Bi Film Electrode Research Articles

New perspective on the electrodeposition of Pb, Cd and Zn in electrode modified with bismuth film: A theoretical–experimental approach

Understanding electrode-analyte interactions at the atomic level is vital for improving analytical techniques, yet the complexity of these interactions poses a significant challenge for refinement.In this study, we investigate the detection of transition metals using Bi film electrodes, combining Density Functional Theory (DFT) simulations with experimental Anodic Stripping Voltammetry (ASV). Our experiments focus on the electrodeposition and detection of Zn2+, Cd2+, and Pb2+using Bi-modified carbon electrodes. The ASV experiments reveal a notably higher sensitivity for Pb2+detection compared to Zn2+and Cd2+, whether evaluated individually or simultaneously. DFT calculations demonstrate that the higher adsorption energy of Pb on the Bi surface promotes a uniform distribution of Pb atoms, resulting in a homogeneous phase. Conversely, Cd and Zn tend to present lower adsorption energies and form metallic clusters, leading to phase segregation. The correlation between theoretical and experimental data suggests that a more uniform deposition of Pb on the electrode surface facilitates a regular sweep in the redissolution step, achieving a detection limit as low as 0.062 nM for Pb. This synergistic approach not only enhances our understanding of electrode-analyte interactions but also provides valuable insights for optimizing electrode materials and detection methodologies in analytical chemistry.

Amorphous germanium-crystalline bismuth films as a promising anode for magnesium-ion batteries

Magnesium-ion batteries (MIBs) are promising alternatives to lithium-ion batteries due to their safety and high theoretical specific capacity, and the abundance of magnesium reserves. However, their anodes and electrolytes severely restrict the development of MIBs, so alloy-type anodes provide an effective strategy to circumvent the surface passivation issue encountered with Mg metal in conventional electrolytes. Theoretically, a germanium anode can deliver a high specific capacity of 1476 mAh g−1, but hitherto, no experimental reports have described Ge in MIBs. Herein, we experimentally verified that Ge could reversibly react with Mg2+ ions through the design of dual-phase Ge–Bi film electrodes fabricated by magnetron co-sputtering. Notably, a Ge57Bi43 electrode delivered a high specific capacity of 847.5 mAh g−1, owing to the joint alloying reactions of Ge and Bi with Mg, which was much higher than the specific capacity of Bi (around 385 mAh g−1). Moreover, the Ge–Bi anode showed excellent rate performance, good cycling stability, and superior compatibility with conventional electrolytes such as Mg(TFSI)2. More importantly, the Mg storage mechanism of the Ge–Bi anode was unveiled by operando X-ray diffraction, and density functional theory calculations rationalized that the introduction of Bi to form Ge–Bi evidently decreased the defect formation energy and effectively boosted the electrochemical reactivity of Ge with Mg.

Electrocatalytic CO2 reduction reaction over group 15 bismuth and antimony film electrodes: What makes difference?

Electrocatalytic CO2 reduction reaction (EC CO2 RR) activities and products are known to be highly dependent on the nature of electrode materials. Herein, Bi and Sb (in group 15 with n-1d10ns2np3) electrodes were chosen and evaluated for EC CO2 RR under various conditions of different applied potentials, electrolytes, concentration, and UV light. Major products were observed to be formate and H2, and minor products included CO. Bi film electrode showed high Faradaic efficiency (FE) of ~94% and the selectivity of 95% for formate. Overlayer vanadium on Bi further enhanced the FE of formate. However, Sb film exhibited much higher FE of H2 than that of formate. UV light was observed to promote formate and CO productions. The FEs of formate and H2 were discussed with exposed crystal facets and density of states near the Fermi level. The very unique detailed study provides valuable information on the development of Bi and Sb-based electrodes for EC CO2 RR of producing value-added carbon products.

Self-driving CO2-to-formate electro-conversion on Bi film electrode in novel microbial reverse-electrodialysis CO2 reduction cell

Sustainable energy recovery from microbial electrochemical system provided a promising way for the electrochemical reduction of CO2 into value-added products, which potentially tackled the problems regarding to the higher electrical energy input. Herein, a microbial reverse-electrodialysis CO2 reduction cell (MRECC) was developed to achieve self-driving CO2-to-formate conversion by extracting the energy from salinity gradient and wastewater simultaneously. Results confirmed that assembling 11 cell pairs in reverse electrodialysis (RED) stack of MERCC could meet the potential requirement of Bi film cathode for driving CO2 reduction. The cell pairs, flow rate of the salt solution (sodium chloride) and the external resistance showed obvious effects on the MRECC performance. Under the optimal condition, the maximum formate concentration of 185.4 ± 6.1 mg L−1 and faradaic efficiency of 88.9 ± 3.2% were yielded with anodic COD removal up to 87.0 ± 4.3%. Energy efficiency indicated nearly 5.8% of extracted energy from salinity gradient and wastewater had been utilized for CO2-to-formate conversion. Overall, MRECC exhibited a promising platform for CO2 reduction and value-added chemicals production by using sustainable energy from wastewater.

Electroreduction of CO2 to formate with excellent selectivity and stability on nano-dendrite Bi film electrode

Electroreduction of CO2 into value-added fuels has been considered as a promising technology to mitigate the CO2-invoked greenhouse effect. However, the poorer selectivity and lower stability of electrocatalysts still impede its development. In this work, we prepared a nano-dendrite Bi film electrode by simple one-step electrodeposition method. The Bi (1200) (deposition time of 1200s) exhibited a superior catalytic activity in a wide potential towards CO2-to-formate conversion and acquired the maximum faradaic efficiency (FEformate) of 97.5 % at –1.5 V vs Ag/AgCl. More encouragingly, it showed an excellent stability as the FEformate maintained ∼ 90 % over 108 h of electrolysis which outperformed most of the reported Bi-based electrodes. The notable performance was mainly attributed to the thorn-like structure which afforded massive active sites. Meantime, Bi-O structure on oxide-derived Bi was beneficial for CO2 adsorption and activation with accelerated interfacial charge transfer process. Moreover, the well-preserved electrode morphology and Bi-O component enabled its longer stable service life. This result implied Bi film electrode would be a promising candidate for efficient CO2 electroreduction.

Bismuth-tin-film electrodes for Zn(II), Cd(II), and Pb(II) trace analysis

The focus of this work is the novel development and validation of different in situ formed Bi-Sn-film glassy carbon electrodes (BiSnFEs) with changed Bi(III):Sn(II) mass concentration ratios (2:8, 4:6, 6:4, 8:2). These electrodes were formed from solutions with 0.5 mg/L and 1.0 mg/L total Bi(III) and Sn(II) mass concentrations – therefore, eight new electrodes were designed. BiSnFEs were compared with pure Bi-film electrodes (BiFEs) and Sn-film electrodes (SnFEs). It was shown that all electrodes tested demonstrated a high degree of selectivity for Zn(II), Cd(II), and Pb(II) determination, with clearly separated stripping peaks. The widest linear concentration range for Zn(II) determination was obtained at 19.6–413.9 μg/L using an electrode with a Bi(III):Sn(II) ratio of 0.6:0.4 at 0.5 mg/L total mass concentration. For Cd(II) and Pb(II), the widest linear concentration range was measured using pure SnFE at 0.5 mg/L. Moreover, different BiSnFEs significantly increased the method's sensitivity for Zn(II), Cd(II), and Pb(II) determination compared with pure BiFEs and SnFEs. The lowest LOD values were measured using pure BiFEs; however, the LOD values were also relatively low for certain BiSnFEs. An electrode with a Bi(III):Sn(II) ratio of 0.4:0.6 at 0.5 mg/L total mass concentration (i.e. a final solution containing 0.2 mg/L Bi(III) and 0.3 mg/L Sn(II) to form an in situ electrode) demonstrated the greatest accuracy and precision for simultaneous analyte ion determination. Therefore, improved analytical performance can be obtained using BiSnFE compared to pure BiFE. This work also reports for the first time the use of the electrochemical impedance spectroscopy technique to analyse SnFEs and BiSnFEs. The latter analysis showed that the electroanalytical system is under kinetic- and diffusion-controlled processes for SnFEs, whereas BiSnFE is under a kinetic-controlled process. A possible interference effect on the Zn(II), Cd(II), and Pb(II) stripping signals was tested for the presence of Fe(II), As(III), Na(I), K(I), Ca(II), Mg(II), Cu(II), Sb(III), and NO3− ions in the analysed solution. Finally, an analysis of tap water was performed using an electrode with a Bi(III):Sn(II) ratio of 0.4:0.6 at 0.5 mg/L total mass concentration.

Bismuth nanodendrites deposited on glassy carbon electrode as a sensitive electrochemical sensor for simultaneous detection of Cd2+ and Pd2+ ions

AbstractIn this study, bismuth nanodendrites (BiNDs) were fabricated on glassy carbon electrode by chronopotentiometric method. The hierarchical structure and high population matrix of BiNDs provides high surface active area to enhance the electrochemical signals of measured Cd2+ and Pb2+ ions. The developed bismuth nanodendritic structure was well‐observed and characterzied by scanning electron microscopy (SEM). Electrochemical behaviours of developed BiNDs electrodes were studied by the cyclic voltammetric (CV) method. The fabrication conditions for BiNDs such as the applied current and deposition time were optimized as ‐10 mA and 90 s, respectively. Under this optimized condition, the highest peaks of Cd2+ and Pb2+ ions at concentration of 20 ppb were obtained. The Cd2+ and Pb2+ signals acquired by BiNDs are almost three times greater than that measured by the Bi film electrode.

Electrochemical behavior of Dy(III) on bismuth film electrode in eutectic LiCl-KCl melts

An electrochemical study of dysprosium (III) on Bi film electrode was carried out in eutectic LiCl-KCl melts by transient and steady state electrochemical techniques. The results of transient electrochemical techniques showed that the reduction of Dy (III) appears at a more positive value than the one detected on W electrode owing to the formation of Bi-Dy intermetallic compounds through electrochemical deposition of Dy on bismuth film electrode. The thermodynamic properties of the formation for Dy-Bi intermetallics were estimated by a steady state electrochemical method in a temperature range of 713–803 K. Furthermore, the electrochemical preparation of Bi-Dy alloys was conducted by galvanostatic electrolysis at different current intensities. The Bi-Dy alloys, characterized by scanning electron microscopy equipped with energy dispersive spectrometry and X-ray diffraction, are comprised of DyBi3/5 and DyBi phases.

Development of Anodic Stripping Voltammetry in Alkaline Electrolyte and Application for Screening Anion Diffusion Selectivity in Battery Separators

Anodic stripping voltammetry (ASV) is a well-known powerful, sensitive, and selective analysis technique used for the detection of metal ion species in solution. While ASV was initially developed with mercury (Hg) as the plating electrode more recent applications have used bismuth (Bi) as a less toxic and less oxygen sensitive electrode that has low background currents, better reproducibility, and little to no need for electrode conditioning, as compared to Hg electrodes. ASV is most commonly performed under neutral to acidic electrolyte conditions where metals, as metal cations are readily soluble; however, the extension of an ASV method into highly alkaline environments (pH > 14) could prove useful for the in situ electrolyte monitoring of alkaline batteries and fuel cells such that potential diagnostics of their performance vs. electrolyte composition could be realized. With this in mind, we recently extended the ASV method to highly alkaline electrolytes, in order to determine Zn diffusion across separator membranes.[1] Zinc (Zn) alkaline battery chemistries such as Zn/MnO2 and Zn/Air are currently attracting a lot of attention due to their potential as safe, low cost, high energy density rechargeable batteries. A main failure mechanism for these cells is the poisoning of the cathode material during cycling due to Zn crossover from the anode to the cathode. Advanced separators that successfully stop or limit this crossover are crucial in order to increase the cycle lifetime of these batteries. ASV, utilizing a Bi film, along with cadmium (Cd) and lead (Pb) as the plating mediators, was utilized to determine Zn concentrations in highly alkaline environments (30% NaOH or 35% KOH). To evaluate the utility of this assay, zincate diffusion through commercial off-the-shelf (COTS) Celgard 3501 and Cellophane 350P00 membranes was monitored using both ASV and inductively coupled plasma – mass spectrometry (ICP-MS) methods. The obtained zincate diffusion coefficients for both techniques are shown to compare favorably. While the traditional complexometric or elemental analysis methods can take days to weeks to determine Zn membrane diffusion metrics, this ASV method provides a real-time measurement which significantly increases the throughput for the screening of these membranes. During our development of an ASV method for Zn, we realized that in general there was a lack of ASV methods in highly alkaline electrolyte and hence turned our attention to the development of an ASV method for the determination of Cu, as cuprate [Cu(OH)4 2-]. Cu has been notoriously difficult to measure by ASV, even under acidic conditions.[2] In fact, most studies using Bi film electrodes for the direct determination of Cu have deemed it impossible and thus studies for the determination of the Cu concentration in a matrix are normally still performed separately with Hg electrodes. After investigation of potential metal film electrodes and mediators including Cd, Ag, Sb, and Zn, it was found that lead (Pb) serves as a good mediator for the plating of Cu in highly alkaline solutions which permits the replacement of the interfering Bi film electrode. Various aspects of this work will also be presented. [1]. J. Duay, T. N. Lambert and R. Aidun “Stripping Voltammetry for the Real Time Determination of Zinc Membrane Diffusion Coefficients in High pH: Towards Rapid Screening of Alkaline Battery Separators” Electroanalysis 2017, 29, 2261-2267. [2]. J. Duay, J. E. Ortiz-Santiago and T. N. Lambert “Copper Sensing in Alkaline Electrolyte Using Anodic Stripping Voltammetry by means of a Lead Mediator” Electroanalysis 2017, DOI: 10.1002/elan.201700526. This work was supported by the Laboratory Directed Research and Development program at Sandia National Laboratories. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. Dr. Imre Gyuk, Energy Storage Program Manager, Office of Electricity Delivery and Energy Reliability is also thanked for financial support of this project.

Copper Sensing in Alkaline Electrolyte Using Anodic Stripping Voltammetry by Means of a Lead Mediator

AbstractAnodic stripping voltammetry (ASV) is an analysis technique that permits the selective and quantitative analysis of metal ion species in solution. It is most commonly applied in neutral to acidic electrolyte largely due to inherent metal ion solubility. Bismuth (Bi) is a common film used for ASV due to its good sensitivity, overall stability and insensitivity to O2. ASV, utilizing a Bi film, along with cadmium (Cd) and lead (Pb) as the plating mediators, has recently been adapted to determine zinc (Zn) concentrations in highly alkaline environments (30 % NaOH or 35 % M KOH). Successful analysis of Zn in alkaline relies on the ability of the hydroxide to form soluble metal anion species, such as Bi(OH)4− and Zn(OH)42−. Here, we look to extend this technique to detect and quantify copper (Cu) ions in these highly basic electrolytes. However, in general, the use of ASV to detect and quantify Cu ion concentrations is notoriously difficult as the Cu stripping peak potential overlays with that of Bi from the common Bi film electrode. Here, an ASV method for determining Cu concentration in alkaline solutions is developed utilizing Pb as a deposition mediator. As such, it was found that when analyzing Cu solutions in the presence of Pb, the stripping voltammetry curves present separate and defined Cu stripping peaks. Different analyzes were made to find the best stripping voltammetry performance conditions. As such, an accumulation time of 5 minutes, an accumulation potential of≤−1.45 V vs. Hg/HgO, and a concentration of 35 wt% KOH were determined to be the conditions that presented the best ASV results. Utilizing these conditions, calibration curves in the presence of 5.0 ppm Pb showed the best linear stripping signal correlation with an r‐squared value of 0.991 and a limit of detection (LOD) of 0.67 ppm. These results give way to evaluating Cu concentrations using ASV in aqueous alkaline solutions.

Flexible liquid crystal polymer-based electrochemical sensor for in-situ detection of zinc(II) in seawater

The authors describe a liquid crystal polymer (LCP) based bismuth (Bi) film electrode that can be directly deployed for in-situ determination of zinc(II) ions. The use of an LCP warrants improved operational reliability, high durability, and flexibility of the sensor, allowing it to be mounted on any flat or shaped surface. Square wave anodic stripping voltammetry shows the sensor to be able to detect Zn(II) (−1.64 V vs. thin-film Ag/AgCl reference electrode) in concentrations as low as 1.22 nM at a deposition time of 180 s. Other figures of merit include (a) an analytical sensitivity of 1.55 nA∙nM−1∙mm−2, (b) a linear detection range extending from 4.59 to 1071 nM, (c) a repeatability with a relative standard deviation of 3.35% (for n = 10), (d) a reproducibility with a relative standard deviation of 1.64% (for n = 6). Real-time applicability of the sensor for in-situ detection was demonstrated by determination of Zn(II) in seawater. In an extension of the method, a flexible sensor array consisting of four LCP-based sensors was attached to the hull of an autonomous kayak, which was remotely operated. The response of the sensor array indicated a clear trace of Zn(II) concentrations in seawater. This was confirmed by ICP-MS analysis. The results suggest the potential usage of the flexible LCP electrochemical sensor for in-situ monitoring.

Electrochemical formation and thermodynamic properties of Tb–Bi intermetallic compounds in eutectic LiCl–KCl

The electrochemical formation and thermodynamic properties of Tb–Bi intermetallic compounds were investigated on a Bi film electrode in eutectic LiCl–KCl.

Electrochemical Extraction of Holmium and Thermodynamic Properties of Ho-Bi Alloys in LiCl-KCl Eutectic

The electrochemical reduction of Ho (III) on W electrode and liquid Bi film electrode was investigated in LiCl-KCl eutectic by various electrochemical techniques. The reduction reaction of Ho (III) was found to be diffusion-controlled process with three electrons exchanged, which was considered as quasi-reversible. The diffusion coefficient of Ho (III) was determined by cyclic voltammetry and chronopotentiometry. The results of cyclic voltammetry and square wave voltammetry obtained on Bi film electrode exhibited two new reduction peaks at less negative potential than that on W electrode due to the formation of different Ho-Bi intermetallic compounds. Furthermore, the thermodynamic properties on the formation of Ho-Bi intermetallic compounds were measured using open circuit chronopotentiometry in the temperature range from 773 K to 863 K. The electroextraction of holmium was performed on liquid Bi electrode by potentiostatic and galvanostatic electrolysis. The extractive products were characterized by scanning electron microscopy and energy dispersive spectrometry (SEM-EDS) and X-ray diffraction (XRD). It was showed that Ho-Bi alloys consisted of HoBi and Bi phases. The concentration of Ho (III) was monitored by square wave voltammetry and analyzed by inductive coupled plasma atomic emission spectrometer (ICP-AES). The calibration curve was obtained on linear relationship of peak currents and concentration of Ho (III). Meanwhile, the extraction efficiencies were calculated by ICP-AES and calibration curve, respectively, the highest extraction efficiency could reach 95.9% by potenostatic electrolysis at −1.6 V for 27 h.

Preparation of dendritic bismuth film electrodes and their application for detection of trace Pb (II) and Cd (II)

In this paper, dendritic Bi film electrodes with porous structure had successfully been prepared on glassy carbon electrode using a constant current electrolysis method based on hydrogen bubble dynamic templates. The electrode prepared using a large applied current density showed an increased internal electroactive area and a significantly improved electrochemical performance. The analytical utility of the prepared dendritic Bi film electrodes for the determination of Pb (II) and Cd (II) in the range of 5–50μg·L−1 were presented in combination with square wave stripping voltammetry in model solution. Compared with non-porous Bi film electrode, the dendritic Bi film electrode exhibited higher sensitivity and lower detection limit. The prepared Bi film electrode with dendritic structure was also successfully applied to real water sample analysis.

Determination of the Free Metal Ion Concentration Using AGNES Implemented with Environmentally Friendly Bismuth Film Electrodes.

Ex situ plated Bi film electrodes (Bi-FE) have been employed, for the first time, to measure the free concentration of Pb(II) in aqueous solutions using absence of gradients and Nernstian equilibrium stripping (AGNES) with stripping chronopotentiometry (SCP) quantification. The amount of deposited Pb°, below a certain threshold, follows a Nernstian relationship with the applied potential. This threshold can be interpreted as the frontier of transition from surface deposition to solid (bulk) formation of Pb°. AGNES with Bi-FE yielded a very good detection limit (3σ) for Pb(II) of 6.0 × 10(-9) M with an applied gain of 398 and a deposition time of 400 s. The ability of the Bi film electrode to perform speciation measurements was demonstrated for Pb(II)-PSS and Pb(II)-IDA systems. The measured values with the Bi-FE were in good agreement with the values obtained using the Hg film electrode and/or the values reported in the literature.

Overoxidation of Conducting Polymers Combined with In Situ Plated Bismuth Film: An Approach for Simultaneous Detection of Cadmium and Lead Ions

Thiolated poly(m-phenylenediamine) (PmPD), overoxidized in NaOH solution, was used in combination with in situ plated Bi film electrode for simultaneous and sensitive analysis of Cd2+ and Pb2+ by square wave anodic stripping voltammetry (SWASV). Thiolation of PmPD was achieved during the electropolymerization of m-phenylenediamine, and the introduced S atoms improved the preconcentration efficiency of the PmPD for Cd2+ and Pb2+; and overoxidation altered the surface structure of the polymer, which endowed more active area for the nucleation of Bi. Due to the synergetic effect of thiolation, overoxidation and Bi film, the prepared PmPD modified Bi film exhibited excellent performances in the simultaneous analysis of Cd2+ and Pb2+, showing a linear range from 6 to 240 μg L−1 for Cd2+ and Pb2+. The detection limits were 0.02 μg L−1 for Cd2+ and 0.04 μg L−1 for Pb2+, respectively. This approach opens a new avenue to monitor trace heavy metal ions precisely and rapidly.

Electrochemical reactions of the Th4+/Th couple on the tungsten, aluminum and bismuth electrodes in chloride molten salt

This work concerns the electrochemical behaviors of Th4+ on the tungsten, aluminum and bismuth electrodes in the LiCl-KCl eutectic, respectively, at 773K. Cyclic voltammetry and square wave voltammetry were employed to investigate the cathodic reduction of Th4+. The results demonstrate that the reduction of Th4+ is a one step process with a transfer of 4 electrons. The reversibility of the Th4+/Th couple on the bismuth film and tungsten electrodes is directly confirmed by the CV. The diffusion coefficient is also calculated to be (2.23±0.16)×10−5 and (7.19±0.12)×10−5 cm2/s by applying both cyclic voltammetry and chronopotentiometry, respectively. A series of redox couples were confirmed to be associated with the formation of different kinds of Al-Th intermetallic compounds. Compared to Al electrode, a cathodic shift of the reduction potential of the Th4+ is observed on the Al film electrode which is not conducive for the potentiostatic extraction of thorium. The cathodic depolarization gives a shift of 420mV on the Al electrode, while 490mV on the Bi film electrode for the reduction of Th4+ compared to the inert W electrode. The reduction potential of Th4+ on the Bi film electrode is 70mV more anodic than that on the Al electrode. Potentiostatic electrolyses were carried out on an Al plate and Bi liquid electrode to confirm the formation of the Th alloys. Two Al-Th alloys (Al3Th and Al2Th) and one Bi-Th alloy (Bi2Th) were obtained, respectively.

In situ synthesis and properties of reduced graphene oxide/Bi nanocomposites: As an electroactive material for analysis of heavy metals

An in situ modified Hummers method (without the use of any surfactants) has been used for the deposition of bismuth (Bi) nanoparticles onto the surface of reduced graphene oxide (RGO) sheets. The as-synthesized nanocomposites were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, transmission electron microscopy (TEM), thermogravimetry (TG) and differential scanning calorimetry (DSC). The morphology of the RGO/Bi nanocomposites provides a better choice as an electrode material for detection of heavy metal ions due to its better functional properties over the Bi film electrode. Trace analysis of heavy metal ions like Cd+2, Pb+2, Cu+2 and Zn+2 in water is carried out by stripping voltammetric analysis using RGO/Bi nanocomposite as an electrode material. The sensitivity and detection limit of the electrode were quantitatively estimated from the analysis. The three sigma detection limits at different deposition potential for Cd2+, Pb2+, Zn2+ and Cu2+ were obtained as 2.8, 0.55, 17 and 26μgL−1, respectively. Copper detection using Bi-film electrode was a major challenge, which has been resolved using the RGO/Bi nanocomposite electrode.

Reliability Evaluation of Nano-Bi/Silver Paste Sensor Electrode for Detecting Trace Metals

The reliability of sensor characteristics for a nano-bismuth (Bi)/silver (Ag) paste electrode has been investigated by comparison with Hg/Bi film electrodes in terms of accuracy and precision. Using Ag paste instead of carbon paste as a conducting layer, the sensitivity and detection limit of the sensor electrode were more enhanced due to a lower electrical conductivity of Ag. For the evaluation of detecting ability, the Zn, Cd, and Pb ion concentrations of the prepared standard solutions were experimentally measured on Hg film, Bi film, and nano-Bi electrodes using anodic stripping voltammetry. A nano-Bi electrode can detect Zn, Cd, and Pb ions at 0.1 ppb with higher precision and accuracy compared with Hg film and Bi film electrodes. From the trace analyses of Zn, Cd, and Pb ions in commercial drinking water and river water using a nano-Bi electrode and inductively coupled plasma (ICP) technique, it was concluded that the nano-Bi electrode exhibited excellent sensing characteristics with high reliability, and could detect even traces of Zn, Cd, and Pb ions that were not detected by the ICP method.

Simultaneous Determination of Copper(II), Lead(II) and Zinc(II) at Bismuth Film Electrode by Multivariate Calibration

AbstractIn this work, simultaneous determination of Cu(II), Pb(II) and Zn(II) ions at low concentration levels (ppb) by square wave anodic stripping voltammetry on a Bi(III) film electrode plated in situ at a glassy carbon electrode (GCE) is described. A chemometric approach was used to overcome the overlapping peaks of Cu(II) and Bi(III), the competition of the electrodeposited Cu and Bi for the surface of the GCE and the formation of Cu‐Zn intermetallic compounds. The construction of the multivariate calibration models, based on partial least squares regression, allowed the simultaneous determination of Cu (in the concentration range 8.0 to 20.1 ppb), Pb (2.0 to 30.0 ppb) and Zn (29.7 to 90.4 ppb) with most of the prediction errors obtained in the external validation set for the three models lower than 16, 11 and 26 %, respectively. Finally, this method was used for the determination of these trace metal ions in surface river water samples with satisfactory results [errors below 10, 5 and 32 % for Cu(II), Pb(II) and Zn(II), respectively].