product concentrations confirms the formation of acetate ions as a prior stage in the mineralization pathway using both types of electrodes. After 4 h of electrolysis, norfloxacin degradation rates of 98.3% and mineralization degrees of 82% were attained using the antimony-doped tin dioxide anodes at the highest permeate flow of 60 mL min −1 , approaching the outstanding performance of commercial boron-doped diamond electrodes. - Standalone Sb-doped SnO2 electrodes oxidize organic micropollutants - Microporous Sb-doped SnO2 plays a dual role as a membrane and as an electrode - Electrofiltration improves the effective use of • OH radicals in NOR oxidation. - Electrofiltration increases removal and mineralization of NOR - NOR removal degrees close to those achieved with BDD are obtained.

Enhanced susceptibility of SARS-CoV-2 spike RBD protein assay targeted by cellular receptors ACE2 and CD147: Multivariate data analysis of multisine impedimetric response.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) enters the cells through the binding of spike protein to the host cell surface-expressing angiotensin-converting enzyme 2 (ACE2) or by endocytosis mediated by extracellular matrix metalloproteinase inducer (CD147). We present extended statistical studies of the multisine dynamic electrochemical impedance spectroscopy (DEIS) revealing interactions between Spike RBD and cellular receptors ACE2 and CD147, and a reference anti-RBD antibody (IgG2B) based on a functionalised boron-doped diamond (BDD) electrode. The DEIS was supported by a multivariate data analysis of a SARS-CoV-2 Spike RBD assay and cross-correlated with the atomic-level information revealed by molecular dynamics simulations. This approach allowed us to study and detect subtle changes in the electrical properties responsible for the susceptibility of cellular receptors to SARS-CoV-2, revealing their interactions. Changes in electrical homogeneity in the function of the RBD concentration led to the conclusion that the ACE2 receptor delivers the most homogeneous surface, delivered by the high electrostatic potential of the relevant docking regions. For higher RBD concentrations, the differences in electrical homogeneity between electrodes with different receptors vanish. Collectively, this study reveals interdependent virus entry pathways involving separately ACE2, CD147, and spike protein, as assessed using a biosensing platform for the rapid screening of cellular interactions (i.e. testing various mutations of SARS-CoV-2 or screening of therapeutic drugs).

Inconsistency of BDD reactivity assessed by ferri/ferro-cyanide redox system and electrocatalytic degradation capability

Ferri/ferro-cyanide ([Fe(CN)6]3−/4−) redox couple has been extensively used as a benchmark to assess electrocatalytic degradation capability of boron-doped diamond (BDD) electrodes. However, the [Fe(CN)6]3−/4− is far more sensitive to the surface terminal groups of BDD surface than the other factors (e.g. surface morphology and electrode configuration) that are closely related to electrocatalytic degradation properties. Thus, inconsistency exists while correlating the degradation properties of BDD with electrochemical properties determined from ferri/ferro-cyanide redox couple. Herein, an exemplar pollutant, reactive blue 19 (RB-19), was electrochemically degraded using various terminated BDD electrodes, including hydrogen-terminated (H-BDD), oxygen-terminated (O-BDD) and porous oxygen-terminated BDDs (OE-BDD), obtained via cathodic and anodic polarization as well as oxygen plasma etching, respectively. Surprisingly, OE-BDD with the lower heterogeneous electron transfer rate constant for [Fe(CN)6]3−/4− showed a better electrocatalytic degradation capability toward RB-19, indicating the inconsistency for qualitatively evaluating degradation properties according to the kinetic parameters extracted from [Fe(CN)6]3−/4− redox system.