| 1. |
- Gao, Sanshuang, et al.
(författare)
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Selective voltammetric determination of Cd(II) by using N,S-codoped porous carbon nanofibers
- 2018
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Ingår i: Microchimica Acta. - : Springer. - 0026-3672 .- 1436-5073. ; 185
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Tidskriftsartikel (refereegranskat)abstract
- Porous carbon nanofibers codoped with nitrogen and sulfur (NFs) were prepared by pyrolysis of trithiocyanuric acid, silica nanospheres and polyacrylonitrile (PAN) followed by electrospinning. The NFs were used to modify a glassy carbon electrode (GCE) which then displayed highly sensitive response to traces of Cd(II). Compared to a bare GCE and a Nafion modified GCE, the GCE modified with codoped NFs shows improved sensitivity for Cd(II) in differential pulse anodic sweep voltammetry. The stripping peak current (typically measured at 0.81 V vs. Ag/AgCl) increases linearly in the 2.0–500 μg·L−1 Cd(II) concentration range. This is attributed to the large surface area (109 m2·g−1), porous structure, and high fraction of heteroatoms (19 at.% of N and 0.75 at.% of S). The method was applied to the determination of Cd(II) in (spiked) tap water where it gave recoveries that ranged between 96% and 103%.
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| 2. |
- Gao, Sanshuang, et al.
(författare)
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Sensitive and Selective Differential Pulse Voltammetry Detection of Cd(II) and Pb(II) Using Nitrogen-Doped Porous Carbon Nanofiber Film Electrode
- 2017
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Ingår i: Journal of the Electrochemical Society. - : Electrochemical Society. - 0013-4651 .- 1945-7111. ; 164:13, s. H967-H974
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Tidskriftsartikel (refereegranskat)abstract
- Carbon matrix materials are regarded as one of the most important electrode materials for heavy metal detection. But even so, optimization procedures of carbon nanofibers (CNFs) for tracing Cd(II) and Pb(II) remains challenging. Here, zeolitic imidazolate framework (ZIF-8)/polyacrylonitrile (PAN)-derived nitrogen-doped porous carbon nanofibers (N-PCNFs) were investigated as a new electrode material for determining the concentration of Cd(II) and Pb(II). By optimizing electrochemical conditions such as deposition potential, deposition time, pH of buffer solution, and quantity of N-PCNFs loaded on a glassy carbon electrode (GCE), the linear response curves of Cd(II) and Pb(II) could be obtained. Due to the unique structural feature and N content, the N-PCNFs possess excellent detection limits of 0.8 mu g L-1 for Cd(II) and 0.3 mu g L-1 for Pb(II) (S/N = 3). To manifest the practical use of the sensor platform the concentration of Cd(II) and Pb(II) in normal tap and waste water were monitored. According to the ICP-MS results, the calculated recovery (97.0-107%) indicates that N-PCNFs have potential as a candidate material to monitor the concentration of Cd(II) and Pb(II) in practical samples.
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| 3. |
- Jiang, Ruyuan, et al.
(författare)
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A Facile Electrochemical Sensor Based on PyTS-CNTs for Simultaneous Determination of Cadmium and Lead Ions
- 2018
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Ingår i: Sensors. - : MDPI. - 1424-8220. ; 18:5
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Tidskriftsartikel (refereegranskat)abstract
- A simple and easy method was implemented for the contemporary detection of cadmium (Cd2+) and lead (Pb2+) ions using 1,3,6,8-pyrenetetrasulfonic acid sodium salt-functionalized carbon nanotubes nanocomposites (PyTS-CNTs). The morphology and composition of the obtained PyTS-CNTs were characterized using scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and X-ray photoelectron spectroscopy (XPS). The experimental results confirmed that the fabricated PyTS-CNTs exhibited good selectivity and sensitivity for metal ion-sensing owing to the insertion of sulfonic acid groups. For Cd2+ and Pb2+, some of the electrochemical sensing parameters were evaluated by varying data such as the PyTS-CNT quantity loaded on the pyrolytic graphite electrode (PGE), pH of the acetate buffer, deposition time, and deposition potential. These parameters were optimized with differential pulse anodic sweeping voltammetry (DPASV). Under the optimal condition, the stripping peak current of the PyTS-CNTs/Nafion/PGE varies linearly with the heavy metal ion concentration, ranging from 1.0 mu g L-1 to 90 mu g L-1 for Cd2+ and from 1.0 mu g L-1 to 110 mu g L-1 for Pb2+. The limits of detection were estimated to be approximately 0.8 mu g L-1 for Cd2+ and 0.02 mu g L-1 for Pb2+. The proposed PyTS CNTs/Nafion/PGE can be used as a rapid, simple, and controllable electrochemical sensor for the determination of toxic Cd2+ and Pb2+.
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| 4. |
- Jiang, Ruyuan, et al.
(författare)
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Polysulfide/Graphene Nanocomposite Film for Simultaneous Electrochemical Determination of Cadmium and Lead Ions
- 2018
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Ingår i: NANO. - : World Scientific. - 1793-2920 .- 1793-7094. ; 13:8
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Tidskriftsartikel (refereegranskat)abstract
- An integrative electroanalytical method was developed for detecting Cd2+ and Pb2+ ions in aqueous solutions. Polysulfide/graphene (RGO-S) nanocomposites were prepared and their performance as electrochemical sensors for Cd2+ and Pb2+ was evaluated. The RGO-S nanocomposite was carefully characterized by scanning electron microscopy with energy-dispersive X-ray spectrometry, transmission electron microscopy, and X-ray photoelectron spectroscopy. The as-prepared RGO-S was incorporated into a pyrolytic graphite electrode (RGO-S/PGE) and used for detecting trace amount of Cd2+ and Pb2+ by differential pulse anodic stripping voltammetry. Under optimal conditions, the stripping peak current of RGO-S/PGE varies linearly with heavy metal ion concentration in the ranges 2.0-300 mu g L-1 for Cd2+ and 1.0-300 mu g L-1 for Pb2+. The limits of detection for Cd2+ and Pb2+ were estimated to be about 0.67 mu g L-1 and 0.17 mu g L-1, respectively. The prepared electrochemical heavy-metal-detecting electrode provides good repeatability and reproducibility with high sensitivity, making it a suitable candidate for monitoring Cd2+ and Pb2+ concentrations in aqueous environmental samples.
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| 5. |
- Qin, Danfeng, et al.
(författare)
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N-Doped Hollow Porous Carbon Spheres/Bismuth Hybrid Film Modified Electrodes for Sensitive Voltammetric Determination of Trace Cadmium
- 2018
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Ingår i: Electroanalysis. - : Wiley-VCH Verlagsgesellschaft. - 1040-0397 .- 1521-4109. ; 30:9, s. 1906-1912
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Tidskriftsartikel (refereegranskat)abstract
- In this work, N-doped hollow porous carbon spheres (N-HPCSs) were synthesized by silicon dioxide template-assisted polybenzoxazine (PB) coating strategy. The prepared N-HPCSs have a smooth hollow ball structure surrounded by a well-defined porous shell. Combining with in-situ plating of Bi film, the N-HPCSs were further fabricated a sensitive electrochemical platform for determination trace levels of Cd(II) by differential pulse anodic stripping voltammetry (DPASV). Under the optimized conditions, the Bi-N-HPCSs based sensor displays a linear response to Cd(II) over the range of 0.5gL(-1) to 150gL(-1). Meanwhile, the limit of detection (LOD, S/N=3) is estimated to be around 0.16gL(-1) for Cd(II), which is 31 times lower than the safety values set by United States Environmental Protection Agency (EPA) for the drinking water. Moreover, the proposed method was successfully applied to detection of Cd(II) in tap water and lake water, and the analytical results of the presented method are agreed well with inductively coupled plasma-mass spectrometry (ICP-MS) data. Due to the excellent analytical performance, the fabricated electrode is promised for future development in monitoring of cadmium pollution in the environment.
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| 6. |
- Shen, Hangjia, et al.
(författare)
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Microwave-assisted synthesis of multimetal oxygen-evolving catalysts
- 2017
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Ingår i: Electrochemistry communications. - : Elsevier. - 1388-2481 .- 1873-1902. ; 81, s. 116-119
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Tidskriftsartikel (refereegranskat)abstract
- Oxygen evolution reaction (OER) plays a pivotal role in water-splitting. Here, we report a facile method to synthesize multimetal supported on commercial carbon black via a time-saving microwave process. Crystalline FeNi3 nanoparticles homogeneously doped with Mo are formed via a microwave treatment and activated to metal oxyhydroxide in-situ during cyclic voltammetry test with overpotential of only 280 mV at 10 mA cm(-2) for OER in alkaline electrolyte, outperforming RuO2. Our synthesis methodology is a promising alternative for large-scale production, delivering a valuable contribution to catalyst preparation and electrocatalytic water oxidation research.
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| 7. |
- Shen, Hangjia, et al.
(författare)
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Synergistic Effects between Atomically Dispersed Fe-N-C and C-S-C for the Oxygen Reduction Reaction in Acidic Media
- 2017
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Ingår i: Angewandte Chemie International Edition. - : John Wiley & Sons. - 1433-7851 .- 1521-3773. ; 56:44, s. 13800-13804
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Tidskriftsartikel (refereegranskat)abstract
- Various advanced catalysts based on sulfur-doped Fe/N/C materials have recently been designed for the oxygen reduction reaction (ORR); however, the enhanced activity is still controversial and usually attributed to differences in the surface area, improved conductivity, or uncertain synergistic effects. Herein, a sulfur-doped Fe/N/C catalyst (denoted as Fe/SNC) was obtained by a template-sacrificing method. The incorporated sulfur gives a thiophene-like structure (C-S-C), reduces the electron localization around the Fe centers, improves the interaction with oxygenated species, and therefore facilitates the complete 4e- ORR in acidic solution. Owing to these synergistic effects, the Fe/SNC catalyst exhibits much better ORR activity than the sulfur-free variant (Fe/NC) in 0.5m H2SO4.
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| 8. |
- Sukhrobov, Parviz, et al.
(författare)
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Nonenzymatic Glucose Biosensor Based on NiNPs/Nafion/Graphene Film for Direct Glucose Determination in Human Serum
- 2018
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Ingår i: NANO. - 1793-2920 .- 1793-7094. ; 13:7
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Tidskriftsartikel (refereegranskat)abstract
- This study describes a type of novel nickel nanoparticles (NiNPs) decorated on Nafiongraphene composite film by using the electrochemical deposition method. It was used to fabricate electrochemical biosensors for sensitive nonenzymatic glucose detection. Compared with the Nafion-graphene film and NiNPs-modified glassy carbon electrode (NiNPs-GCE), the NiNPs/Nafion/graphene/GCE showed the best electrocatalytic activity towards glucose oxidation in alkaline medium. The NiNPs/Nafion/graphene/GCE at an applied potential of +0.55 V in a linear range of 1-200 mu M presented a high sensitivity of 3437.25 mu A center dot mM(-1) cm(-2) with coefficient of correlation R-2 = 0.999; and in a linear range of 200-10800 mu M it performed the best sensitivity of 2848.6 mu A center dot mM(-1) cm(-2) with coefficient of correlation R-2 = 0.995 towards glucose oxidation. For a concentration up to 200 mu M, a linear range was obtained with a limit of detection of 0.6 mu M (signal to noise = 3) and as much as 10 800 mu M with a limit of detection of 0.82 mu M (signal to noise = 3). The time of responses was about 1-1.5 s with the addition of 0.1-1 mM glucose. In addition, NiNPs/Nafion/graphene/GCE also has a high anti-interference ability toward common oxidative interfering species, such as uric acid, ascorbic acid and dopamine. More importantly, NiNPs/Nafion/graphene/GCE was successfully used for the determination of glucose concentration in human serum samples in comparison with a local hospital. The NiNPs/Nafion/graphene/GCE exhibited high sensitivity, low working potential, good stability, excellent electrical properties, enhanced selectivity and fast amperometric responses to glucose oxidation. Thus, as a nonenzymatic sensor, it is promising for future glucose determination development.
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