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Facile synthesis of hierarchically nanostructured bismuth vanadate: An efficient photocatalyst for degradation and detection of hexavalent chromium
摘要： Heterostructured nanomaterials can paid more significant attention in environmental safety for the detection and degradation/removal of hazardous toxic chemicals over a decay. Here, we report the preparation of hierarchically nanostructured shuriken like bismuth vanadate (BiVO4) as a bifunctional catalyst for photocatalytic degradation and electrochemical detection of highly toxic hexavalent chromium (Cr(VI)) using the green deep eutectic solvent reline, which allows morphology control in one of the less energy-intensive routes. The SEM results showed a good dispersion of BiVO4 catalyst and the HR-TEM revealed an average particle size of ca. 5–10 nm. As a result, the BiVO4 exhibited good photocatalytic activity under UV-light about 95% reduction of Cr(VI) to Cr(III) was observed in 160 min. The recyclability of BiVO4 catalyst exhibited an appreciable reusability and stability of the catalyst towards the photocatalytic reduction of Cr(VI). Also, the BiVO4-modified screen printed carbon electrode (BiVO4/SPCE) displayed an excellent electrochemical performance towards the electrochemical detection of Cr(VI). Besides, the BiVO4/SPCE demonstrated tremendous electrocatalytic activity, lower linear range (0.01–264.5 μM), detection limit (0.0035 μM) and good storage stability towards the detection of Cr(VI). Importantly, the BiVO4 modified electrode was also found to be a good recovery in water samples for practical applications.
关键词： Shuriken-shaped BiVO4,Durable bifunctional catalyst,Deep eutectic green solvents,Photocatalytic Cr(VI) reduction,Electrochemical sensing
更新于2025-09-23 15:23:52
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Photodeposition of palladium nanoparticles on a porous gallium nitride electrode for nonenzymatic electrochemical sensing of glucose
摘要： A nonenzymatic electrochemical glucose sensor is described that was obtained by in situ photodeposition of high-density and uniformly distributed palladium nanoparticles (PdNPs) on a porous gallium nitride (PGaN) electrode. Cyclic voltammetric and chronoamperometric techniques were used to characterize the performance of the modified electrode toward glucose. In 0.1 M NaOH solution, it has two linear detection ranges, one from 1 μM to 1 mM, and another from 1 to 10 mM, and the detection limit is 1 μM. The electrode is repeatable, highly sensitive, fast and long-term stable. It was applied to the quantitation of serum glucose where it displayed accurate current responses.
关键词： Electrochemical sensing,Gallium nitride,Photodeposition,Glucose detection,Palladium nanoparticles,Porous materials
更新于2025-09-23 15:22:29
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Electrochemistry of Atomically Precise Metal Nanoclusters
摘要： Thiolate-protected metal nanoparticles containing a few to few hundred metal atoms are interesting materials exhibiting unique physicochemical properties. They encompass the bulk-to-molecule transition region, where discrete electronic states emerge and electronic band energetics yield to quantum con?nement e?ects. Recent progresses in the synthesis and characterization of ultrasmall gold nanoparticles have opened up new avenues for the isolation of extremely monodispersed nanoparticles with atomically precision. These nanoparticles are also called nanoclusters to distinguish them from other regular metal nanoparticles with core diameter >2 nm. These nanoclusters are typically identi?ed by their actual molecular formulas; prominent among these are Au25(SR)18, Au38(SR)24, and Au102(SR)44, where SR is organothiolate. A number of single crystal structures of these nanoclusters have been disclosed. Researchers have e?ectively utilized density functional theory (DFT) calculations to predict their atomic and electronic structures, as well as their physicochemical properties. The atomically precise metal nanoclusters have been the focus of recent studies owing to their novel size-speci?c electrochemical, optical, and catalytic properties. In this Account, we highlight recent advances in electrochemistry of atomically precise metal nanoclusters and their applications in electrocatalysis and electrochemical sensing. Compared with gold nanoclusters, much less progress has been made in the electrochemical studies of other metal nanoclusters, and thus, we mainly focus on the electrochemistry and electrochemical applications of gold-based nanoclusters. Voltammetry has been extremely powerful in investigating the electronic structure of metal nanoclusters, especially near HOMO and LUMO levels. A sizable opening of HOMO?LUMO gap observed for Au25(SR)18 gradually decreases with increasing nanocluster size, which is in line with the change in the optical gap. Heteroatom-doping has been a powerful strategy to modify the optical and electrochemical properties of metal nanoclusters at the atomic level. While the superatom theory predicts 8-electron con?guration for [Au25(SR)18]? and many doped nanoclusters thereof, Pt- and Pd-doped [PtAu24(SR)18]0 and [PdAu24(SR)18]0 nanoclusters show dramatically di?erent electronic structures, as manifested in their optical spectra and voltammograms, suggesting the occurrence of the Jahn?Teller distortion in these doped nanoclusters. Furthermore, metal-doping may alter their surface binding properties, as well as redox potentials. Metal nanoclusters o?er great potential for attaining high activity and selectivity in their electrocatalytic applications. The well-de?ned core?shell structure of a metal nanocluster is of special advantage because the core and shell can be independently engineered to exhibit suitable binding properties and redox potentials. We discuss recent progress made in electrocatalysis based upon metal nanoclusters tailored for water splitting, CO2 conversion, and electrochemical sensing. A well-de?ned model nanocatalyst is absolutely necessary to reveal the detailed mechanism of electrocatalysis and thereby to lead to the development of a new e?cient electrocatalyst. We envision that atomically controlled metal nanoclusters will enable us to systematically optimize the electrochemical and surface properties suitable for electrocatalysis, thus providing a powerful platform for the discovery of ?nely tuned nanocatalysts.
关键词： quantum con?nement,electrocatalysis,atomically precise metal nanoclusters,electrochemistry,electrochemical sensing
更新于2025-09-23 15:21:21
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Hierarchical Core-Shell Structure of 2D VS2@VC@N-Doped Carbon Sheets Decorated by Ultrafine Pd Nanoparticles: Assembled in 3D Rosette-like Array on Carbon Fiber Microelectrode for Electrochemical Sensing
摘要： The development of two-dimension (2D) nanohybrid materials with heterogeneous component in nanoscale and three-dimension (3D) well-ordered assembly in microscale has been regarded as an effective way to improve their overall performances by synergistic coupling of the optimized structure and composition. In this work, we reported the design and synthesis of a new type of hierarchically core-shell structure of 2D VS2@VC@N-doped carbon (NC) sheets decorated by ultrafine Pd nanoparticles (PdNPs), which were vertically grown on carbon fiber (CF) and assembled into a unique 3D rosette-like array. The resultant VS2@VC@NC-PdNPs modified CF microelectrode integrated the structural and electrochemical properties of the heterogeneous hybridization of core-shell VS2@VC@NC-PdNPs sheets with unique rosette-like array structure, and gave rise to a significant improvement in terms of electron transfer ability, electrocatalytic activity, stability and biocompatibility. Under the optimized conditions, the VS2@VC@NC-PdNPs modified CF microelectrode demonstrated excellent electrochemical sensing performance towards biomarker hydrogen peroxide (H2O2) including high sensitivity of 152.7 μA cm-2 mM-1, low detection limit of 50 nM (a signal-to-noise ratio of 3:1), as well as good reproducibility and anti-interference ability, which could be used for real-time in situ electrochemical detection of H2O2 in live cancer cells and cancer tissue. The remarkable performances of the proposed nanohybrid microelectrode will have a profound impact on the design of diverse 2D layered materials as promising candidate for electrochemical biosensing applications.
关键词： electrochemical sensing,hierarchical core-shell structure,three-dimension rosette-like sheets array,Two-dimension layered nanomaterials,cancer biomarker detection
更新于2025-09-23 15:19:57
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Graphene materials as a superior platform for advanced sensing strategies against gaseous ammonia
摘要： Ammonia (NH3) is an uncolored, toxic, corrosive, and reactive gas with a characteristic pungent stench. To date, quantitative analysis of NH3 concentrations have been made using conventional techniques (e.g., ion chromatography). In light of the complications involved in such applications, efforts have been made to develop detection methods of NH3 that are more sensitive and selective. In this respect, graphene-based sensors have attracted widespread attention because of graphene's distinctive electrical characteristics (e.g., low electrical signal noise and great mobility) and large surface area. This review article was designed to evaluate the potential usage of graphene-based gas sensors for effective detection of NH3. We aim to understand the recent advances in this challenging area of research by critically analyzing various experiments and comprehending their practical implications. This review critically compares the performance of graphene-based NH3 sensors with those of other nanomaterials for a broader understanding of the field. Also, we summarize the future prospects for advancement of graphene technology for NH3 sensing.
关键词： graphene,ammonia sensing,nanomaterials,electrochemical sensing,gas sensors
更新于2025-09-19 17:15:36
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Spectrophotometric, fluorimetric and electrochemical selective pyrophosphate/ATP sensing based on the dimethyltin(IV)-tiron system
摘要： Sensing of pyrophosphate anion (PPi) in the presence of nucleotide triphosphates allows the real time monitoring of the polymerase chain reaction. To get a deeper understanding of the factors involved in PPi/nucleotide triphosphate discrimination, a detailed study on the performance of a dimethyltin(IV)-catecholate complex capable of both separate fluorimetric or electrochemical detection of PPi in the presence of adenosine triphosphate (ATP) has been undertaken. Dimethyltin(IV) tightly binds PPi or ATP, and forms a stable 1:1 complex with tiron (4,5-dihydroxy-1,3-benzenedisulfonic acid) in water. The complexation equilibria with all components are characterized quantitatively by potentiometric and spectroscopic titrations. Pyrophosphate anion can be detected owing to its ability to release free tiron from the complex by measuring either a fluorimetric or an electrochemical signal. On the contrary, ATP does not displace tiron but causes an interference with PPi in the fluorimetric detection method due to the formation of a ternary Me2Sn(IV)-tiron-ATP complex with optical properties intermediate between those of free and bound tiron. In the electrochemical (square wave voltammetry) method, the ternary ATP complex shows a separate peak which does not coincide with the peaks of neither free nor bound tiron, thus making possible the simultaneous detection of ATP in addition to PPi.
关键词： optical sensing,dimethyltin(IV),pyrophosphate,electrochemical sensing,adenosine triphosphate selectivity,tiron
更新于2025-09-19 17:15:36
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[IEEE 2018 IEEE SENSORS - New Delhi, India (2018.10.28-2018.10.31)] 2018 IEEE SENSORS - C-MEMS Derived Glassy Carbon Electrodes as Sensitive Electrochemical Biosensors
摘要： Electrochemical biosensors have high potential for application in point of care setting, as they involve simpler measurements compared to optical counterparts and can operate in complex analyte. In this context, carbon electrodes have been widely explored since it is more stable than other metals. Pyrolyzed carbon electrodes have been deployed for protein sensing but the detection limit achieved is not satisfactory, probably due to the selection of the carbon precursor. In this paper, we have prepared glassy carbon electrodes using conventional carbon-microelectromechanical systems (C-MEMS) process. SU-8 photoresist has been used as the carbon precursor. The carbon thin film electrodes have then been tested by cyclic voltammetry measurements in the potential range of -800 mV to 800 mV in presence of 10 mM potassium ferricyanide solution. The samples have been immobilized with anti-Hep-B monoclonal antibody. The presence of antibodies has been further confirmed by UV-VIS spectrophotometry. It has been observed that the current peak reduces distinctly and the fractional change in current magnitude is around 30% and 83% at the potential of 175 mV for 1 fM and 1 pM concentrations respectively. Hence, the presented study is the proof-of concept of sensitive electrochemical detection of Hep-B using functionalized glassy carbon electrodes which when integrated with a low cost microfluidic platform can become suitable for point-of-care diagnostics.
关键词： biosensor,cyclic voltammetry,glassy carbon,C-MEMS,electrochemical sensing,Hep-B
更新于2025-09-19 17:15:36
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Raman Spectroscopy as an Assay to Disentangle Zinc Oxide Carbon Nanotube Composites for Optimized Uric Acid Detection
摘要： Refluxed zinc oxide (ZnO) nanoparticles (NPs) were prepared and attached to carboxylic acid functionalized multi-walled carbon nanotubes (COOH-MWNTs) via sonication. Practical optimization of electrocatalysts using sonication to disentangle a carbon nanotube composite for monitoring uric acid (UA) is shown. Monitoring UA is important for the management of medical disorders. Selection of sonication time is a crucial step in producing the desired composite. We report, for the first time, the practical use of Raman spectroscopy to tune the sonication involved in tethering ZnO NPs to the multi-walled carbon nanotube (MWNT) surface. Maximum current for detecting UA, using chronoamperometry and cyclic voltammetry, correlated with the highest sp2-hybridized carbon signal, as seen in the integrated Raman G band peak areas denoting maximum COOH-MWNT disentanglement. An array of ZnO/COOH-MWNT composites were prepared ranging from 60 to 240 min sonication times. Optimum sonication (150 min) corresponded with both maximum measured current and MWNT disentanglement. The sensor was able to quantitatively and selectively measure UA at clinically relevant concentrations (100–900 μM) with rapid current response time (< 5 s).
关键词： chronoamperometry,zinc oxide nanoparticles,Raman spectroscopy,cyclic voltammetry,multi-walled carbon nanotubes,electrochemical sensing
更新于2025-09-19 17:15:36
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[IEEE 2019 16th International Multi-Conference on Systems, Signals & Devices (SSD) - Istanbul, Turkey (2019.3.21-2019.3.24)] 2019 16th International Multi-Conference on Systems, Signals & Devices (SSD) - Investigation of Laser Induced Graphene Electrodes Modified by MWNT/AuNPs for Detection of Nitrite
摘要： In this paper, a novel low cost electrode material for sensing is presented which demonstrates excellent electrochemical response to nitrite while being amenable to implementation in disposable point of care nitrite sensors. Laser induced grapheneous carbon (LIG) is based on a simple laser engraving method to fabricate electrodes by inducing conductive paths onto Kapton polymer substrate. The working electrode was modified by Gold Nanoparticles (AuNPs), multiwalled carbon nanotubes (MWCNT) and AuNPs/MWCNT. The modified electrodes were characterized by electron microscopy energy x-ray dispersive spectroscopy (SEM-EDX), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Surface morphology and electrochemical methods confirms confirm the successful implementation of LIG electrodes whose electrocatalytic performance is highly improved after modification. This suggests the synergetic effect between AuNPs and MWCNTs with the excellent conductivity and large specific surface area. By means of square wave voltammetry (SWV), the limit of detection of the proposed sensor is 6.75 μM, which is low enough for practical applications. In conclusion, AuNPs/MWCNT modified LIG electrodes demonstrated good electrochemical behavior and promising future use in disposable nitrite electrochemical sensors.
关键词： electrochemical sensing,nitrite detection,carbon nanotubes,gold nanoparticles,Laser induced graphene
更新于2025-09-16 10:30:52
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Conjugated polymer self-assembled with graphene: Synthesis and electrochemical 1-hydroxypyrene sensor
摘要： Urinary 1-hydroxypyrene (1-OHP), one of the metabolite of polycyclic aromatic hydrocarbons (PAHs), has been extensively applied as a biomarker of animals and human exposure to PAHs. Herein, we synthesized a novel conjugated polymer poly-8-methoxy-7-methyl-5-(10-anthracen-9-yl)quinolone (PMMAYQ) using Suzuki coupling reaction, and then fabricated a homogeneous PMMAYQ/grahene multilayer film via layer-by-layer self-assembly technique and applied for electrochemical sensing of 1-OHP. Under the optimal conditions, {PMMAYQ-Graphene}16 modified glass carbon electrode exhibited excellent response for detection of 1-OHP. A linear range from 0.5 to 120 nM was obtained with a low detection limit of 0.07 nM (S/N=3) and a sensitivity of 0.5539 μA/μM. The electrochemical sensor exhibited excellent stability, accepted repeatability, and good selectivity. The developed method was employed for determination of 1-OHP in human urine samples and recoveries in the range of 95.6%?107.1% were achieved.
关键词： Self-assembly,Electrochemical sensing,Graphene,1-hydroxypyrene,Conjugated polymer
更新于2025-09-16 10:30:52