scholarly journals Hydrothermal Synthesis of Nitrogen, Boron Co-Doped Graphene with Enhanced Electro-Catalytic Activity for Cymoxanil Detection

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6630
Author(s):  
Codruța Varodi ◽  
Florina Pogăcean ◽  
Maria Coros ◽  
Lidia Magerusan ◽  
Raluca-Ioana Stefan-van Staden ◽  
...  
Keyword(s):  
Standard Addition ◽  
Xrd Analysis ◽  
Current Increase ◽  
Peak Current ◽  
Co Doping ◽  
As Doping ◽  
Graphene Sample ◽  
First Case ◽  
Doped Graphene ◽  
Co Doped

A sample of nitrogen and boron co-doped graphene (NB-Gr) was obtained by the hydrothermal method using urea and boric acid as doping sources. According to XRD analysis, the NB-Gr sample was formed by five-layer graphene. In addition, the XPS analysis confirmed the nitrogen and boron co-doping of the graphene sample. After synthesis, the investigation of the electro-catalytic properties of the bare (GC) and graphene-modified electrode (NB-Gr/GC) towards cymoxanil detection (CYM) was performed. Significant differences between the two electrodes were noticed. In the first case (GC) the peak current modulus was small (1.12 × 10−5 A) and appeared in the region of negative potentials (−0.9 V). In contrast, when NB-Gr was present on top of the GC electrode it promoted the transfer of electrons, leading to a large peak current increase (1.65 × 10−5 A) and a positive shift of the peak potential (−0.75 V). The NB-Gr/GC electrode was also tested for its ability to detect cymoxanil from a commercial fungicide (CURZATE MANOX) by the standard addition method, giving a recovery of 99%.

Effect of Ce-Mn Codoping on the Structural, Morphological and Electrical Properties of the BaTiO3 Based Ceramics

2021 ◽  
Vol 11 (4) ◽  
pp. 12215-12226
Keyword(s):  
Dielectric Constant ◽  
Electrical Properties ◽  
Doping Concentration ◽  
Xrd Analysis ◽  
Solid State Reaction Method ◽  
Lattice Parameter ◽  
Stoichiometric Ratio ◽  
Co Doping ◽  
Mn Doped ◽  
Co Doped

Undoped, Cerium (Ce) doped, Manganese (Mn) doped and Ce-Mn co-doped Barium Titanate (BaTiO3) with the general formula Ba1-xCexMnyTi1-yO3 (where x = 0.00, 0.01, 0.02, 0.03, y = 0.00; x = 0.00, y =0.01, 0.02, 0.03; and x = y = 0.01, 0.02,0.03) were synthesized by solid-state reaction method and sintered at 1200 C for 4 hr with an aim to study their structural and electrical properties. The grain size of the samples has been estimated using the Scanning Electron Microscopy (SEM). The X-ray Diffraction (XRD) analysis indicates that the structure of the Ce-doped and Ce-Mn co-doped BaTiO3 is cubic. However, the undoped BaTiO3 and Mn-doped BaTiO3 confirmed the tetragonal-cubic mixed phases. With the change of doping concentrations, the positions of different peaks shifted slightly. The lattice parameter varied irregularly with increasing doping concentration because of Mn's changeable valency. EDX spectra confirmed the presence of Ba, Ti, Ce, and Mn contents in the co-doped samples with stoichiometric ratio. Crystallinity is observed to be clearly increased when Ce-Mn is co-doped in BaTiO3. J-V characteristic curves indicate transition from conducting to semiconducting nature for the doped and co-doped samples with the increase in temperature. The dielectric constant of the samples increases up to 4500 with the doping concentration. The higher values of dielectric constant are observed for the 2% Mn-doped and 1% Ce-Mn co-doped samples compared to the other undoped samples. For the undoped and Mn-doped samples, constant dielectric values increase with temperature but decrease for the Ce-doped and Ce-Mn co-doped samples. It is inferred that co-doping of BaTiO3 with Ce and Mn would be beneficial and economical for its applications.

Study of the Affecting Factors on the Desulfurization Activities of Co-Doped TiO2 Photocatalyst

2014 ◽  
Vol 700 ◽  
pp. 152-155
Author(s):  
Shu Qin Wang ◽  
Zhi Ping Han ◽  
Yin Tao Wang
Keyword(s):  
Removal Efficiency ◽  
Photocatalytic Oxidation ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Microwave Drying ◽  
Affecting Factors ◽  
Co Doping ◽  
Preparation Conditions ◽  
Utilization Time ◽  
Co Doped

The different preparation conditions of TiO2and NV co-doped TiO2prepared by the sol-gel method were evaluated through the SO2photocatalysis removal efficiency and continuous utilization time under the visible light. Results showed that the SO2removal reactions included adsorption and photocatalytic oxidation which was obvious for the NV co-doped TiO2; its continuous utilization time and removal efficiency reached 420min and 98.76% which was higher than that of TiO2,N- TiO2and V- TiO2when the co-doping of N and V, the calcining temperature was 500 °C by 3h and pH was 3.5 with the microwave by 23min.The XPS and XRD analysis indicated that coexisting V4+and V5+,microwave drying, calcination temperature and mixture of anatase and rutile strongly affected the desulfurization photocatalytic activity of NV co-doped TiO2.

Band-gap tuning of graphene by Be doping and Be, B co-doping: a DFT study

RSC Advances ◽  
2015 ◽  
Vol 5 (69) ◽  
pp. 55762-55773 ◽  
Author(s):  
Saif Ullah ◽  
Akhtar Hussain ◽  
WaqarAdil Syed ◽  
Muhammad Adnan Saqlain ◽  
Idrees Ahmad ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
First Principles ◽  
Density Functional ◽  
Functional Theory ◽  
Co Doping ◽  
Structural And Electronic Properties ◽  
Doped Graphene ◽  
Band Gap Tuning ◽  
Co Doped

First-principles density functional theory (DFT) calculations were carried out to investigate the structural and electronic properties of beryllium (Be) doped and, Be with boron (B) co-doped graphene systems.

Nitrogen and sulfur co-doped graphene counter electrodes with synergistically enhanced performance for dye-sensitized solar cells

2014 ◽  
Vol 2 (31) ◽  
pp. 12232-12239 ◽  
Author(s):  
Aravindaraj G. Kannan ◽  
Jinxing Zhao ◽  
Sung Geun Jo ◽  
Yong Soo Kang ◽  
Dong-Won Kim
Keyword(s):  
Solar Cells ◽  
Conversion Efficiency ◽  
Dye Sensitized Solar Cells ◽  
Counter Electrodes ◽  
High Conversion Efficiency ◽  
Co Doping ◽  
Dye Sensitized ◽  
Doped Graphene ◽  
Sensitized Solar Cells ◽  
Co Doped

Uniform co-doping of nitrogen and sulfur on graphene effectively catalyzes the triiodide reduction, resulting in high conversion efficiency of DSSCs.

Photoluminescence Study of In-Situ Rare Earth Doped PVT-Grown SiC Single Crystals

2005 ◽  
Vol 483-485 ◽  
pp. 445-448 ◽  
Author(s):  
Holger Schmitt ◽  
Ralf Müller ◽  
Manfred Maier ◽  
Albrecht Winnacker ◽  
Peter J. Wellmann
Keyword(s):  
Bulk Crystals ◽  
Photoluminescence Study ◽  
Co Doping ◽  
As Doping ◽  
Stabilizing Effect ◽  
Luminescence Yield ◽  
Secondary Ion ◽  
Rare Earth Doped ◽  
Co Doped

Several SiC bulk crystals were grown with erbium and ytterbium as doping materials. Erbium contents determined by secondary ion mass spectroscopy (SIMS) ranged from 1.2 · 1014 cm-3 to 1.04 · 1015 cm-3, while ytterbium contents were below SIMS detection limit. Photoluminescence (PL) investigations of the characteristic 4f-4f-transition lines revealed a reduced luminescence yield in highly nitrogen and aluminum co-doped samples. Also, samples without intentional co-doping grown on the C-face showed less luminescence intensity than those grown on the Si-face. A stabilizing effect of erbium doping on the 4H polytype was observed.

A DFT Study of CO and NO Adsorptions on AlN-, AlP-, and ZnO-doped Graphene Nanosheets

2016 ◽  
Vol 230 (2) ◽  
Author(s):  
Niwat Promthong ◽  
Nadtanet Nunthaboot ◽  
Wanno Banchob
Keyword(s):  
Density Functional ◽  
Gas Adsorption ◽  
Graphene Nanosheets ◽  
Nitrogen Monoxide ◽  
Density Functional Theory Calculations ◽  
Pristine Graphene ◽  
Functional Theory ◽  
Co Doping ◽  
Doped Graphene ◽  
Co Doped

AbstractDensity functional theory calculations were performed to investigate the adsorption abilities of carbon monoxide (CO) and nitrogen monoxide (NO) gas molecules onto pristine graphene nanosheet (GNS), and AlN-, AlP-, and ZnO-doped GNSs. The co-doping of AlN, AlP, and ZnO onto GNS can improve the CO and NO adsorption abilities of GNS. The gas adsorption abilities on the pristine and co-doped GNSs were determined to be, in decreasing order: ZnO-GNS ∼ AlP-GNS > AlN-GNS > pristine GNSs and AlP-GNS > AlN-GNS > ZnO-GNS > pristine GNSs for the adsorptions of CO and NO, respectively. These newly developed co-doped GNSs could be candidates for CO and NO gas storages. The adsorption geometries, adsorption energies, density of states, and charge transfers were also reported.

Sintering Mechanisms of Cobalt-Doped Ceria and Zirconia Electrolytes in Intermediate-Temperature Solid Oxide Fuel Cells

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Masashi Mori ◽  
Zhenwei Wang ◽  
Takanori Itoh
Keyword(s):  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Xrd Analysis ◽  
Liquid Phase Sintering ◽  
Solid Oxide ◽  
Intermediate Temperature ◽  
Cubic Phase ◽  
Oxide Fuel ◽  
Co Doping ◽  
Co Doped

Ce 0.9 Gd 0.1 O 1.95 (CGO) and (ZrO2)0.89(Sc2O3)0.1(CeO2)0.01 (ScSZ) have been proposed as possible alternative electrolytes in intermediate-temperature solid oxide fuel cells (SOFCs). In this study, the mechanisms of densely sintering Co-doped CGO and ScSZ electrolytes during the SOFC fabrication process were investigated using synchrotron X-ray diffraction (SR-XRD) analysis. The addition of CoO enhanced the sintering characteristics of both CGO and ScSZ. Based on the results of the SR-XRD analysis, it was found that CGO and CoO did not form a solid solution after heat treatment at 1200°C for 10 h. On the other hand, the solubility limit of Co in ScSZ was estimated to be ≤3 mol % after firing at 1400°C, and Co doping accelerated the conversion of the two phases of the fluorite structures with cubic and rhombohedral phases into a single cubic phase. Because no significant densification of the Co-doped ScSZ samples was observed before and after the phase change and Co diffusion, it suggests that these reaction sintering processes should not be strongly related to densification. From the results of scanning electron microscopy, Co doping suggests to assist the densification of the ScSZ samples through liquid phase sintering, similar to Co-doped CGO.

scholarly journals Nitrogen and Sulfur Co-Doped Graphene as Efficient Electrode Material for L-Cysteine Detection

Chemosensors ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 146
Author(s):  
Codruța Varodi ◽  
Florina Pogăcean ◽  
Alexandra Cioriță ◽  
Ovidiu Pană ◽  
Cristian Leoștean ◽  
...  
Keyword(s):  
Modified Electrodes ◽  
Aqueous Dispersion ◽  
Electrochemical Performances ◽  
Xps Analysis ◽  
Sample Analysis ◽  
Pharmaceutical Drug ◽  
Real Sample Analysis ◽  
As Doping ◽  
Doped Graphene ◽  
Co Doped

Two graphene samples co-doped with nitrogen and sulfur were synthesized by the hydrothermal method using thiourea as doping and reducing agent for graphene oxide (GO). An appropriate amount of thiourea was added to the aqueous dispersion of GO, previously sonicated for 30 min. The mixture was poured into an autoclave and placed in the oven for 3 h, at 120 and 200 °C. The samples were denoted NSGr-120 and NSGr-200, respectively, in agreement with the reaction temperatures. They were next morphologically and structurally characterized by advanced techniques, such as SEM/TEM, XPS, XRD, and FTIR. According to XPS analysis, the NSGr-120 sample has higher amounts of heteroatoms in comparison with NSGr-200, indicating that the reaction temperature is a crucial factor that affects the doping degree. In order to reveal the influence of the doping degree on the electrochemical performances of graphene-modified electrodes, they were tested in solutions containing L-cysteine molecules. The electrode with the best electrocatalytic performances, GC/NSGr-120, was tested to detect L-cysteine in a pharmaceutical drug, proving its applicability in real sample analysis.

Single–atom manganese and nitrogen co-doped graphene as low-cost catalysts for the efficient CO oxidation at room temperature

2021 ◽  
Vol 536 ◽  
pp. 147809
Author(s):  
Mingming Luo ◽  
Zhao Liang ◽  
Chao Liu ◽  
Xiaopeng Qi ◽  
Mingwei Chen ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Room Temperature ◽  
Low Cost ◽  
Single Atom ◽  
Doped Graphene ◽  
Co Doped

Promoting Hydrogen Evolution of g-C3N4 Based Photocatalyst by Indium and Phosphorus Co-doping

2021 ◽  
Author(s):  
Xiao-Hang Yang ◽  
Chi Cao ◽  
Zilong Guo ◽  
Xiaoyu Zhang ◽  
Yaxin Wang ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Post Treatment ◽  
Experimental Results ◽  
Indium Chloride ◽  
Co Doping ◽  
In Situ Copolymerization ◽  
Co Doped

Indium and phosphorus co-doped g-C3N4 photocatalyst (In,P-g-C3N4) was prepared by K2HPO4 post-treatment of indium doped g-C3N4 photocatalyst (In-g-C3N4) derived from in-situ copolymerization of dicyandiamide and indium chloride. The experimental results...

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