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NO 2 – detection based on Au-Ni-Rh/LIG electrochemical sensor. [Display omitted] • Au, NiO, and Rh nanoparticles were deposited onto LIG by one-step electrodeposition. • DFT calculation confirmed the enhanced adsorption energy and electron transfer. • Three metals promoted the detection of nitrite in terms of catalysis and adsorption. • The developed sensor obtained a very low detection limit of 0.3 μM for nitrite. • This sensor can be used for portable determination of NO 2 – in real water samples. In this study, we employed a straightforward and rapid one-step electrodeposition method to enhance modify an Au/NiO/Rh composite on laser-induced graphene (LIG) for nitrite (NO 2 –) detection. We extensively characterized and tested the morphological composition and electrochemical properties of the electrode using scanning electron microscopy and other characterization techniques. To compare the electrochemical active surface areas of the electrode before and after modification, we conducted cyclic voltammetry experiments. Additionally, we confirmed the changes in electron transfer performance and adsorption energy of the modified electrode through by density functional theory calculations. The experimental results demonstrate that the combined modification of LIG with rhodium nanoparticles (RhNPs) and gold nanoparticles (AuNPs) improves electron transport ability at the electrode interface and enhances the electrode's electrocatalytic performance. The incorporation of nickel oxide (NiO) also provides a larger reaction area and more active sites for NO 2 – detection. The synergistic effects of these three modified components significantly enhance NO 2 – detection at the electrode, surpassing the performance of the bimetallic modified electrode. Under optimized experimental conditions, the sensor exhibits a linear range of 1 μmol/L to 1 mmol/L and a detection limit of 0.3 μmol/L. Furthermore, the sensor demonstrates excellent anti-interference and repeatability properties. We successfully applied the sensor for determination of NO 2 – in tap water, yielding satisfactory results. This research presents a promising strategy for the portable, sensitive, and in-situ detection of NO 2 – in water environments using metal-based electrochemical sensors. [ABSTRACT FROM AUTHOR]

OFL detection based on β-CD/Sm 2 O 3 NPs/LIG electrochemical sensor. [Display omitted] • Sm 2 O 3 nanoparticles and β-CD were firstly used to modified graphene electrode. • The synergistic effect of two modification compositions promoted OFL detection. • DFT calculation confirmed the enhanced adsorption energy and electron transfer. • The developed sensor obtained a very low detection limit of 0.005 μM for OFL. We developed a new electrochemical sensor that detects ofloxacin (OFL) in water by depositing β-cyclodextrin (β-CD) and samarium oxide nanoparticles (Sm 2 O 3 NPs) onto a laser-induced graphene (LIG) electrode. Scanning electron microscopy, Transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, contact angle measurements, and electrochemical impedance spectroscopy were used to characterize β-CD/Sm 2 O 3 NPs/LIG electrodes. Our results showed that the improved electrochemical activity is due to the excellent electrocatalytic performance of Sm 2 O 3 NPs, improving electron transfer efficiency. The deposition of β-CD improves electrode hydrophilicity and increases the adsorption capacity of OFL on the electrode surface. The synergistic effect of two modification compositions can promote OFL detection. The enhanced adsorption energy and improved electron transfer characteristics were also confirmed by density functional theory calculations. Under optimal detection conditions, the sensor achieves a wide linear range (0.01 ∼ 1.0 μmol/L and 1.0 ∼ 120 μmol/L) and a low detection limit (0.005 μmol/L) with good anti-interference ability and stability. This sensor has also been successfully applied to the detection of OFL in tap water and lake water. These results show that the developed sensor is a promising step towards rapid in situ detection of OFL in water environments. [ABSTRACT FROM AUTHOR]

The surface modification of GCE promoted ion adsorption and electron transfer, so as to sensitively detect Cd(Ⅱ) ions. [Display omitted] • g-C 3 N 4 and SnO 2 nanoparticles were firstly used to modified glassy carbon electrode. • The synergistic effect of two modification compositions promoted Cd(II) ions detection. • The developed sensor obtained a very low detection limit of 0.16 μg L−1 for Cd(II) ions. In this work, we developed a novel electrochemical sensor modified with graphitic carbon nitride (g-C 3 N 4) and tin dioxide nanoparticles (SnO 2 NPs). The detection of Cd(II) ion in water environments was carried out using differential pulse anodic stripping voltammetry (DPASV) technique. Scanning electron microscopy, X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy, and contact angle analyses were used for electrode characterization. The experimental results show that the improved electrochemical activity is due to the large specific surface area and hydrophilic functional groups of g-C 3 N 4 , which improves the hydrophilicity of the electrode and the adsorption of Cd(II) ions. Meanwhile, SnO 2 has excellent electrocatalytic performance, which enhances the free electron transfer efficiency. The combination of these two modified compositions can synergistically improve the electrode sensitivity, and enhance the response speed of the detection process. Under the optimal detection conditions, the sensor achieves a wide linear range (0.05–100 μg L−1) and a lower detection limit (0.16 μg L−1), with good anti-interference performance and stability. This sensor has also been successfully applied to detect Cd(II) ions in tap water and groundwater. Our findings provide a promising method for sensitive, rapid, and in situ monitoring of Cd(II) ions in aqueous environments. [ABSTRACT FROM AUTHOR]

The rapid detection of rare earth elements is crucial in various fields, such as materials science, biomedicine, and water quality assessment. However, no studies have reported on the detection of yttrium (Y) using electrochemical sensor-based devices. In this study, we present an innovative method for detecting Y(III) ions in aquatic environments using an electroanalytical detection platform. We have developed a complexation catalytic method that integrates trans-1,2-cyclohexanediaminetetraacetic acid (CyDTA) and silver nanoparticles (Ag NPs), thereby enhancing the adsorption and electrochemical response of Y(III) ions. The modified electrode demonstrates an 18-fold increase in the response signal of the Y(III) reduction peak compared to the bare LIG electrode. To elucidate the electrocatalytic mechanism, we conducted various interface characterization methods and DFT simulations. The Ag-CyDTA/LIG electrode exhibits excellent detection performance, with a broad linear dynamic range of 1 × 10−6 to 0.01 g/L and an exceptionally low detection limit of 0.02 μg/L. Significantly, we successfully employed the electrochemical sensing platform to analyze real water samples from rare earth ore, marking the first report on the voltammetric detection of Y(III) ions in real water samples using a flexible electrode. These findings offer a promising technical solution for the practical detection of Y(III) ions. [Display omitted] • Ag NPs and CyDTA firstly modified laser-induced graphene electrodes. • The peak current of Y(III) ions on modified electrode increased 18-fold. • DFT calculations verified the altered adsorption and electron behavior. • The sensor was applied to real water samples from rare earth mining site. [ABSTRACT FROM AUTHOR]

A novel electrochemical sensor was constructed based on modification of polyaniline (PANI) and graphitic-phase carbon nitride (g-C 3 N 4) composites. Detection of Cd(II) ions in the aqueous environment using differential pulsed anodic stripping voltammetry (DPASV) technique. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), contact angle (CA), and Tafel curve analyses were used to characterize the physical and electrochemical properties of electrode. We prepared a new PANI@g-C 3 N 4 composite material by combining the two substances based on their respective advantages. The composite material was applied to electrode detection for the first time, which significantly enhanced the transfer of free electrons on the surface of the electrode, improved the sensitivity of the electrode, increased the adsorption capacity of Cd ions, and significantly improved the detection effect of the electrode. Parameters such as the amount of PANI@g-C 3 N 4 modification, deposition potential, deposition time and solution pH were optimized to determine the best conditions for the detection of Cd(II) ions. Under optimal conditions, our sensor achieves a best signal at −0.78 V (vs. Ag/Agcl electrode), and exhibits a wide linear concentration range of 0.1–140 μg/L with a low detection limit of 0.05 μg/L. The sensor was successful in implementing the identification of real water samples with recoveries ranging from 91 % to 106 %. The relative standard deviation (RSD) is less than 4.31 %. Besides, the sensor has outstanding anti-interference, repeatability and steadiness. The successful application of this sensor provides a new idea for efficient detection of Cd(II) ions in aquatic environments. [Display omitted] • PANI and g-C 3 N 4 composites were firstly used to modify GCE for Cd(II) detection. • The composite improves the electrode conductivity and Cd adsorption performance. • The PANI@g-C 3 N 4 @GCE shows a low Cd detection limit with wide linear range. • This sensor was also applied to the detection of Cd(II) ions in real water samples [ABSTRACT FROM AUTHOR]

[Display omitted] • AuNPs and Gly-C modified flexible LIG electrode was firstly develop. • AuNPs and Gly-C synergistically promoted the electrochemical performance. • The fabricated Gly-C/Au/LIG sensor achieves a low nitrite detection limit. • This sensor was successfully applied to detection of nitrite in real water samples. In this work, we firstly developed a laser-induced graphene (LIG) electrode modified by gold nanoparticles (AuNPs) and glycine-modified nanocarbon (Gly-C), and used it to detect nitrite by linear scanning voltammetry. The physical and electrochemical characteristics of the electrodes were characterized using scanning electron microscopy, energy dispersive spectroscopy analysis, fourier transform infrared spectroscopy, and contact angle analysis. Our findings demonstrated that the electrocatalytic oxidation of nitrite can be enhanced by the successful loading of AuNPs, and Gly-C enhances electrode hydrophilicity and promotes nitrite adsorption capacity of the electrode surface. Under optimal conditions, the linear of the sensor is 7 ∼ 700 μg/L and 700 ∼ 1050 μg/L, and the detection limit is 0.84 μg/L. The anti-interference, repeatability, and stability of this sensor are outstanding. Recovery rates of the sensor in the actual groundwater and tap water varied from 94 to 123 %, and the relative standard deviation was less than 6.06 %. Our findings offer a potentially effective method for on-site monitoring of nitrite in aquatic environments. [ABSTRACT FROM AUTHOR]

Since lead is teratogenic, carcinogenic and mutagenic, people pay increasing attention to lead contamination in water environment. In this work, a novel electrochemical sensor was developed to detect Pb(II) ion in water by PPy, MOFs and bismuth film (BF) modify GCE. Scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, electrochemical impedance spectroscopy, contact angleanalyses, cyclic voltammetry and differential pulse anodic stripping voltammetry were used to characterize the BF-PPy/UIO-66-NH 2 /GCE surface, revealing the physical and electrochemical properties of the electrode. MOFs increased the specific surface area and adsorption site of the electrode. The PPy enhanced the conductivity of the composites materials. MOFs and PPy synergistically promoted the electrochemical performance of the electrode. The deposition potential, deposition time, solution pH and Bi (III) concentration were optimized to determine the optimal detection condition. The electrode has a wide linear range (0.5 to 10 μg/L) with a low detection limit (0.05 μg/L). This electrode also has good anti-interference, repeatability and stability. Besides, it has been successfully applied to the detection of actual water samples. The recovery rates ranged from 95.4 % to 102.8 % with a relative standard deviation (RSD) less than 4.40 %. Our results provide an insight on efficient and rapid detection of Pb(II) ions in water environment in the future. [Display omitted] • MOFs and polypyrrole synergistically promoted the electrochemical performance. • The fabricated BF-PPy/UIO-66-NH 2 /GCE shows a low Pb(II) detection limit. • This sensor was applied to the detection of Pb(II) in tap water and groundwater. [ABSTRACT FROM AUTHOR]