Search

l -cysteine (L-Cys) plays an important role in human health as well as in the biological environment. Here, a simple physical mixing technique was used to create the p-n heterojunction by homogeneously immobilizing cuprous oxide/copper@microporous carbon (Cu 2 O/Cu@mC) on the surface of a sheet of g-C 3 N 4 (CNS). Among them, the porous structure of Cu 2 O/Cu@mC after heat treatment is favorable for charge storage. Meanwhile, the carbon element in Cu 2 O/Cu@mC acts as a photosensitizer and electron mediator to extend visible light absorption. Compared with bulk g-C 3 N 4 (CNB), the sheet-like structure and high specific surface area of CNS can be used as a carrier for the binding of Cu 2 O/Cu@mC with L-Cys. Based on the interaction between L-Cys and Cu 2 O/Cu@mC through the formation of Cu–S bonds, Cu 2 O/Cu@mC/CNS was proposed as a light-driven enzyme-free photoelectrochemical sensor for the detection of L-Cys. In the best case, the Cu 2 O/Cu@mC/GCE sensor has a low limit of detection of 1.26 × 10−9 M for L-Cys and a wide linear range (1.0 × 10−8 M − 4.0 × 10−6 M). The repeatability, reproducibility, stability, selectivity and specificity of the sensor were satisfactory. In addition, the potential applicability of the proposed photoelectrochemical sensor was evaluated in tap water and human serum. [Display omitted] • A low-cost and simple method to detect L-Cys in tap water and human serum. • The Cu 2 O/Cu@mC/CNS has excellent chemical stability and high selectivity. • It is a highly sensitive enzyme-free PEC sensor composed of p-n heterostructure. • The constructed PEC sensor has an ultra-low LOD and an ultra-wide linear range. [ABSTRACT FROM AUTHOR]

[Display omitted] • The cauliflower-like CdS with the rough and wide surface was created. • The CdS/rGO@Au/GCE sensor has wide linear range (5 nM − 4 μM). • The detection limit of 2.88 nM is 10,000-fold lower than the WHO guideline. • The sensor has been used to analyze Cu(II) in pool water with great performance. • Material-target interaction is used to solve the selectivity problem of PEC sensors. Copper (II) ion (Cu2+) is a typical heavy metal ion that not only harms the soil and water environment, but also causes neurological disorders, liver cirrhosis and other diseases. Here, we have successfully synthesized three-dimensional CdS/rGO@Au heterojunction using a simple physical mixing technique, characterized the material synthesis by X-ray diffraction spectroscopy (XRD), Transmission electron microscopy (TEM), and finally used it for selective photoelectrochemical detection of Cu2+. In this system, the synergistic interaction of the three creates a channel that is ideal for charge carrier separation and transfer. The cauliflower-shaped CdS possesses a large surface area and acts as a Cu2+ probe. rGO@Au acts as a sensitizer and amplifies the current change. The photocurrent of the CdS/rGO@Au heterojunction is 7 times higher than that of CdS, indicating that CdS/rGO@Au has a good photoresponse intensity. Under the optimized detection conditions, the proposed photoelectrochemical sensor was able to detect Cu2+ concentration in the range of 5 nM to 4 μM with a very low limit of detection (LOD) of 2.88 nM. Moreover, the application feasibility of the developed CdS/rGO@Au heterojunction sensor was verified by the detection of Cu2+ in real water samples. [ABSTRACT FROM AUTHOR]

• The MoO 3 -PEDOT nanomaterials were prepared by in-situ growth method. • CD-MOF was electrodeposited on the MoO 3 -PEDOT/GCE to form a luteolin electrochemical sensor with outstanding performances. • The sensor was successfully applied for detecting luteolin in both homemade and commercial chrysanthemum tea. Chrysanthemum tea is a tranditional Chinese health drink, which contains luteolin, a flavonoid with vesatile health benefit activities. Herein, A sensitive electrochemical sensor based on composite materials consisting of MoO 3 nanorods, poly (3, 4-ethylene dioxyethiophene)(PEDOT), and γ -cyclodextrin metal–organic framework(CD-MOF) was prepared.The materials were characterized and analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS). Due to the synergistic effects of the materials, the sensor showed a wide linear range of 0.4 nM −1800 nM and a low detection limit (LOD) of 0.1 nM (S/N = 3) for luteolin under optimized conditions. Besides, the influences of some coexistent phenolic compounds and common metal ions on luteolin detection were evaluated and no significant interference was observed. Finally, the sensor was successfully applied to the detection of luteolin in real Chrysanthemum tea samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • A low cost and simple method for the detection of gallic acid in food. • The g-C 3 N 4 @CNT has good chemical stability and non-toxicity. • This is a covalently bonded "signal-on" high-sensitivity non-enzyme PEC sensor. • The constructed PEC sensor has an ultra-low LOD and a wide linear range. • This is first PEC sensor based on g-C 3 N 4 @CNT heterojunction to detect gallic acid. Gallic acid (GA) is found in a wide range of natural plants and is relevant to the health of human beings. Here, a photoelectrochemical sensing platform based on g-C 3 N 4 @CNT heterojunction has been prepared for the highly sensitive and selective detection of GA. Under the light of xenon lamp, the photocurrent of g-C 3 N 4 @CNT is 7 times higher than that of g-C 3 N 4. And the sensor generates 4 times more photocurrent in the presence of GA than without GA. This sensor has a wide linear range from 10 nM to 10 μM with a limit of detection as low as 2 nM. Also, the abundant amino groups of g-C 3 N 4 provide excellent selectivity for the sensor. Furthermore, the sensor can be used for the analysis of GA in black tea samples, which provides a novel and rapid method for the detection of GA in food samples. [ABSTRACT FROM AUTHOR]

To achieve large-scale development of triboelectric nanogenerators (TENGs) for water wave energy harvesting and powering the colossal sensors widely distributed in the ocean, facile and scalable TENGs with high output are urgently required. Here, an elastic self-recovering hybrid nanogenerator (ES-HNG) is proposed for water wave energy harvesting and marine environmental monitoring. The elastic skeletal support of the ES-HNG is manufactured using three-dimensional (3D) printing technology, which is more conducive to the large-scale integration of the ES-HNG. Moreover, the combination of a TENG and an electromagnetic generator (EMG) optimizes the utilization of device space, leading to enhanced energy harvesting efficiency. Experimental results demonstrate that the TENG achieves a peak power output of 42.68 mW, and the EMG reaches a peak power output of 4.40 mW. Furthermore, various marine environment monitoring sensors, such as a self-powered wireless meteorological monitoring system, a wireless alarm system, and a water quality monitoring pen, have been successfully powered by the sophisticated ES-HNG. This work introduces an ES-HNG for water wave energy harvesting, which demonstrates potential in marine environment monitoring and offers a new solution for the sustainable development of the marine internet of things. [ABSTRACT FROM AUTHOR]

[Display omitted] • The flower-like A-ZnWO 4 /C composite material synthesized by ZIF-8 was reported. • Kaempferol electrochemical sensor based on A-ZnWO 4 /C was constructed for the first time. • A-ZnWO 4 /C/GCE showed ultra-sensitive detection towards kaempferol. • The method was successfully applied for analysis of kaempferol in natural samples. Kaempferol (KA), an important polyphenolic compound, is able to combat a variety of inflammatory diseases. Here, a ZnWO 4 / porous nanocarbon based electrochemical sensor has been constructed to detect KA for the first time. Innovatively, ZnWO 4 has been synthesized by pyrolysis using ZIF-8 as a zinc source, while porous nanocarbon was introduced. The nanocomposites have been characterized by X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy and demonstrated that Acidified ZnWO 4 /porous nanocarbon has been successfully prepared. Notably, the excellent catalytic properties of ZnWO 4 and the great enrichment ability and conductivity of porous nanocarbon greatly enhanced the detection performance of the sensor for KA with a linear range of 0.009–0.7 μM and a LOD of 2.03 nM. In addition, the sensor has obtained satisfactory results for the detection of KA in actual natural samples (broccoli and kaempferia powder). The reaction sites and redox mechanism of KA were shown by density functional theory. Finally, the sensor is highly sensitive and stable, making it a novel detection method with extremely high potential applications. [ABSTRACT FROM AUTHOR]

Temperature-controlled "On-Off" electrochemical behavior of hydroquinone at rGO@Au/PNVCL/m-BiVO 4 /GCE. [Display omitted] • A temperature-controlled electrochemical sensor for hydroquinone is constructed with good stability and reversibility. • The electrochemical sensor based on the composite exhibites electrochemical performance for HQ. • This sensor has wide linear detection range with low LOD of 0.6 μM. • The sensor has good stability and accurate characterization for detection in real samples. In this paper, a temperature-controlled "On-Off" electrochemical sensor for the detection of hydroquinone (HQ) is constructed by using a composite film of temperature-sensitive polymer poly (N-vinylcaprolactam) (PNVCL), the nanomaterial rGO@Au and the monoclinic bismuth metavanadate (m-BiVO 4). The sensor exhibits good temperature sensitivity and reversibility. When the temperature drops below the Lowest Critical Solution Temperature (LCST) of the PNVCL, the PNVCL will be in a "stretched" state, which hinders the electron exchange between hydroquinone and the surface of the electrode, presenting an "Off" state for the sensor. On the contrary, when the temperature exceeds the LCST, the PNVCL will be in a "contracted" state, which hydroquinone can perform an effective redox process and generate a response current, showing an "On" status. Due to the good electroconductivity and electrocatalytic ability of rGO@Au and m-BiVO 4 , the proposed sensor showed excellent detection performances. Hence, the sensor shows wide linear ranges (2.0 to 30.0 μM and 30.0 to 152.0 μM) and low limit of detection (0.6 μM). In addition, the "On-Off" electrochemical sensor may provide new ideas for the application of intelligent polymers. [ABSTRACT FROM AUTHOR]

• A friendly strategy for fabricating Pd particles on MWCNTs supported catalyst. • The reaction condition was optimized (7 h, n NaBH4/Pd = 10, pH = 9, 170 ℃). • The catalyst Pd/CNTs-D170 has the larger ECSA was attribute to smaller particle. • The Pd/CNTs-D170 shows higher electrocatalytic performance for formic acid. It remains a major challenge to enhance the activity of Pd catalyst and meanwhile minimize the CO poisoning due to adsorbed CO during formic acid oxidation (FAO). Herein, highly dispersed Pd on multi-walled carbon nanotubes (MWCNTs) supported catalysts were prepared in a non-aqueous deep eutectic solvent (DES) system. The catalyst prepared at 170 °C (referred to Pd/CNTs-D170) showed higher catalytic performance toward FAO (peak current: 1712.6 mA mg Pd −1) and better CO anti-poisoning capability (onset potential: 0.59 V, peak potential: 0.69 V) than the Pd/CNTs-W (synthesized in water) (1130.9 mA mg Pd −1, 0.65 V, 0.71 V) and commercial Pd/C (555.8 mA mg Pd −1, 0.66 V, 0.74 V) catalysts. This study provides a suitable strategy for the preparation of high-performance Pd-based electrocatalysts for direct formic acid fuel cell (DFAFC). [ABSTRACT FROM AUTHOR]