We present a simple, environment-friendly, and fast synthesis of nitrogen-doped graphene quantum dots (N-GQDs) on copper foil by chemical vapor deposition using exclusively chitosan, a cheap and ...nontoxic biopolymer, as a carbon and nitrogen precursor. We characterized the synthesized N-doped graphene quantum dots using Raman spectroscopy, XPS, AFM, HRTEM, and HRSEM and found them to be in the range 10–15 nm in diameter and 2–5 nm-thick with 4.2% of maximum nitrogen content. The proposed growth mechanism process includes three key steps: (1) decomposition of chitosan into nitrogen-containing compounds, (2) adsorption of reactive species (HCN) on the copper surface, and (3) nucleation to form N-doped graphene quantum dots. The synthesized N-GQDs exhibit photoluminescence (PL) emission in the visible band region, thus making them suitable for applications in nano-optoelectronics.
This study targets the investigation of three pyrimidine-bichalcophene derivatives (MA-1230, MA-1231, MA-1232) for the prevention of corrosion on copper in 1 M HNO
3
via
weight loss (WL), ...potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) techniques. The surface morphology was also analyzed by different methods. It was found that the inhibition efficiency (%
η
) increased by increasing the doses of pyrimidine derivatives and the temperature of the medium. Weight loss data revealed the better adsorption of MA-1232 on the Cu surface at increased inhibitor dose, reaching a maximum efficiency of 99.14% at a dose of 21 μM at 45 °C. The best description of the adsorption of the investigated derivatives on the copper surface was given by the Langmuir isotherm. Some important thermodynamic parameters for the studied inhibitors were computed and are discussed herein. The polarization studies showed that the pyrimidine-bichalcophenes act as mixed inhibitors. Computational chemical approaches were used with informative yields, including quantum-chemical and molecular dynamics simulation techniques, which agree with the experimental results. The results obtained from all tested methods are strongly accepted.
This study targets the investigation of three pyrimidine derivatives (MA-1230, MA-1231, MA-1232) for the prevention of corrosion on copper in 1 M HNO
3
via
weight loss (WL), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) techniques.
The present work aims to study 6-amino-4-aryl-2-oxo-1-phenyl-1,2-dihydropyridine-3,5-dicarbonitrile derivatives namely: 6-Amino-2-oxo-1,4-diphenyl-1,2-dihydropyridine-3,5-dicarbonitrile (PdC-H), ...6-Amino-2-oxo-1-phenyl-4-(p-tolyl)-1,2-dihydropyridine-3,5-dicarbonitrile (PdC-Me) and 6-Amino-4-(4-hydroxyphenyl)-2-oxo-1-phenyl-1,2-dihydropyridine-3,5-dicarbonitrile (PdC-OH) as corrosion inhibitors to provide protection for carbon steel in a molar hydrochloric acid medium. Chemical measurements such as (weight loss) and electrochemical techniques such as (Potentiodynamic polarization, electrochemical impedance spectroscopy, and Electron frequency modulation) were applied to characterize the inhibitory properties of the synthesized derivatives. The adsorption of these derivatives on the carbon steel surface was confirmed by Attenuated Total Refraction Infrared (ATR-IR), Atomic Force Microscope (AFM), and X-ray Photoelectron Spectroscopy (XPS). Our findings revealed that the tested derivatives have corrosion inhibition power, which increased significantly from 75.7 to 91.67% on the addition of KI (PdC-OH:KI = 1:1) to inhibited test solution with PdC-OH derivative at 25 °C. The adsorption process on the metal surface follows the Langmuir adsorption model. XPS analysis showed that the inhibitor layer consists of an iron oxide/hydroxide mixture in which the inhibitor molecules are incorporated. Computational chemical theories such as DFT calculations and Mont Carlo simulation have been performed to correlate the molecular properties of the investigated inhibitors with experimental efficiency. The theoretical speculation by Dmol3 corroborates with the results from the experimental findings.
Electrochemical water splitting, which generates both hydrogen and oxygen, using highly efficient and low‐cost noble metal‐free (Pt, Ru, Ir etc.) electrocatalyst is an economical and green approach ...for the alternative energy source. Due to their conductivity, durability and long‐term stability, carbonaceous containing hybrid materials are used as promising electrodes for total water splitting. Herein, the design of metal‐phosphide (Cu3P) with graphitic carbon‐nitride (g‐C3N4) nanocomposite on 3D‐graphene is reported, a new model electrocatalyst that in turn, render superior electrocatalytic performance with long‐term stability. The excellent electrocatalytic performance is analyzed in terms of overpotentials of 67 mV and 255 mV at a current density of 10 mA/cm2 with a small Tafel slope of 45 and 40 mV/dec for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. The overall water splitting performance has been tested in 1 M KOH electrolyte, and the catalyst exhibits a very low cell voltage of 1.54 V to achieve a current density of 10 mA/cm2 with impressive stability of at least 35 hours with no loss of potential. This work sheds new insight into the design and synthesis of highly stable electrocatalyst that could be an apt choice for an attractive paradigm for commercial water electrolysis in renewable electrochemical energy conversion.
Water splitting: Graphitic carbon nitride (g‐C3N4) and Copper phosphide (Cu3P) are decorated on highly pours 3D‐Graphene matrix. This nano composite(3D‐Graphene‐g‐C3N4/Cu3P) work as an efficient bifunctional electrocatalyst for overall water splitting.
Edible films based on chitosan biguanidine hydrochloride and CMC were optimized for the minimum water vapor permeability (WVP) using the 3-level factorial design. Titanium oxide nanoparticles (nTiO2) ...were incorporated in different contents into the optimized film (Owvp). FTIR and 1H NMR confirmed the successful preparation of films. FE-SEM showed that nTiO2 was homogeneously distributed, with a size of about 25.78 nm for the film containing 5 wt% of nTiO2. XRD was used to study the film's crystallinity, and calculate the crystallite size of nTiO2 using Debye–Scherrer Equation. Thermal stability, by TGA, was improved while the water vapor permeability was reduced upon increasing the nTiO2 content. Color measurements showed that the nTiO2 incorporation didn't significantly affect the transparency. Elongation at break was decreased upon nTiO2 incorporation while tensile strength and Young's modulus were increased with increasing nTiO2 up to 3 wt% then begin to decrease. The nanocomposites exhibited significant UV-barrier properties and enhanced antimicrobial activity especially at high contents of nTiO2. Shelf-life studies on green bell pepper coated with the nanocomposite films showed excellent resistance to mass loss and spoilage during storage. The obtained data confirm the efficiency of the prepared nTiO2 nanocomposite films to extend the shelf-life of food.
•Carboxymethyl cellulose and chitosan biguanidine was optimized to a minimum WVP.•nTiO2 was added to the optimized system in different contents.•nTiO2 improved WVP, thermal, mechanical, UV-shielding and antimicrobial properties.•nTiO2 didn't affect the film's transparency.•nTiO2 nanocomposite extended the shelf-life of pepper.
Chitosan biguanidine hydrochloride (CBg) was prepared as a novel multifunctional biodegradable polymer with antimicrobial and excellent water-solubility properties, and used as a crosslinker to ...prepare carboxymethyl cellulose (CMC)/alginate (A)/CBg edible coating. FTIR confirmed the successful preparation of CBg and CMC/A/CBg films. Wide-angle X-ray diffraction showed that the amorphous structure of CMC/A had some degree of order after CBg addition. The film thickness and solubility were decreased after CBg addition due to the formation of a dense crosslinked structure. CBg addition significantly improved the thermal properties of the films as detected from the calculated IPDT values from TGA curves. Water vapor permeability was reduced to 54% of the value of CMC/A when CBg was added by15 wt%. The addition of CBg didn't change the transparency of CMC/A films. The mechanical properties and antibacterial properties were significantly enhanced after the addition of CBg. CMC/A/CBg were coated on tomato fruits, and the shelf-life studies showed that the storage weight loss was significantly reduced, and the spoilage was inhibited after coating. These results suggest that CMC/A/CBg edible coating might be a promising candidate in food preservation industries.
•Chitosan biguanidine hydrochloride (CBg) was used as a crosslinker for carboxymethyl cellulose (CMC)/alginate (A) system.•Films exhibited a reduced water vapor permeability and good color properties with CBg addition.•Films mechanical, thermal and antibacterial properties were improved with increasing the CBg percent.•Tomato spoilage was inhibited during the storage period when coated with CMC/A/CBg films.•The mass loss of tomatoes was significantly reduced for coated tomatoes.
In this work, three different types of surfactants, namely, dodecyl trimethyl ammonium chloride (DTAC, C
12
H
25
N (CH
3
)
3
Cl)
−
, octyl phenol poly(ethylene glycol ether)
x
(TX-100, C
34
H
62
O
11
...for
x
= 10) and dioctyl sodium sulfosuccinate (AOT-100, C
20
H
37
O
7
NaS) with corrosion restraint were utilized as corrosion inhibitors for 1037 CS in 0.5 M HCl. The protection efficacy (% IE) was indicated by weight loss and electrochemical measurements. Polarization curves showed that the investigated compounds are mixed-type inhibitors. The protection efficacy (% IE) increases with the increase in the surfactant concentration and reached 64.42-86.46% at 8 × 10
−4
M and 30 °C. Adsorption of these utilized surfactants (DTAC, TX-100, and AOT) onto the CS surface concurred with the Langmuir adsorption isotherm. Impedance data revealed that by increasing the surfactant concentration, the charge transfer resistance (
R
ct
) increases and
vice versa
for the capacitance of double layer (
C
dl
). Surface morphological investigations such as scanning electron microscopy (SEM) combined with EDX and atomic force microscopy (AFM) were used to further investigate the inhibitors' protective abilities. Monte Carlo simulations showed the great interaction between the tested surfactants and the metal surface of the CS. The theoretical results (density functional theory, DFT) were in good agreement with experimental measurements. The restraint efficiencies of anionic, neutral, and cationic surfactants regarded a certain dating to HSAB precept and Fukui indices.
In this work, three different types of surfactants DTAC, C
12
H
25
N (CH
3
)
3
Cl
−
, TX-100, C
34
H
62
O
11
for
x
= 10) and AOT-100, C
20
H
37
O
7
NaS) with corrosion restraint were utilized as corrosion inhibitors for 1037 CS in 0.5 M HCl.
This review provides recent developments in the current status and latest synthetic methodologies of biphenyl derivatives. Furthermore, this review investigates detailed discussions of several ...metalated chemical reactions related to biphenyl scaffolds such as Wurtz-Fittig, Ullmann, Bennett-Turner, Negishi, Kumada, Stille, Suzuki-Miyaura, Friedel-Crafts, cyanation, amination, and various electrophilic substitution reactions supported by their mechanistic pathways. Furthermore, the preconditions required for the existence of axial chirality in biaryl compounds are discussed. Furthermore, atropisomerism as a type of axial chirality in biphenyl molecules is discussed. Additionally, this review covers a wide range of biological and medicinal applications of the synthesized compounds involving patented approaches in the last decade corresponding to investigating the crucial role of the biphenyl structures in APIs.
This review provides recent developments in the current status and latest synthetic methodologies of biphenyl derivatives.
The applications of edible coatings stemmed exclusively from alginate in food packaging are restricted due to their inherent deficient antimicrobial, barrier, and UV-barrier properties. In this work, ...we aimed to design smart alginate-based coatings for active food packaging through the addition of both aloe vera (AV) and garlic oil (GO). The interactions between the film components were verified by FTIR and XRD. Thermal and mechanical properties were improved by the presence of AV and GO. The presence of AV and GO did not significantly influence the transparency of alginate films. The films exhibited a significant UV-shielding to all UV regions. Water vapor permeability was significantly (p < 0.05) reduced either through the incorporation of AV or GO. The antimicrobial properties of the prepared films were considerably improved by the presence of AV and GO. The shelf-life of tomatoes (Solanum lycopersicum L.) was extended when coated with the alginate film incorporated with AV and GO. Owing to the outstanding UV-shielding, mechanical, thermal, and antimicrobial properties, the alginate/AV/GO active coatings could potentially be implemented in the food packaging industry.
•Aloe vera (AV) and garlic oil (GO) were incorporated into alginate.•UV-shielding properties were significantly improved compared with neat alginate.•GO and AV significantly improved thermal, mechanical and antimicrobial properties.•The prepared active edible films extended the shelf-life of tomatoes.•The prepared active edible films could be used potentially in food packaging.
In the present work, the Curam drug was used as an eco‐friendly corrosion inhibitor for the protection of stainless steel 304 (SS‐304) in 2.0 M HCl solution. The inhibition efficiency was determined ...by mass loss (ML), Potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) measurements. The surface morphology analysis carried out using Fourier transform infrared spectroscopy (FT‐IR) and atomic force microscopy (AFM). ML data prove that with an increase in the temperature, Curam still exhibits good anti‐corrosion performance. The inhibition efficiency of Curam can still be maintained at about 72% at 318 K. The data of electrochemical measurements indicate that Curam is the mixed‐type inhibitor. The adsorption process of Curam on the SS‐304 surface obeys the Langmuir adsorption isotherm. FT‐IR and AFM analysis showed the excellent inhibition performance of Curam for SS‐304 dissolution in an acidic medium. The data obtained by chemical and electrochemical measurements are in good agreement with one another.
Curam drug used as an eco‐friendly corrosion inhibitor for protection of SS‐304 in acidic solution. Inhibition efficiency was determined by chemical and electrochemical methods. Curam drug acts as a good corrosion inhibitor for SS‐304 protection. The results showed that Curam drug acts as a mixed type inhibitor. AFM and FT‐IR analysis pointed that a protective adsorbed layer of inhibitor is formed on the metal surface. The results obtained from ML, PDP, and EIS methods were in good agreement.
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