Perovskite-graphene nanocomposites of rare-earth LaFeO
3
-rGO and LaFeO
3
nanoparticles are synthesized and characterized. The preparation was done by citrate sol-gel method. The structural ...characterization has been performed using XRD and FT-IR. Scanning electron microscope (SEM) and atomic force microscope (AFM) were used to analyze the morphology of the prepared nanocomposite. Vibrating sample magnetometer (VSM) was used to study the magnetic properties of the investigated samples. Introducing graphene to the structure results increase in M
S
. Also, the optical and thermal properties have been measured and discussed, and the effect of graphene is observed where it decreases the band gap than reported for pure LaFeO
3
nanoparticles.
Rice straw nanofibers (RSNF) with high lignin content were used in making nanocomposites with graphene oxide (GO) at loading ratios from 0.625% to 5% (based on weight of RSNF). The prepared RSNF/GO ...films were characterized regarding their tensile strength, equilibrium moisture content (EMC), and electrical properties. Microstructure of the films was examined using scanning electron microscopy (SEM). Addition of 2.5% of GO resulted in increasing tensile strength and Young's modulus by 33.5% and 21.5%, respectively. Presence of GO significantly reduced moisture sorption of the films. Electrical conductivity measurement showed significant increase in permittivity (ε′) upon increasing GO loading. The ionic conductivity value of films containing 5% of GO was 10−7 S cm−1, which is acceptable value for use as antistatic and/or dissipated films. The electrical properties of the prepared low‐cost high‐lignin‐content RSNF/GO films could have potential use in flexible electronic applications such as in energy harvesting and storage.
Preparation of rice straw nanofibers/graphene oxide (RSNF/GO) nanocomposites films.
Herein, graphene nanocomposite of CuO–rGO is synthesized by simple precipitation reaction. Characterization by different techniques confirms the reduction of graphene oxide and formation of CuO–rGO. ...The CuO nanocrystals are uniformly distributed on graphene sheets. Neutron and X‐ray diffraction (XRD) prove the formation of single phase of CuO monoclinic crystal system with space group C2/c. Infrared spectroscopy shows vibration modes of graphene and CuO. Morphological characterization is carried out by scanning electron microscope (SEM) (SEM) and transmission electron microscope (TEM). It shows that the particle size ranges from 20 to 60 nm in which confirmed by four different theoretical approaches calculated from XRD peaks broadening data. The electronic properties using X‐ray photoelectron spectroscopy are also provided.
The reduction of graphene oxide and formation of CuO–rGO nanocomposite is achieved and confirmed; the crystallite size and micro strain are calculated and tested with four different theoretical approaches based on X‐ray diffraction peaks broadening. X‐ray photoemission spectroscopy and fast fourier transform infrared spectroscopy prove the reduction of graphene by disappearance of graphene oxide peak and prove the ability of using in energy storage applications.
Organic–inorganic hybrid perovskites (OIHs) are exceptionally promising sector of novel materials for optoelectronic applications. Herein, the OIHs of the formula (NH3)2(CH2)3CuCl4 labeled by C3CuCl ...and (NH3)2(CH2)4CuCl2Br2 labeled by C4CuClBr are prepared by slow evaporation method. The synthesis process is achieved by mixing equimolar ethanolic solutions ratios (1:1) of their basic components (organic/inorganic). Characterizations of these materials using microchemical analysis, energy dispersion X‐ray (EDX) and X‐ray diffraction (XRD) are discussed. The XRD is used to estimate the crystalline size for prepared compounds and found in the range of 38.8 and 48.8 nm for C3CuCl and C4CuClBr, respectively. The vibrational spectra are studied by Fourier transformation infrared spectroscopy (FTIR) and show the major diffraction peaks of compounds and their assignment. UV‐region strong absorption is clarified in the optical properties studied for Cu hybrid, whereas the bandgap energy estimated via Kubelka–Munk equation and found 2.8 and 3.85 eV for C3CuCl and C4CuClBr, respectively.
Cu hybrid perovskites diammonium series (NH3)2(CH2)3CuCl4 and (NH3)2(CH2)4CuCl2Br2 are successfully prepared and characterized to confirm the formation of the novel hybrid perovskites of average crystallite size 38.8 and 48.8 nm, respectively. These optical studies show strong absorption in UV region and energy gap of 2.85 eV ((NH3)2(CH2)3CuCl4) and 3.9 eV ((NH3)2(CH2)4CuCl2Br2).
In the present work, graphene oxide GO is prepared by chemical exfoliation of graphite using Hummer’s method. A facile and green synthesis of ZnO–rGO nanocomposite is performed using aloe vera plant ...extract. The characterization tools (XRD, FTIR, FESEM, HrTEM, AFM) proved the formation of single phase of ZnO–rGO nanocomposite. Since the environmental contamination caused by Cd(II) ion is a world issue, it has a harmful effect, especially on the human health and environment. Subsequently, our goal in this work is to find an accurate method for detection and adsorption of toxic Cd(II). ZnO and ZnO–rGO nanocomposites are prepared for removing Cd(II), and on behalf of increasing its removal efficiency, GO is added. The results showed a great improvement in removal efficiency reached up to 90% at pH 6 after 90 min.
Diammonium series of Cu hybrid perovskites of the formula (NH
3
)(CH
2
)
n
(NH
3
)CuCl
4
,
n
= 6–9 are prepared from an ethanolic solution in stoichiometric ratio 1:1 (organic/inorganic). Formation ...of the desired material was confirmed and characterizes by microchemical analysis, FTIR, XRD and XPS spectra. The structure consists of corner-shared octahedron CuCl
4
2−
anion alternative by organic (NH
3
)(CH
2
)
n
(NH
3
)
2+
cations. The organic and inorganic layers form infinite 2D sheet that are connected via NH···Cl hydrogen bond. The calculated lattice potential energy
U
pot
(kJ/mol) and lattice enthalpy Δ
H
L
(kJ/mol) are inversely proportional to the molecular volume
V
m
(nm
3
) and organic chain length. Optical properties show strong absorption peak at UV–visible range. The band gap energy calculated using Kubelka–Munk equation shows the decrease of the energy gap as organic chain length increases. The introduction of bromide ion to (NH
3
)(CH
2
)
n
(NH
3
)CuCl
2
Br
2
denoted 2C7CuCB hybrid has shifted the energy gap to lower values from 2.6 to 2.18 eV for 2C7CuCl (yellow) and 2C7CuCB (brown), respectively, at the same organic chain length. All elements of (NH
3
)(CH
2
)
9
(NH
3
)CuCl
4
and (NH
3
)(CH
2
)
7
(NH
3
)CuCl
2
Br
2
were found in XPS spectra, as well as valence band spectra.
In this work, facile synthesis of Mn
3
O
4
-reduced graphene oxide (Mn
3
O4-rGO nanocomposite is presented, in which the reduction of graphene oxide and the nucleation of Mn
3
O
4
on the graphene ...sheet occur simultaneously with the aid of hydrazine hydrate followed by heat treatment of the precipitate at 400°C in air. The characterization tools prove the formation of Mn
3
O
4
-rGO nanocomposite. The average crystallite size is 17 nm. When used as a supercapacitor electrode, the as-prepared Mn
3
O
4
-rGO exhibited excellent electrochemical performance with a specific capacitance of 411 F g
−1
at a current density of 1 A g
−1
, high rate capability of 54% retention at 10 A g
−1
, and good cycling stability (77% capacitance retention even after 3000 cycles). The electrochemical performance of Mn
3
O
4
-rGO nanocomposite is further explored by assembling a hybrid supercapacitor device using the Mn
3
O
4
-rGO nanocomposite as a positive electrode and an activated carbon as a negative electrode, the assembled-device exhibited the highest energy density of 28.35 Wh kg
−1
at a power density of 823 W kg
−1
, and still showed an energy density of 14.66 Wh kg
−1
at a power density of 6597 W kg
−1
. These findings make the Mn
3
O
4
-rGO nanocomposite a potential material for high-performing energy-storage systems.
Whereas ferric oxide particles are common catalyst for energetic oxidizers such as ammonium perchlorate (APC), reduced graphene oxide (RGO) with superior thermal conductivity as well as high ...interfacial surface area could be candidate substrate for advanced catalytic systems. This study reports on the facile synthesis of RGO-Fe
2
O
3
nanocomposite as a novel catalyzing agent for APC oxidizer. GO was developed via oxidation of graphite using Hummer’s method, while RGO was developed via GO reduction with hydrazine hydrate. RGO-Fe
2
O
3
nanocomposite was developed via direct precipitation method. Morphological characterization of RGO-Fe
2
O
3
nanocomposite demonstrated the formation of hematite RGO-Fe
2
O
3
nanocomposite in the form of rod-shaped crystals with average crystallite size 30 nm. The synthesized RGO-Fe
2
O
3
nanocomposite was effectively-encapsulated into APC particles via co-precipitation technique. The catalytic performance of RGO-Fe
2
O
3
nanocomposite on APC thermal behavior was evaluated using DSC and TGA. RGO-Fe
2
O
3
nanocomposite demonstrated superior catalytic performance; APC initial endothermic decomposition was decreased by 16% which could be ascribed to enhance the thermal conductivity and catalytic efficiency of the developed hybrid. APC total heat release was enhanced by 83%; this could be ascribed to superior interfacial surface area. Gaseous products could be efficiently-adsorbed on the catalyst surface offering high combustion enthalpy.
Hummer’s method was used to prepare graphene oxide (GO) by chemical exfoliation of graphite. Simple precipitation method was used for the preparation of hybrid nanocomposites MgO–rGO and Fe
2
O
3
...–rGO. A 0.3 Molar of corresponding metal nitrate solution and GO solution are used for the preparation process. XRD, FT-IR, and XPS were used to characterize the prepared nanocomposites. The reduction of GO into reduced rGO in the formed nanocomposites was confirmed. Morphological characterization showed the formation of needle-shaped nanocrystals of MgO successfully grown on graphene nanosheet with average crystallite size 8.4 nm. Hematite nanocomposite Fe
2
O
3
–rGO forms rod-shaped crystals with average crystallite size 27.5 nm. The saturation magnetization observed for Fe
2
O
3
–rGO is less than reported value for the pure Fe
2
O
3
nanoparticles. Thermal properties of as-prepared hybrid nanocomposites MgO–rGO and Fe
2
O
3
–rGO showed thermal stability of the prepared nanocomposite over long range of temperature.
Graphical Abstract
This study presents the fabrication of new, non-toxic perovskite solar cells using 2D cobalt-based perovskite materials. Three cobalt-based Organic–inorganic 2D hybrid perovskite (HOIP) materials ...were synthesized, and their photovoltaic properties were evaluated: NH
3
(CH
2
)nNH
3
CoCl
4
(n = 4, 9) and NH
3
(CH
2
)
7
NH
3
CoBr
2
Cl
2
. These materials encompassed varying organic chain lengths (short, medium, and long) as well as chloride and mixed chloride/bromide anions. The molecular structure was examined to establish correlations with the structural and optical properties. The synthesized compounds exhibited visible light absorption, with varying bandgap energy from 1.7 eV to 2.7 eV. To test the application of Co-based perovskites, two distinct solar cell architectures were employed. The first architecture, denoted as Architecture 1, consisted of the following layers: Glass/FTO/c-TiO
2
/m-TiO
2
/ZrO
2
/2D Co-based HOIP/C-electrode. The second architecture, referred to as Architecture 2, utilized a planar heterojunction structure deposited with different transport layers for electrons and holes. Specifically, it comprised the layers: Glass/ITO/SnO
2
/2D Co-based HOIP/Spiro-OMeTAD/Au. Among these architectures, Architecture 2 exhibited notable performance. It achieved a maximal open circuit voltage (Voc) of 0.93 V, and current density (Jsc) of 0.24 mA/cm
2
, with efficiency of 0.47%, and a fill factor (FF) of 78%. These findings demonstrate the effectiveness of adjusting the perovskite material composition and controlling the deposition conditions in raising solar cell efficiency.
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