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One-Pot Electrochemical Synthesis of Lead Oxide-Electrochemically Reduced Graphene Oxide Nanostructures and Their Electrocatalytic Applications
Abstract
In this study, a new electrochemical method for the cathodic electrodeposition of lead oxide-electrochemically reduced graphene oxide (PbO-ERGO) from an aqueous solution was carried out in one-pot in the same solution containing Pb2+ and graphene oxide, leading to the direct formation of crystalline thin films at near-room temperature. XRD was employed to determine the crystallinity index of the PbO-ERGO nanostructures. SEM, XPS, EDS and UV–visible spectroscopy techniques were employed to analyze the morphological, structural, and optical characteristics of the composite materials. Owing to the rapid charge transport in the composite materials of PbO-ERGO, rapid, uniform photocurrent responses were observed. In addition, the PbO-ERGO composite electrode exhibited a 40 and 130 fold increase in the photocatalytic performance compared to PbO and ERGO electrodes, respectively. Then, the nanocomposite-modified electrode was applied for the non-enzymatic sensing of H2O2. A linear amperometric response to H2O2 was observed at concentrations in the ranging from 1 ×10 -5 to 10 ×10 -3 mol L -1. The sensitivity and detection limit of the PbO-ERGO electrode were estimated as 2.26 μ A mM-1 cm-2 and 2 x 10-7 mol L -1, respectively, at a signal-to-noise ratio of 3.0.
... Lead monoxide (PbO) is one type of lead-based compounds that attracted many focuses due to its excellent properties such as electrical, mechanical, and optical [1]. It is a photoactive semiconductor material and an important industrial material which has been used widely as gas sensors, pigments and paints, storage devices, UV blockers and as modifiers in oxide glasses [4][5][6]. Specially, the 2D of PbO recently attracted many attentions due to its excellent nonlinear optical response and light sensitivity in the visible region [7,8]. These materials have two polymorphic, namely a red α-PbO that has a tetragonal structure (litharge) which is stable at low temperature with P4nmm space group and yellow β-PbO that has orthorhombic structure (massicot) stable at high temperature with Pbcm space group [2,3,9]. ...
... In the present study we focused on β-PbO polymorphs. Although different techniques such as solvothermal [11], electrochemical [5], co-precipitation [12], green methods [3,13], microwave-assisted method [14], thermolysis [15], ball milling [16], sonochemical [17,18], solid-state thermal decomposition [19], laser ablation [20], thermal decomposition [21], sol-gel [22,23], have been applied for the synthesis of β-PbO, still there is lack of theoretical studies on this material. Recently, many first principle calculations DFT based for α-PbO have been reported. ...
The β-PbO has low electrical conductivity relative to α-PbO which hinders its application in optoelectronics and other technological devices. The structural, electrical, and optical properties of Co2+, Ni2+, Cu2+, Li+, and Sn2+-doped β-PbO at the Pb site were investigated in this work using Quantum espresso as a DFT tool. The GGA and LDA exchange functionals were used for band structure calculations. The indirect band gap property is indicated by the calculation of electronic band structure, with spin up state band gap values of 2.28 eV, 0.68 eV, 1.01 eV, 1.57 eV, 1.79 eV, and 1.76 eV for pristine, Co2+, Ni2+, Cu2+, Li+, and Sn2+-doped β-PbO, respectively. The spin down states band gap of Co2+ and Ni2+ was 0.1 eV and 0.32 eV, whereas other dopants and pristine β-PbO equal with spin up states. The PDOS calculation shows how each orbital contributes to the formation of deep level valence band, shallow level valence band, and conduction band states. Dopant effects on optical properties such as JDOS, dielectric functions, refractive index, extinction coefficient, reflectivity, absorption coefficient, electron energy loss spectrum, and optical conductivity were thoroughly discussed. This research provides in-depth functional characteristics for guiding laboratory working experiments and the applications of these materials in various fields such as energy storage and solar cells.
... PbO nanoparticles can be synthesized by physical, chemical, and biological methods. Moreover, PbO nanoparticles have been synthesized by different methods such as sol-gel [14], solvothermal [15], electrochemical [16], oxidation of lead sheets [17], co-precipitation [18], green methods [2,19], microwave-assisted method [20], hydrothermal [21], sonochemical [22], thermolysis [23], ball milling [24], laser ablation [25], thermal decomposition [26,27] for various applications. ...
This work employs DFT to investigate the effect of metal doping (Li, Sn, Ni, Cu, and Co) on the optical, electrical, and structural characteristics of α-PbO. Li-doped α-PbO is the only doped material whose volume was increased in the structural investigation. Thus, for pristine, Li-doped, Sn-doped, Ni-doped, Cu-doped, and Co-doped α-PbO, the obtained a lattice parameters were 4.066, 4.192, 3.955, 3.922, 3.820, and 3.799 nm, respectively, and the c lattice parameters were 5.26, 5.622, 4.953, 3.907, 3.672, and 3.551 nm, respectively. The indirect bandgap values of pristine, Li-doped, Sn-doped, Ni-doped, Cu-doped, and Co-doped α-PbO were found to be 1.78, 1.59, 1.56, 1.25, 1.33, and 1.13 eV, respectively. The partial density of states (PDOS) shows the contribution of Pb 6s for deep valence states, O 2p for shallow valence states, and Pb 6p orbitals for conduction band states. Comprehensive analyses were conducted on the impacts of doped metals on optical properties, including dielectric functions, electron energy loss, optical conductivity, refractive index, extinction coefficient, and reflectivity. This study offers useful guidelines for doing experiments with metal oxides in various fields, including energy storage and photocatalysis.
The layered structure and calculated electronic structure of metal doped litharge PbO
... In nanocomposite structures, the presence of rGO surface is a candidate to solve the problem of aggregation of nanoparticles during production, since it is a successful support material for the dispersion of nanoparticles [29]. Previously, the rGO surface has been decorated with many metal nanoparticles (Pd [30], Ni [31], Cu [32], etc.), metal oxides (ZnO [33], TiO 2 [23], PbO [34], CuO [35], Cu 2 O [36], SnO [37], etc.), and conductive polymers (poly(3,4-ethylene dioxythiophene) [38], polyaniline [39], polypyrrole [40], etc.). rGO was used as a support material for the dispersion and stabilization of the nanoparticle type. ...
There is an increasing demand for developing more sensitive sensors for determining nitrite, which has potential use in wastewater, food preservatives, and corrosion inhibitors. Here, we designed a CuBi2O4/rGO nanocomposite via simultaneous electrochemical deposition of GO and CuBi2O4. Then, the nanocomposite surface was electrochemically functionalized with Ag nanoparticles. Analytical and morphological characterizations showed that nanocomposites were synthesized with high purity and crystallinity. Finally, the electrocatalytic activity of the prepared Ag@CuBi2O4/rGO electrode was investigated as an electrochemical sensor application in nitrite detection. Ag@CuBi2O4/rGO had a higher faradaic current than CuBi2O4/rGO and PGE. The modified electrode exhibited high selectivity with low nitrite oxidation potential (+ 0.8 V) and detection limit (0.18 µM). The detection limit for nitrite is lower than that of most reported materials.
... The higher peak intensity of Pb-O bonds presented the more content of the PbO formation with an energy separation of 4.9 eV. [35][36][37][38][39] In Fig. 3d, the de-convoluted O 1s state shows the signal peak that can be tted from ve peaks by Gaussian-Lorentzian curves. The deconvoluted peaks can be divided into ve types of oxygen species with the binding energies at 529.9 eV, 530.9 eV, 531.9 eV, 532.9 eV and 534.2 eV. ...
1,1-Dimethyl-4,4-bipyridinium dichloride known as paraquat is a popular well-known herbicide that is widely used in agriculture around the world. However, paraquat is a highly toxic chemical causing damage to vital organs including the respiratory system, liver, heart, and kidneys and death. Therefore, detection of paraquat is still necessary to protect life and the environment. In this work, an electrochemical sensor based on lead oxide nanoparticles (PbO-NPs) modified on a screen-printed silver working electrode (SPE) has been fabricated for paraquat detection at room temperature. The PbO-NPs have been synthesized by using a sparking method via two Pb metal wires. The electrochemical paraquat sensors have been prepared by a simple drop-casting of PbO-NPs solution on the surface of the SPE. The PbO-NPs/SPE sensor exhibits a linear response in the range from 1 mM to 5 mM with good reproducibility and high sensitivity (204.85 μA mM-1 cm-2) for paraquat detection at room temperature. The PbO-NPs/SPE sensor shows high selectivity to paraquat over other popular herbicides such as glyphosate, glufosinate-ammonium and butachlor-propanil. The application of the PbO-NPs/SPE sensor is also demonstrated via the monitoring of paraquat contamination in juice and milk.
... G is a promising nanomaterial for the formation of nanocomposites with metal oxide due to its economy, ease of functionality with other molecules, and easy synthesis approaches [19][20][21][22][23][24][25][26][27]. For the synthesis of G, the reduction of graphene oxide (GO) using various techniques such as chemical, electrochemical, hydrothermal, or photochemical is often used [28,29]. ...
In this study, the preparation of tin(II) oxide/reduced graphene oxide (SnO/rGO) hybrid electrodes was simultaneously performed by a one-pot electrodeposition process for the first time by using a single cell. The morphological and structural characterizations of SnO/rGO were performed by scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Additionally, the electrocatalytic activities of the electrode materials for the determination of DA were tested by the linear sweep voltammetry technique. Furthermore, the amperometric sensing of DA was carried out with a detection limit of 0.32 µM. The results suggest that our fabricated biosensor exhibited an ultrahigh sensitivity, low detection limit, and excellent selectivity.
... 30,31 Thus, some progress has been reported in the graphene-based film prepared by direct electrodeposition on the surface of electrodes for electrochemical sensing. [32][33][34] Recently, we presented direct electrodeposition fabrication of reduced graphene oxide-water soluble cationic pillar [6]arene composite film. 35,36 The prepared film demonstrates higher electrochemical response to various analytes (e.g., adenine, guanine, ascorbic acid, folic acid and so on) than that of ErGO film. ...
On the surface of a glassy carbon electrode, electrochemically reduced graphene oxide-cationic pillar[6]arene (ErGO-CP6) composite film was constructed using a pulsed potential method. UV-vis spectra, SEM, Raman spectra and electrochemical experiments were applied to characterize the composite film. It was then used as a new electrochemical sensing platform for determination of thiamethoxam. Due to the synergistic effect of ErGO and CP6, this composite film shows a higher sensitivity and better selectivity toward thiamethoxam than that of ErGO film. The linear range from 1.0 × 10-7 to 1.3 × 10-5 mol L-1 was obtained by differential pulse voltammetry. Meanwhile, the method was applied to cucumber and tomato samples in a recovery test. The recovery was between 92.0% and 98.7%, and the results are satisfactory. This study presents a promising electrochemical sensing platform for rapid and sensitive analysis of thiamethoxam.
On the surface of glassy carbon electrode, electrochemically reduced graphene oxide-anionic pillar[6]arene (ErGO-AP6) composite film is directly constructed using a potentiostatic method. This composite film is used as an electrochemical sensing platform for detecting clothianidin (CLO). Studies on the interaction mechanism reveal a higher supramolecular recognition capability between AP6 and CLO, compared to that between β-cyclodextrin (β-CD) and CLO. Owing to the synergistic effect of ErGO and AP6, the ErGO-AP6 composite film shows an outstanding sensitivity and excellent selectivity towards CLO, superior to that of ErGO-β-CD film. The linear range from 1.0 × 10⁻⁷ to 5.0 × 10⁻⁵ mol L⁻¹ and detection limit of 4.0 × 10⁻⁸ mol L⁻¹ for CLO are achieved. In addition, the presented method is used for fruit and water samples in a recovery test, showing recovery rates between 90.0% and 99.4%. This study provides a promising electrochemical sensing platform for rapid and sensitive analysis of CLO.
Electrochemically reduced graphene oxide/zinc oxide (ERGO/ZnO) nanocomposite was simultaneously co-electrodeposited based on a one-step electrodeposition approach at room temperature on an indium tin oxide (ITO) electrode from an aqueous solution without using specific reducing agents. The electrochemical fabricated ITO-ERGO/ZnO electrode was characterized using field emission scanning electron microscopy (FESEM), X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and electrochemical impedance spectroscopy (EIS) techniques. The biosensor properties of the ITO-ERGO/ZnO electrodes were investigated in terms of their response toward uric acid (UA) sensing via enzyme-free amperometry. The linear current response for UA on the ITO-ERGO/ZnO electrode in the concentration range of
with a sensitivity of
cm
−2
mM
−1
was obtained. The main advantage of the ITO-ERGO/ZnO electrode was a relatively low detection limit for estimating UA, high selectivity, good repeatability, and long-term stability. In addition, the fabrication procedure of the designed biosensor was straightforward, practicable, and inexpensive.
The reduction of graphene oxide is one of the most important methods for the preparation of large-scale, high-quality, and low-cost graphene. Among various reduction methods, the electrochemical reduction has the advantages of eco-friendliness, high efficiency, energy-saving, and good controllability. The produced graphene, electrochemically reduced graphene oxide (ERGO), is grown in-situ on electrodes and can be directly used as an excellent electrode material. This review gives a comprehensive summary of ERGO and the electrochemical reduction of GO. After a brief introduction of the structure and conventional chemical reduction methods of GO, the two approaches of electrochemically reducing GO and the reduction mechanisms are discussed. The influence of experimental parameters on the reduction process and the properties of ERGO are then reviewed. Also, the fabrication of composites based on ERGO is summarized. Finally, the applications of ERGO and its composite materials in electroanalysis, energy conversion and storage, electrocatalysis, and other fields are demonstrated, and the remaining challenges in this field are discussed.
Manganese dioxide/reduced graphene oxide (MnO2/RGO) nanocomposite material was synthesized by the in-situ anodic pulse electrodeposition method to fabricate symmetric supercapacitors. The effects of the pH value of the electrodeposition bath were considered on the properties of fabricated electrodes. Three pH values of 4, 7, and 10 were evaluated, and physicochemical properties were studied using field-emission scanning and transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, nitrogen gas sorption isotherm, and thermogravimetric analysis. The electrochemical evaluation was performed by galvanostatic charge/discharge (GCD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy techniques. The results revealed that the MnO2/RGO nanocomposite prepared at pH = 7 (i.e., MGO7) exhibited a maximum specific capacitance of 693.4 F g⁻¹ at a current density of 0.5 A g⁻¹. The symmetric supercapacitor based on MGO7 was also assessed using GCD and CV tests. Its specific capacitances at current densities of 0.5 and 20 A g⁻¹ were 577.9 and 290.0 F g⁻¹, respectively. The symmetric supercapacitor maintained 79.2% of initial capacitance after 5000 consecutive charge/discharge cycles at a current density of 4 A g⁻¹. The highest energy density of 80.3 Wh kg⁻¹ at the power density of 0.625 kW kg⁻¹ and the highest power density of 25 kW kg⁻¹ at the energy density of 40.3 Wh kg⁻¹ was achieved by the fabricated supercapacitor.
In this study, synthesis of nickel hydroxide-electrochemically reduced graphene oxide on Au electrode (Ni(OH)2/ERGO/Au) was carried out by one-pot electrodeposition process. The as-prepared electrodes were characterized by X-ray powder diffraction spectroscopy, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy, field emission scanning electron microscopy and elemental mapping analysis.The Ni(OH)2/ERGO/Au electrode possessed high specific surface area and sheet-like morphology useful as an electrocatalyst for ethanol fuel cells. The Ni(OH)2/ERGO/Au exhibited the higher current density (~5.2 mA cm⁻²). Due to the excellent electrocatalytic activity and highly stable response of the Ni(OH)2/ERGO/Au, it can be used as a very promising electrocatalyst in direct ethanol fuel cells.
In this study, a nonenzymatic glucose sensor based on a Au electrode was modified using layered poly(3,4-ethylene dioxythiophene) (PEDOT) and electroreduced graphene oxide (ERGO). The modified electrode was characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The electrochemical performance of the electrode material was evaluated to assess its use in glucose sensor applications. In addition, the effect of layer numbers of the layered composite on glucose activity was investigated. The monolayer PEDOT–ERGO nanocomposite exhibited high current density, high sensitivity, and low detection limit of approximately 5 mA cm⁻², 696.9 μA mM⁻¹ cm⁻², and 0.12 μM, respectively. Moreover, an electrode interference test was conducted in the presence of various interfering species such as ascorbic acid, uric acid, dopamine, and H2O2, revealing excellent selectivity of the nonenzymatic glucose sensor. Thus, the PEDOT–ERGO modified Au electrode could be utilized as a promising nonenzymatic glucose biosensor.
Bu çalışmada Au elektrot yüzeyinde CuO-grafen (CuO/G) nanokompozitlerinin tek aşamalı elektrokimyasal sentezi gerçekleştirilmiştir. CuO/G yapılarının analitik karakterizasyonu için XRD ve EDS teknikleri kullanılmıştır. Morfolojik karakterizasyonu ise SEM kullanılarak yapılmıştır. CuO/G kompozitlerinin etanol elektro-oksidasyon reaksiyonunda elektrokatalizör olarak kullanımı incelenmiş ve dönüşümlü voltametri tekniği kullanılarak katalitik özellikleri araştırılmıştır. Etanol oksidasyonu için en yüksek akım yoğunluğu CuO/G kompozitinde elde edilmiştir. Sentezlenen nanokompozit filmin yakıt hücrelerinde elektrot malzemesi olarak kullanılabileceği belirlenmiştir.
Single phase metastable α-AgVO3 microrods with high crystallinity, tetragonal rod-like microstructure, uniform particle size distribution, and good dispersion were synthesized by direct coprecipitation at room temperature. They are shown to be viable peroxidase mimics that catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine in the presence of H2O2. Kinetic analysis indicated typical Michaelis–Menten catalytic behavior. The findings were used to design a colorimetric assay for H2O2, best measured at 652 nm. The method has a linear response in the 60 to 200 μM H2O2 concentration range, with a 2 μM detection limit. Benefitting from the chemical stability of the microrods, the method is well reproducible. It also is easily performed and highly specific.Open image in new windowGraphic abstractSingle phase metastable α-AgVO3 microrods with high crystallinity, tetragonal rod-like microstructure, uniform particle size distribution, and good dispersion can efficiently catalyze the oxidation reaction of peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H2O2 to produce a blue color change.
Abstract Nanostructure composites of lead oxide/copper–carbon (PbO/Cu–C) were synthesized through in situ solvothermal synthesis and heat treatment of PbO/Cu with polyvinylpyrrolidone (PVP) and used as lithium-ion battery anodes. A PbO active particle was embedded in the Cu and PVP–C matrix, accommodating volume changes and maintaining the electronic conductivity of PbO. The composite exhibits superior electrochemical performance, with a capacity of 420 mAh g-1 at a current density of 165 mA g−1, compared with previously reported Pb and PbO composite anodes. The developed anode exhibits >90% capacity retention after 9500 cycles, beginning from the second cycle, at a current density of 5.5 A g−1.
The compound lead oxide sulfate PbSO4.PbO was prepared in our laboratory. The Thermal behavior of PbSO4 was studied using techniques of Thermogravimetry under air atmosphere from 25 to 1200˚C. The identity of both compounds was confirmed by XRD technique. Results obtained using both techniques support same decomposition stages for this compound. The electron microscopic investigations are made by SEM and TEM. The compound is characterized by XRD and the purity was determined by analytical Methods. Also a series of thermogravimetric analysis is made and the ideal condition is determined to convert this compound to pure lead oxide.
Lead oxide (PbO) nanoparticles were chemically synthesized using Lead (II) acetate as precursor. The effects of organic capping agents such as Oleic acid, Ethylene Diamine Tetra Acetic acid (EDTA) and Cetryl Tri Methyl Butoxide (CTAB) on the size and morphology of the nanoparticles were studied. Characterization techniques such as X-ray diffraction
(XRD), Fourier Transform-Infrared spectroscopy (FT-IR), Photoluminescence
(PL) Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive Spectroscopy (EDS) and Transmission Electron Microscopy
(TEM) were used to analyse the prepared nanoparticles for their physical, structural and optical properties. The characterization studies reveal that the synthesized PbO nanoparticles had well defined crystalline structure and sizes in the range of 25 nm to 36 nm for capping agents used and 40 nm for pure PbO nanoparticles.
Recently, sophisticated theoretical computational studies have proposed several new crystal structures of carbon (e.g., bct-C(4), H-, M-, R-, S-, W-, and Z-carbon). However, until now, there lacked experimental evidence to verify the predicted high-pressure structures for cold-compressed elemental carbon at least up to 50 GPa. Here we present direct experimental evidence that this enigmatic high-pressure structure is currently only consistent with M-carbon, one of the proposed carbon structures. Furthermore, we show that this phase transition is extremely sluggish, which led to the observed broad x-ray diffraction peaks in previous studies and hindered the proper identification of the post-graphite phase in cold-compressed carbon.
An ultrasensitive platform is presented for the determination of hydrazine by combining the high specific surface area and
higher electrical conductivity of poly(sodium styrenesulfonate) (PSS) graphene nanocomposite film with amperometric detection.
The PSS-graphene were synthesized by the Hummers method and used to modify a glassy carbon electrode. The material was characterized
by scanning electron microscopy and is found to be suitable for sensing hydrazine. The overpotential of hydrazine on the modified
electrode is 0.31V which is lower than in many electrochemical sensors. The calibration curve for hydrazine is linear in
the range from 3.0 to 300µmolL−1, and the detection limit is as low as 1µmolL−1. This is the first report in which such a high sensitivity and low limit of detection has been achieved. It is concluded
that PSS graphene represents an efficient electron mediator for sensing hydrazine.
KeywordsGraphene-Hydrazine-Modified electrode-Electrocatalysis-Amperometry
Graphene was synthesized chemically by Hummers and Offeman method and the graphene-modified electrode was applied in selective determination of dopamine with a linear range from 5 μM to 200 μM in a large excess of ascorbic acid. Selective detection was realized in completely eliminating ascorbic acid, different from the methods based on the potential separations. π–π stacking interaction between dopamine and graphene surface may accelerate the electron transfer whereas weaken the ascorbic acid oxidation on this graphene-modified electrode. The resulted graphene-modified electrode also showed a better performance than multi-walled carbon nanotubes-modified electrode. The phenomena were considered from the elusive two-dimensional structure and unique electronic properties of graphene.
Pb-Cu heterobimetallic precursor complex 1, Pb2(OAc) 4(μ-O)3Cu6(dmae)4Cl 4•(C7H8)•1.7(H2O) [dmae = N,N-dimethylaminoethanolate ((CH3)2NCH2CH 2Ō), OAc = acetate (CH3COŌ)] was synthesized through a simple chemical route and crystallized in the monoclinic space group C2/c. The precursor was characterized by its melting point, elemental composition, FT-IR, MS and by X-ray single crystal structure determination. Thin films were deposited by aerosol assisted chemical vapor deposition on a glass substrate and characterized for adhesion, SEM/EDX and XRD. These studies reveal it to be a suitable precursor for the deposition of Cu-PbO ceramic composite thin films at a relatively low temperature of 450 °C.
A new approach has been used to prepare nanostructured lead oxide-carbon PbO-C composites via the spray pyrolysis technique. In this study, the electrochemical performance of the PbO-carbon nanocomposites as anode materials for lithium-ion rechargeable batteries was investigated. The prepared powders consist of fine nanocrystalline PbO homogeneously distributed within an amorphous carbon matrix with highly developed surface area. The estimated average crystal sizes of these nanocomposites from X-ray diffraction XRD patterns are in the range of 26-102 nm. The combination of spray technology and carbon addition increased the specific surface area above 6 m2 g−1 and the conductivity of PbO, improved the specific capacity, and maintained cycle life with a reversible capacity above 100 mAh g−1 beyond 50 cycles. The increase in capacity retention for PbO-carbon compared to that of pure PbO was due to the presence of a conductive and highly developed carbon matrix that can absorb large volume changes during the alloying/dealloying of lead with lithium over the 1.50 to 0.01 V potential range, which yields LixPb alloys 0 x 4.5.
An electrochemical sensor for nonenzymatic hydrogen peroxide (H2O2) detecting based on size controllable preparation of gold nanoparticles (Au) loading on graphene [email protected] oxide ([email protected]2) nanocomposites modified gold electrode (GE) was fabricated. The [email protected]2 nanocomposites were prepared via a facile solvothermal process. Different sizes of Au were controllably prepared and homogenously loaded on the surface of [email protected]2 nanocomposites modified GE using a simple electroless plating method. X-ray powder diffractometer (XRD) combines with Fourier transform infrared spectrum (FTIR) were used to characterize the composition of [email protected]2 nanocomposites. Electrochemical impedance spectroscopy (EIS) was utilized to study the interfacial properties as well as Field emission scanning electron microscopy (FESEM) was employed to characterize the morphologies of different electrodes. The electrochemical properties of electrochemical sensor were investigated by cyclic voltammetry (CV) and i-t curve methods. After all experimental parameters were optimized, the [email protected]2/Au hybrid nanomaterials modified GE (GE ǀ [email protected]2/Au) showed a good performance towards the electrocatalytic reduction of H2O2. A wide linear detection range (LDR) of CV peaks from 1.0 × 10−3 mM to 10.0 mM (R2 = 0.9990) and a low limit of detection (LOD) of 2.6 × 10−4 mM (S/N = 3) was achieved. The proposed electrochemical sensor was quick, selective, sensitive, simple, stable and reliable to quantitative determination of trace H2O2 in contact lens care solutions.
Herein, we report a simple, facile and reproducible non-enzymatic hydrogen peroxide (H2O2) sensor using electrochemically reduced graphene oxide (ERGO) modified glassy carbon electrode (GCE). The modified electrode was characterised by Fourier transform infrared (FT-IR), UV–Visible, scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. Cyclic voltammetric (CV) analysis revealed that ERGO/GCE exhibited virtuous charge transfer properties for a standard redox systems and showed excellent performance towards electroreduction of H2O2. Amperometric study using ERGO/GCE showed high sensitivity (0.3 μA/μM) and faster response upon the addition of H2O2 at an applied potential of − 0.25 V vs Ag/AgCl. The detection limit is assessed to be 0.7 μM (S/N = 3) and the time to reach a stable study state current is < 3 s for a linear range of H2O2 concentration (1–16 μM). In addition, the modified electrode exhibited good reproducibility and long-term stability.
Through electroplating and thermal decomposition by annealing at various temperatures in an oxygen environment, films of PbO2, Pb3O4 and PbO have been synthesised on transparent conducting substrates of indium tin oxide coated glass. Of these films, Pb3O4, α-PbO and β-PbO have a phase pure crystal structure. These films are formed as either nano-scale particles or complete films depending on the electroplating conditions. The complete films demonstrate excellent surface coverage with a thickness of the order of a few microns. The films have been characterised through a combination of x-ray diffraction, scanning electron microscopy and surface profilometry.
In this article, a nonenzymatic sensor based on Ni(OH)2/electroreduced graphene oxide (ERGO)-multiwalled carbon nanotube (MWNT) nanocomposites is fabricated via convenient electrodeposition of Ni(OH)2 nanoparticles on ERGO-MWNT film modified glass carbon electrode (GCE). Graphene oxide (GO) sheets can serve as surfactants to stabilize the dispersion of pristine MWNTs in aqueous solution, rendering a fine coverage of ERGO-MWNT film on GCE during the fabrication process. MWNTs perform as conducting bridges between ERGO sheets to enhance the electron transfer rate in the substrate. By combining the advantages of ERGO and MWNTs, together with electrocatalytic effect of Ni(OH)2 nanoparticles, the well-designed nanocomposites exhibit excellent sensing behavior towards glucose and hydrogen peroxide (H2O2). The linear detection ranges for glucose and H2O2 are 10-1500µM and 10µM-9050µM while the detection limits are 2.7µM and 4.0µM, respectively. Furthermore, a very high sensitivity is achieved with 2042µAmM(-1)cm(-2) estimated for glucose and 711µAmM(-1)cm(-2) for H2O2. These results suggest that Ni(OH)2/ERGO-MWNT nanocomposites thus easily prepared through a green electrochemical method are promising electrode materials for biosensing. Additionally, good recoveries of analytes in real samples like urine and milk confirm the reliability of the prepared sensor in practical applications.
Lead oxide is demonstrated for the first time as the active layer in a Schottky junction photovoltaic device. Thin films of lead were thermally deposited and oxidised to produce polycrystalline films of lead oxide. Different heat treatments yield variations in the ratio of orthorhombic to tetragonal lead oxide that lead to different device performances, where devices with a higher content of orthorhombic PbO show higher power conversion efficiencies of up to 0.17%. Efficiencies are limited by low short circuit currents and further improvements are expected through increased film homogeneity and grain size as well as the implementation of suitable blocking layers to stop current leakage.
A graphene–ZnO (G-ZnO) hybrid was synthesized by one-step electrochemical deposition. During the formation of ZnO nanostructure by cathodic electrochemical deposition, the graphene oxide was electrochemically reduced to graphene simultaneously. Scanning electron microscope images, X-ray photoelectron spectroscopy, X-ray diffraction, Raman spectra, and UV–vis absorption spectra indicate the resulting G-ZnO hybrid presents a special structure and wide UV–vis absorption spectra. More importantly, it exhibits an exceptionally higher photocatalytic activity for the degradation of dye methylene blue than that of pure ZnO nanostructure under both ultraviolet and sunlight irradiation.
Based on the extraordinarily properties of graphene oxide (GO), nickel oxide nanoparticles (NiONPs)/GO/glassy carbon (GC) modified electrode was prepared by electrodeposition of NiONPs on the GC surface previously modified with GO, which was characterized by scanning electron microscope (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The results showed that GO was partially reduced and three-dimensional NiONPs were electrochemically synthesized on the surface of GO. Compared with NiONPs/GC electrode, NiONPs/GO/GC modified electrode exhibited more excellent conductivity, more superior electrochemical capacitive behavior (16-folds) and better electro-catalytic oxidation of glucose, applying for the electrochemical detection of glucose. The linear range for glucose is from 3.13 μM to 3.05 mM with the detection limit of 1 μM. In addition, the effects of common interfering species, including ascorbic acid (AA), uric acid (UA), and NaCl were investigated in detail. The result indicated that these foreign substances did not interfere significantly on the determination of glucose.
Nano-Mn3O4 + PbO2 composite electrode materials with different compositions are prepared by anodic composite electrodeposition in Pb2+ plating solution containing suspended nano-Mn3O4 particles (40–60 nm). The particles are synthesized via one-step homogeneous precipitation at low temperature. The composite materials are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) analyses. The results indicate that the composite composed of γ-Mn3O4 and β-PbO2 is porous and quasi three-dimensional (3D), and its maximum electrochemically effective area ratio (RF) is 72. The capacitance performance of the composite is determined by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and charge–discharge test. The composite shows a high specific capacitance up to 338 F g−1.
Reduced graphene oxide–lead dioxide composite is formed when EGO coated surface is electrochemically reduced along with lead ions in the solution. This composite has been shown to be an excellent material for low level detection of arsenic. Various functional groups present on EGO, in a wide pH range of 2–11, are responsible for the favorable interaction between metal ion and the modified electrode surface and subsequent trace level detection. X-ray photoelectron spectroscopy and Raman spectroscopic techniques confirm the formation of composite and its composition. Thin layer of lead dioxide along with reduced exfoliated graphene oxide has been shown to be responsible for the enhanced activity of the surface. The detection limit of arsenic is found to be 10nM. This study opens up the possibility of using the composites for sensing applications and possibly simultaneous detection of arsenic and lead.
This paper describes a systematic study of the effect of various spray pyrolysis parameters, such as temperature, solution concentration and solution flow rate on the morphology, crystallization process, crystal size, specific surface area and electrochemical performance of in situ prepared α-PbO spherically agglomerated nano-structured powders. Different analytical methods such as XRD, SEM, TEM, BET gas sorption specific surface area measurements and electrochemical tests were performed. Crystallites in the range of 20–120nm and easily dispersed powders were reproducibly prepared by optimization of the spray conditions. An increase of the temperature from 600 to 800°C was found to lead to a three times increase in the average crystal size, from 31 to 102nm. An increase of concentration from 0.15 to 0.5M dramatically suppresses the crystal size from 127 to 25nm. The BET surface area of sprayed PbO powders is increased up to 6.6m2g−1. For such PbO powders applied as anode materials in Li-ion batteries, we have managed to retain a reversible capacity above 60mAhg−1 beyond 50 cycles.
Pd nanoparticles were immobilized on Au disk electrode and kinetics of hydrogen peroxide electroreduction on the Pd electrode in 0.1M H2SO4 solution was investigated using a rotating disk electrode method. The phase and particle size of palladium were characterized by XRD measurements. The morphology of Pd on Au was examined using SEM. We found that the hydrogen peroxide reduction on Pd nanoparticles proceeds via a two-electron process. The reaction order is one with respect to hydrogen peroxide. An apparent activation energy of 55kJmol−1 was calculated from exchange currents at different temperature. The lower activation energy and higher exchange current density demonstrated that hydrogen peroxide reduction has a faster kinetics than oxygen reduction. Electrolyte anions significantly affect hydrogen peroxide reduction activity, and the activity decreases in the order ClO4->HSO4->Cl−, which is consistent with the increasing adsorption bond strength of the anions.
In this study, the electrochemical performance of PbO@C core–shell nanocomposites as an anode material of lithium-ion batteries was reported. The PbO@C nanocomposites were prepared via the pyrolysis of lead benzoate precursor. Compared to the reported Pb-based anodes, the PbO@C nanocomposites exhibited higher reversible capacity and longer cycling life. A reversible capacity of 170mAhg−1 could be maintained after discharging/charging for 50 cycles, which was at least 1.5 times than the previously reported values. The enhanced electrochemical performance was attributed to the presence of carbon shells that could alleviate the large volume-change of Pb particles during the alloying/dealloying process.
The polyaniline-PbO composites of various mass fractions were prepared by in situ polymerisation. The prepared samples were characterised by FTIR, and the dominant peaks confirmed the formation of polyaniline-PbO composites. The SEM study shows a granular agglomerated morphology, and increases with an increase in the lead oxide mass % in polyaniline. Direct current (DC) conductivity (σ
DC) was studied as a function of temperature (T). From these studies, it was found that conductivity increased at higher temperatures due to the polarons hopping from one localised state to another. DSC studies reveal, the decrease in peak temperature from 273°C (pure PANI) to 169.2°C, 193.5°C, 218.4°C, 235.2°C, and 224.2°C, respectively for the various mass fractions (10 %, 30 %, 20 %, 40 %, and 50 %) of polyaniline-PbO composites.
The photovoltaic stability of polymer solar cells (PSCs) can be greatly improved by adopting an inverted device structure. This paper reports high-performance inverted PSCs with lead monoxide (PbO)-modified indium tin oxide (ITO) as the cathodes. A thin PbO layer can effectively lower the work function of ITO from 4.5 to 3.8 eV. The optimal inverted PSCs with poly(3-hexylthiophene) (P3HT) as the donor and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) as the acceptor exhibited high photovoltaic performance: open-circuit voltage of 0.59 V, short-circuit current density of 10.8 mA cm−2, fill factor of 0.632, and power conversion efficiency of 4.00% under simulated AM1.5G illumination (100 mW cm−2). The photovoltaic efficiency is significantly higher than that of the control inverted PSCs with unmodified ITO as the cathode. It is even better than that of the control PSCs with normal architecture, which have an optimal efficiency of 3.5%. The lowering in the work function by the PbO modification is attributed to the charge transfer between PbO and ITO, as evidenced by the X-ray photoelectron spectra.Graphical abstractHighlights► Inverted polymer solar cells with PbO-modified ITO exhibit high performance. ► A thin PbO layer can lower the work function of ITO. ► Lowering in the work function is due to the interactions between PbO and ITO.
Nanostructured thin films of lead sulfide have been synthesized by a new electrochemical approach based on the underpotential deposition (UPD) of Pb and S from the saturated solution of PbS containing excess of PbS particles as a source of Pb2+ and S2− at various temperatures.We have demonstrated that this new electrochemical route is a simple method with several advantages, including better control of the growth conditions and a one-step process to obtain the nanostructures of PbS. Scanning probe microscopy studies indicate that the growth of PbS nanofilms follows a two-dimensional layer-by-layer growth kinetics at the beginning of electrodeposition but a three-dimensional growth dominates after the formation of the first few layers. The results of morphological and structural investigations reveal that PbS nanostructures grown by this method are single-crystalline in cubic structure and have a preferential orientation along the [2 0 0] direction. The optical absorption spectra of PbS nanostructures show the blue-shift with respect to those of the bulk counterpart, which are attributed as quantum-size effect.
Polycrystalline β-PbO pellets were exposed to ozone gas at room temperature. They were oxidized rapidly up to the composition of PbO1.01 for 1 h. Then, a color change from bright yellow to greenish brown and an enhancement of electrical conductivity from 10-11 to 10-3 S cm-1 were observed. The pellets appeared to have been oxidized up to inside uniformly for 10 min by visual observation. Formation of secondary crystalline phases was not detected by X-ray powder diffraction. Differential thermal analysis showed a broad distinct exothermic peak locating at 520 K, which was ascribed to a release of the strain energy accumulated by the room-temperature oxidation. The temperature region corresponded to that of a decrease in conductivity, indicating that the carrier annihilation was closely related to the lattice relaxation. A tentative mechanism that atomic oxygen is a diffusing species with a high rate was proposed.
(Graph Presented) A novel electrochemical process, based on simultaneous underpotential deposition of Pb and S from the same solution containing EDTA, Pb2+, and S2- at a constant potential, is reported. AFM and XRD results indicate that highly crystalline thin films of PbS could be synthesized by this method.
The process of electrodeposition of β-PbO thin films from aqueous solutions of PbII salts has been studied in detail. Contrary to the mechanism assumed in previous studies, thin films of crystalline β-PbO are obtained after cathodic electrolysis in aqueous solutions of various soluble salts of PbII (Pb(NO3)2, Pb(ClO4)2, and Pb(CH3COO)2), and in both the presence and the absence of O2, thus indicating no contribution of OH– generation by electroreduction of NO3– and/or O2 to the formation of β-PbO. A gradual color change is noted: a freshly electrodeposited gray film turns yellow as it dries in air. Drying of the films under controlled atmosphere (Ar or O2), combined with scanning electron microscopy (SEM) observation and X-ray diffraction (XRD) measurement, has revealed that freshly deposited films are of metallic Pb, which are oxidized and converted into β-PbO. Such a reaction is operative only when a freshly electrodeposited activated wet Pb film is in contact with gaseous O2. Despite the rapid conversion of a solid material, the resultant β-PbO thin films are highly crystallized and possess highly ordered internal nanostructure. Elongated nanoparticles (30 nm × 100 nm) are assembled in a regular alignment to compose a large platelet (greater than 10 μm in size) with single-crystalline character, as revealed by transmission electron microscopy (TEM) observation and selected-area electron diffraction (SAED) measurement.
The quantitative X-ray powder diffraction technique has been adapted for the analysis of the lead oxide used in the manufacture of lead-acid batteries.
Size-quantized thin films of PbTe were electrodeposited on Au (1 1 1) substrates using a practical electrochemical method, based on the simultaneous underpotential deposition of Pb and Te from the same solution containing ethylenediamine tetraacetic acid, Pb2+, and TeO32− at a constant potential. These thin films were characterized by X-ray diffraction (XRD), scanning tunneling microscopy (STM), atomic force microscopy (AFM), energy dispersive spectroscopy (EDS), and reflection absorption-FTIR (RA-FTIR). AFM, STM, and XRD results indicate that the growth of PbTe thin films follows the nucleation and two dimensional growth mechanism, resulting in high crystalline films of PbTe (2 0 0) in cubic structure, which was grown at a kinetically preferred orientation on Au (1 1 1). The EDS analyses of the films reveal that Pb and Te are present in an atomic ratio of approximately 1:1. The quantum-confined effect of the PbTe thin films are confirmed by the RA-FTIR measurements.
The incessant demand for energy forces us to seek it from sustainable resources; and concerns on environment demands that resources should be clean as well. Metal oxide semiconductors, which are stable and environment friendly materials, are used in photovoltaics either as photoelectrode in dye solar cells (DSCs) or to build metal oxide p–n junctions. Progress made in utilization of metal oxides for photoelectrode in DSC is reviewed in this article. Basic operational principle and factors that control the photoconversion efficiency of DSC are briefly outlined. The d-block binary metal oxides viz. TiO2, ZnO, and Nb2O5 are the best candidates as photoelectrode due to the dissimilarity in orbitals constituting their conduction band and valence band. This dissimilarity decreases the probability of charge recombination and enhances the carrier lifetime in these materials. Ternary metal oxide such as Zn2SnO4 could also be a promising material for photovoltaic application. Various morphologies such as nanoparticles, nanowires, nanotubes, and nanofibers have been explored to enhance the energy conversion efficiency of DSCs. The TiO2 served as a model system to study the properties and factors that control the photoconversion efficiency of DSCs; therefore, such discussion is limited to TiO2 in this article. The electron transport occurs through nanocrystalline TiO2 through trapping and detrapping events; however, exact nature of these trap states are not thoroughly quantified. Research efforts are required not only to quantify the trap states in mesoporous metal oxides but new mesoporous architectures also to increase the conversion efficiency of metal oxide-based photovoltaics.
Reduction of a colloidal suspension of exfoliated graphene oxide sheets in water with hydrazine hydrate results in their aggregation and subsequent formation of a high-surface-area carbon material which consists of thin graphene-based sheets. The reduced material was characterized by elemental analysis, thermo-gravimetric analysis, scanning electron microscopy, X-ray photoelectron spectroscopy, NMR spectroscopy, Raman spectroscopy, and by electrical conductivity measurements. (c) 2007 Elsevier Ltd. All rights reserved.
A nonenzymatic hydrogen peroxide (H(2)O(2)) sensor was fabricated using the reduced graphene oxide (RGO) and ferroferric oxide (Fe(3)O(4)) nanocomposites as the sensing material. The nanocomposites were synthesized by coprecipitation method and characterized by high-resolution transmission electron microscopy and X-ray diffraction. Results showed that the RGO sheet was evenly decorated by the well-crystallized Fe(3)O(4) nanoparticles. The nanocomposites showed enhanced catalytic ability to the reduction of hydrogen peroxide compared with the RGO, Fe(3)O(4) nanoparticles alone and the mixture materials. The sensor has a quite wide linear range from 0.1mM to 6mM (R(2)=0.990) with less than 5s response time. Moreover, its detection limit is 3.2 μM (S/N=3). The anti-interference ability, long-term stability and potential application in real samples of the sensor is also assessed. This work expands the application of the graphene-based nanomaterials in the sensor areas.
As part of contribution for developing a green recycling process of spent lead acid battery, a nanostructural lead oxide was prepared under the present investigation in low temperature calcination of lead citrate powder. The lead citrate, the precursor for preparation of this lead oxide, was synthesized through leaching of spent lead acid battery paste in citric acid solution. Both lead citrate and oxide products were characterized by means of thermogravimetric-differential thermal analysis (TG-DTA), X-ray diffraction (XRD), and scanning electron microscope (SEM). The results showed that the lead citrate was sheet-shape crystal of Pb(C(6)H(6)O(7)) · H(2)O. When the citrate was calcined in N(2) gas, β-PbO in the orthorhombic phase was the main product containing small amount of Pb and C and it formed as spherical particles of 50-60 nm in diameter. On combusting the citrate in air at 370°C (for 20 min), a mixture of orthorhombic β-PbO, tetragonal α-PbO and Pb with the particle size of 100-200 nm was obtained, with β-PbO as the major product. The property of the nanostructural lead oxide was investigated by electrochemical technique, such as cyclic voltammetry (CV). The CV measurements presented the electrochemical redox potentials, with reversibility and cycle stability over 15 cycles.
We first established a process for the autonomous creation of PbO nanostructures consisting of a simple three-step procedure for both the formation of Pb nanoparticles and their oxidation. Oxygen contacting aqueous media results in an autonomous conversion from electrodeposited Pb particles to PbO nanostructures; i) flower-like PbO structures are placed at the interface of water and oxygen, ii) the growth/burst of PbO nanowires in various directions is observed in the middle of water media, and iii) ultra-thin PbO nano-platelets are dominantly placed onto the substrate. A new mechanistic origin was also proposed based on experimental observations and further suggests that major requirements are essential for the autonomous creation of PbO nanostructures.
Graphene, as the fundamental 2D carbon structure with exceptionally high crystal and electronic quality, has emerged as a rapidly rising star in the field of material science. Its sudden discovery in 2004 led to an explosion of interest in the study of graphene with respect to its unique physical, chemical, and mechanical properties, opening up a new research area for materials science and condensed-matter physics, and aiming for wide-ranging and diversified technological applications. In this critical review, we will describe recent advances in the development of graphene-based materials from the standpoint of electrochemistry. To begin with, electron transfer properties of graphene will be discussed, involving its unusual electronic structure, extraordinary electronic properties and fascinating electron transport. The next major section deals with the exciting progress related to graphene-based materials in electrochemistry since 2004, including electrochemical sensing, electrochemiluminescence, electrocatalysis, electrochemical energy conversion and FET devices. Finally, prospects and further developments in this exciting field of graphene-based materials are also suggested (224 references).
A constant potential electrolytic method for the preparation of a new polypyrrole-lead dioxide composite electrode on glassy-carbon substrate is described. The method involves constant potential electrolysis (CPE) of 1M potassium nitrate containing 2mM lead acetate at + 1.100 V vs. SCE for about 10 min, followed by addition of 25mM pyrrole and subsequent CPE at + 0.800 V for about 2-3 min. The choice of experimental conditions for the preparation and mechanical stability, open circuit potential (ocp) response, background current levels and typical voltammetric response of Mn(2+) in 1M sulphuric acid are also presented and discussed.
Hydrogen peroxide electroreduction on both catalytically active Pt and inactive Au surfaces are studied by using both surface-enhanced Raman spectroscopy (SERS) and density functional theory (DFT) calculations. SERS measurements on Pt show the presence of Pt-OH at negative potentials, which suggests that hydroxide is formed as an intermediate during the electroreduction process. Additionally, the O-O stretch mode of H(2)O(2) is observed on Pt, which shifts to lower energy as potential is swept negatively, indicating that the O-O bond is elongated. For comparison, there is no variation in the energy of the same O-O mode on Au surfaces, and there is no observation of Au-OH. DFT calculations show that H(2)O(2) adsorption on Pt(110) results in the dissociation of O-O bond and the formation of Pt-OH bond. On Au, O-O bond elongation is calculated to occur only on the (110) face. However, the magnitude of the elongation is much smaller than that found on Pt(110).