Doped Graphene Oxide Research Articles

Yttrium doped graphene oxide as a new adsorbent for H2O, CO, and ethylene molecules: Dispersion-corrected DFT calculations

A Grimme dispersion-corrected density functional theory (DFT-D) calculations are performed to explore the electronic structures and adsorption behaviors of graphene oxide (GO) and Yttrium doped graphene oxide (Y doped GO) toward the adsorption of H2O, CO, and C2H4 molecules. The HOMO and LUMO spatial distributions, the electrostatic potential charges, and the field that corresponds to the electrostatic potential are evaluated to understand the effect of the Yttrium doping on the electronic properties of the pristine graphene oxide. Calculated molecular and thermodynamic parameters indicate that the electronic structure of GO is obviously affected by the presence of yttrium atom. It can be seen that the adsorption energies of H2O, CO, and C2H4 molecules adsorption increase from 69.5, 17.4 and 34.7 kJ/mol over the pristine GO to 133.1, 182.4 and 214.2 kJ/mol for the Yttrium doped GO. We believe that the obtained results will provide beneficial insights for experimental research about the potential application of metal-doped graphene oxides as nanoscale adsorbents for water, carbon monoxide, and ethylene molecules.

Lightweight excellent microwave absorption properties based on sulfur doped graphene

Lightweight and high-efficiency electromagnetic wave (EMW) absorption sulfur doped graphene (S-GS) was fabricated by reducing and doping graphene oxide (GO) using chemical method. The obtained S-GS exhibits an extremely low reflection loss (RL), wide effective absorption frequency bandwidth at a thin coating thickness (d), light weight and low cost. The minimum RL reaches −52.3 dB at 17.5 GHz with a matching thickness of 1.22 mm. More excitedly, the EM absorption properties could be double-adjusted. By changing the amount of dopant and the thickness of S-GS, The minimum RL touches −52.2 dB at 9.4 GHz and −49.3 dB at 8.5 GHz, respectively, even much lower than most kinds of GS based composites which combined with polymers, magnetic nanoparticles and so on. In a word, S-GS can be promised to be an ideal candidate for constructing novel MW absorber with lightweight, strong absorption characteristics, and thin matching thickness.

Simultaneous Photoreduction and Nitrogen Doping of Graphene Oxide for Supercapacitors by Direct Laser Writing

Graphene-based supercapacitors have attracted tremendous attention owing to their outstanding electro-chemical performance. In terms of material, nitrogen(N)-doped graphene(NDG) displays enhanced specific capaci- tance and rate performance compared with bare graphene used as a supercapacitor electrode. However, it still remains a challenge to develop a facile and simple method of NDG in cost-effective manner. Here, we used a simple direct laser writing technique to accomplish the simultaneous photoreduction and N-doping of graphene oxide(GO) using urea as a N source. The N content of the resultant reduced N-doped graphene oxide(NGO) reached a maximum value of 6.37%. All reduced NGO(NRGO)-based supercapacitors exhibited a higher specific capacitance than those based on pure reduced GO(RGO). Interestingly, the electrochemical performance of NRGO-based supercapacitors varied with different contents of N species. Therefore, we can control the properties of the obtained NRGOs by adjusting the doping ratios, an important step in developing effective graphene-based energy storage devices.

Fabrication of anti-corrosion nitrogen doped graphene oxide coatings by electrophoretic deposition

This work assesses anti-corrosion properties of graphene and N-doped graphene coatings deposited on copper by an electrophoretic method. Graphene oxide (GO) precursor was synthesized by an improved Hummers' method, whereas N-doping was performed hydrothermally in the presence of ammonia. After nitrogenation, doped graphene oxide samples (NGO) contained a reduced amount of oxygen and about 9% w/w nitrogen as pyridinic, pyrrole, and graphitic groups. Nevertheless, it was possible to obtain a stable aqueous dispersion of NGOs, a prerequisite for the EPD process. According to SEM images, the EPD coatings were compact with minor defects. On the contrary, GO coating possessed cracks and large pores that resulted from gas evolution during electrolysis. Electrochemical studies showed that all coatings prevented copper from corrosion in saline solution, however, the nitrogenated coatings did not exhibit better anti-corrosion properties than reduced graphene oxide coating. A reasonable explanation of this finding is that some positive properties of the nitrogenated coatings, in terms of anti-corrosion action, like low hydrophilicity and good adhesion, were counteracted by their catalytic activity towards oxygen reduction reaction.

Polypyrrole doped graphene oxide reinforced epoxy nanocomposite with advanced properties for coatings of mild steel

In this paper epoxy coatings containing Polypyrrole–Graphene Oxide (PPy–GOs) hybrid nanocomposites with various weight fraction (0.5, 1 and 2 wt%) were prepared to investigate the effect of PPy-GO on the enhancement of anti-corrosion properties in epoxy based nanocomposite coatings on mild steel. PPy–GOs hybrids, PPy and GO were characterized by FT-IR, XRD, SEM and TEM analysis and their effect on the anticorrosion performance of the composite coatings, the epoxy (E), epoxy mixed with PPy-GO (EPGs), PPy (EP) and physically mixture of PPy and GO (EP + G) coatings were studied by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and Open Circuit Potential (OCP). The results demonstrated that the dispersion of PPy-GO hybrids in the epoxy coatings improved corrosion performance of coating compared to the other coatings and maximum corrosion resistance is achieved via adding 0.5 wt.% PPy-GO. This behavior related to the better dispersion and interaction between PPy-GOs hybrids and epoxy matrix compared to other fillers.

One-step synthesis of tunable nitrogen-doped graphene from graphene oxide and its high performance field emission properties

Simultaneous reduction, repairing and doping of graphene oxide has been realized by the chemical vapor deposition method, using acetonitrile as a nitrogen source. A step-wise increase of acetonitrile partial pressure from 15 to 90 Pa results in nitrogen doped graphene (NG) with gradually tuning N-doping concentration from 0.38 to 0.66 at% and systematically rising graphite-N ratio from 23.25 to 45.39%, which in turn modulates field emission performance and enhance the stability. Raman spectroscopy and X-ray photoelectron spectroscopy suggest pyrrolic-N and pyridinic-N doping bring defects, while defects decrease as N-doping concentration increases due to the rising of graphite-N ratio. Proper defects may increase emission site density and N-doping can reduce work function. When N-doping concentration is controlled at 0.42 at%, NG exhibits the considerable decreasing of turn-on field from 3.35 to 2.18 V/μm at the emission current of 10 μA/cm2 and increasing of field enhancement factor from 1835 to 2967. It also reveals a good field emission stability with no degradation, which is superior to pristine reduced GO emitters. It is suggested the NG with tuning concentration of three type nitrogen emitter is a widely candidate for various field emission devices and applications.

One-step hydrothermal synthesis of In2.77S4 nanoparticles doped graphene oxide hybrids as efficient counter electrodes in dye-sensitized solar cells

Dye-sensitized solar cells (DSSCs) have become a potential alternative to photovoltaic devices, which can convert solar energy into electrical energy. As an essential component of DSSCs, counter electrode (CE) materials play an important role in determining the performance of DSSCs. Thus, research should seek for a cost-effective and high-activity CE materials. In this work, we explored an efficient, low-cost (platinum (Pt)-free) CE made of hybrids of In2.77S4 nanoparticles and reduced graphene oxide (RGO) for DSSCs. In2.77S4-RGO hybrids were facilely synthesized via a one-step hydrothermal approach without template or complicated precursor. Especially during synthesis, glacial acetic acid was added to prevent the precipitation of In3+ ions. Thus, free In3+ and S2− ions can readily absorb onto the graphene oxide (GO) surface by electrostatic forces. Finally, In2.77S4 nanoparticle-doped GO hybrids were obtained under hydrothermal conditions. Based on electrochemical measurement in cyclic voltammetry, electrochemical impedance spectroscopy, and Tafel polarization curve tests, the as-prepared mesoporous In2.77S4-RGO hybrids exhibited remarkable electrocatalytic properties, charge–transfer capabilities, and electrochemical stabilities. As a result, the DSSCs assembled with In2.77S4-RGO hybrid CE exhibited a powder conversion efficiency of 6.72%, which is superior to that with Pt CE (6.30%). These findings suggest that In2.77S4-RGO hybrids can be used as a promising alternative CE in DSSCs.

A simple, eco-friendly and green approach to synthesis of blue photoluminescent potassium-doped graphene oxide from agriculture waste for bio-imaging applications.

2D carbon nanomaterials such as graphene and its oxide counterpart have sought good research attention for their application as well as fundamental interest. Especially the versatility of graphene oxide establishes its elite candidature in every field because of diverse application potential. Here we are reporting a greener, eco-friendly and cost effective one step hydrothermal route for the synthesis of potassium doped graphene oxide (K-doped GO) from agricultural waste i.e. Quercus ilex Fruit. The elemental analysis and XPS study showed the high percentage (6.81%) of natural doping of potassium. The K-doped GO is specific and demonstrates bright blue photoluminescence (PL) under UV-light (λex = 365 nm). Low toxicity, intracellular localization, good biocompatibility and strong PL properties of the synthesized K-doped GOs portray it as an excellent bio-imaging agent holding great promise in analytical and biological fields.

THE EFFECT OF GRAPHENE OXIDE ON THE STRUCTURAL AND ELECTRICAL PROPERTIES OF YTTRIUM FERRITE BASED NANOPOWDERS

In this study, Yttrium Ferrite based nano electroceramics were prepared by the doping at various ratios of graphene oxide by the hydrothermal method. The obtained doped and undoped samples were characterized by XRD, SEM, FTIR, DTA, UV-VIS-NIR spectroscopy, temperature dependent electrical resistance changes and dielectric measurements. From the XRD results, it is observed that the obtained samples are polycrystalline with an Orthorhombic structure. The crystal parameters are changed with the doping of graphene oxide. FTIR spectra indicate that the graphene oxide changes the peak intensities. This confirms the incorporation of the graphene oxide into the ceramic structure. The doping of the graphene oxide changes the optical band gaps of the samples. The dielectric constants of the samples are changed with the graphene oxide. The DC electrical conductivity measurements confirm the semiconducting behavior of the samples. The obtained results indicate that the electronic and nanostructure of the synthesized electroceramics can be controlled by the doping of graphene oxide for electronic and energy applications.

Optimization of heteroatom doped graphene oxide by deep eutectic solvents and the application for pipette-tip solid-phase extraction of flavonoids.

In order to improve the permeation and adsorption properties of graphene oxide, heteroatoms and deep eutectic solvent were introduced in this study. After being modified, the structural properties of graphene oxide were improved and the materials were applied to the determination of myricetin and rutin in tea sample by pipette-tip solid-phase extraction method. The materials were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-Ray diffractomer, energy dispersive spectroscopy, atomic force microscope, and specific surface area by Brunauer-Emmett-Teller N2 adsorption desorption analysis. Meanwhile, they were tested by static and dynamic adsorption. The result showed that the materials after modifying had better adsorption amount for myricetin and rutin than graphene oxide. The calibration graphs of myricetin and rutin in MeOH were linear over 0.10-500.00µg/mL, and the limits of detection and quantification were in the range of 0.00546-0.0182µg/mL and 0.00741-0.0247µg/mL, respectively. A reliable analytical method was developed for recognition targets in tea sample by DES modified nitrogen-doped graphene oxide with satisfactory extraction recoveries (myricetin 99.77%, rutin 98.14%). It was potential for the rapid purification of myricetin and rutin in tea sample combined with the pipette-tip solid-phase extraction.

Synergetic effect of metal-doped GO and TiO2 on enhancing visible-light-driven photocatalytic hydrogen production from water splitting

ABSTRACT Although titanium dioxide (TiO2) is frequently used as photocatalyst, but its wide band gap decreases its catalytic activity in the visible light. To improve the visible light activity, Cobalt (Co) and Nickel (Ni)-doped Graphene oxide (GO) supported TiO2 were fabricated. The characterization results showed that the successfully doping of the Co and/or Ni on the GO as well as the incorporation TiO2 in the nanocomposite catalyst. The photon-induced evolution of H2 was remarkably enhanced when Ni and Co doped GO was introduced. Furthermore, the optimum ratio of GO:Ni:TiO2 in the hybrids was 10:1:2, while the higher TiO2 ratio would decrease the hydrogen production performance and photocatalytic activity. In contrast, the catalytic activity and H2 production rate were increased by increasing the TiO2 ratio in the GO:Co:TiO2 nanocomposite catalyst and the highest performance was obtained at ratio of 10:1:5, respectively. The remarkably boosted photocatalytic performance under visible (solar) light may be mainly assigned to the synergetic effect of Ni/Co and GO supported TiO2.

Investigation of the Magnetic and Transport Properties of YBa2Cu3O7-δ High Temperature Superconductor Doped with Graphene Oxide

Magneto transport and magnetization are studied in graphene oxide (GO)-doped YBa2Cu3O7-δ (YBCO) high-temperature superconductor. The samples were prepared by sol-gel method with different weight percentage (0, 0.3, 0.5 wt.%) of GO. The transition temperature of GO-doped samples did not change in comparison with the pure YBCO. However, SEM images show that the GO doping reduces the grain average diameter, which results in an enhancement (up to a factor of ~ 2) of the critical current density and of the flux pinning force in the presence of different applied magnetic fields.

Simultaneous N doping and reduction of GO: Compositional, structural characterization and its effects in negative electrostatic charges repulsion

The present work is focused on the modification of reduced graphene oxide with nitrogen doping to achieve electrostatic charges repulsion as well as, the extensive characterization of generated material. Graphene related materials, such as graphene oxide (GO) and reduced graphene oxide (rGO) have a wide field of applications and can be easily modified to obtain specific characteristics such as the high repulsion capacity to negative electrostatic charges promoted by nitrogen doping and which may be useful in biomedical applications, for example, to repel negatively charged cholesterol particles, which are deposited in arterial walls and catalyze atherosclerosis disease. In this work we present detailed characterization graphene oxide (GO) and nitrogen doped reduced graphene oxide (N-rGO) obtained in a low temperature process. Stacked sheets of GO with wrinkles were found, by TEM a hexagonal atomic arrangement with a thickness of 2.2 nm was observed. A distortion of the network after doping was also found and was attributed to an increase in defects due to GO reduction and nitrogen presence. The interplanar spaces were corroborate by DRX being 3.51 Å for N-rGO and 8.37 Å for GO. The corresponding bonds for nitrogen doping were found by XPS and FTIR, the total content of N was 9.57% with predominance of pyrrolic nitrogen. By means of contact angle measurements, resultant angles for N-rGO samples were >100° with different biological materials negative charged, demonstrating the repulsion capacity of the N-rGO. From measurements by Electrostatic Force Microscopy (EFM) it was verified that the repulsive behavior is due to the electrical charge in the surface of N-rGO and the negative surface potential of the material was verified by Scanning Kelvin Probe Microscopy (SKPM). Finally, cell viability tests were carried out on endothelial cells, obtaining a favorable behavior in contact with N-rGO. The characterization results confirmed the reduction of graphene oxide doped with nitrogen and the increase of negative charge in the surface was attributed to the free electrons that have the pyrrolic nitrogen, which allows the repulsion of negative electric charges, making N-rGO an ideal candidate for different applications.

Recent advances in graphene-based nanomaterials: properties, toxicity and applications in chemistry, biology and medicine.

This review (with 239 refs.) summarizes the progress that has been made in applications of graphene-based nanomaterials (such as plaingraphene, graphene oxides, doped graphene oxides, graphene quantums dots) in biosensing, imaging, drug delivery and diagnosis. Following an introduction into the field, a first large section covers the toxicity of graphene and its derivatives (with subsections on bacterial toxicity and tissue toxicity). The use of graphene-based nanomaterials in sensors is reviewed next, with subsections on electrochemical, FET-based, fluorescent, chemiluminescent and colorimetric sensors and probes. The large field of imaging is treated next, with subchapters on optical, PET-based, and magnetic resonance based methods. A concluding section summarizes the current status, addresses current challenges, and gives an outlook on potential future trends. Graphical Abstract Schematic presentation of the potential applications of graphene-based materials in life science and biomedicine, emphatically reflected in some vital areas such as DNA analysis, biological monitoring, drug delivery, in vitro labelling, in vivo imaging, tumor target, etc.

In situ 3D bacterial cellulose/nitrogen-doped graphene oxide quantum dot-based membrane fluorescent probes for aggregation-induced detection of iron ions

The development of a bio-based fluorescent membrane sensor for iron ions is elaborated. A three-dimensional (3D) network structure of bacterial cellulose (BC) made by layer-by-layer in situ cultivation contained nitrogen doped graphene oxide quantum dots (N-GOQDs). The obtained BC/N-GOQDs were analyzed by SEM, TEM and XPS and demonstrated that the blue emissive N-GOQDs were homogeneously distributed in the BC mats through hydrogen bonding. These materials were found to be useful for the detection of iron ions in aqueous solutions. Experimental data showed the blue-emitting BC/N-GOQDs fluorescent probes exhibited a sensitive response to Fe3+ within a favorable concentration range of 0.5–650 μM with a very good lower limit detection of 69 nM at a signal-to-noise ratio of 3 (S/N = 3). Meanwhile, the BC/N-GOQDs–Fe3+ complexes has good reproducibility after treatment with EDTA. The quenching mechanism was attributed to strong coordination between surface functional groups (–NH2 and –OH) and Fe3+ which was successfully applied in real water samples. Diagram of quenching mechanism of the BC/N-GOQDs nanocomposites towards Fe3+ ions.

Heterogeneous catalytic degradation of organic pollutants by peroxymonosulfate activated with nitrogen doped graphene oxide loaded CuFe2O4

Nitrogen doped graphene oxide loaded CuFe2O4 nanoparticles (CuFe2O4-NG) catalyst was successfully synthesized by thermal annealing and hydrothermal reaction approaches for degrading organic pollutants by peroxymonosulfate (PMS) activation. CuFe2O4-NG exhibited superior degradation efficiency toward orange II among GO, NG, CuFe2O4 and CuFe2O4-NG. The obtained catalysts were systemically characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, Raman spectrum analysis and X-ray photoelectron spectroscopy to understand the relationship between inner structure and catalytic activity. It can recognize the key reactive oxygen species including SO4•–, •OH, O2•– and 1O2 in CuFe2O4-NG/PMS degradation system by electron paramagnetic resonance and free radical quenching studies, indicating the existence of both radical pathway and non-radical pathway. Based on the valence state changes of Cu and Fe in XPS spectra, the redox cycles between Fe(III) and Fe(II), Cu(II) and Cu(I) mediated by HSO5– contributed to the production of SO4•–, •OH and O2•–. Carbonyl groups and ketonic groups on the catalyst could promote the self-decomposition of PMS, leading to the generation of 1O2. The synergistic effect between NG and CuFe2O4 can accelerate the activation of PMS and pose the new insight for organic pollutants removal.

Exploration of the Binding Properties of the Azo Dye Pollutants with Nitrogen‐Doped Graphene Oxide by Computational Modeling for Wastewater Treatment Improvement

AbstractSystematic studies were carried out to investigate the binding properties of ten selected azo dye pollutants with nitrogen‐doped graphene oxide. Acid Blue 29, Acid Orange 5, Acid Orange 7, Acid Orange 8, Acid Orange 52, Blue 113, Direct Blue 71, hydrolyzed Reactive Black 5H, hydrolyzed Reactive Orange 16H, and hydrolyzed Reactive Orange 107H were selected to be studied. At the first step, docking studies were done to provide the best binding modes between azo dye and nitrogen–doped graphene oxide. In continue, molecular dynamics simulation method, molecular mechanics/generalized Born and surface area (MM/GBSA) analysis, and energy decomposition analysis were carried out to examine the strength and nature of interactions between azo dye pollutants and nitrogen–doped graphene oxide. Analyzing of interaction during molecular dynamics simulation showed that van der Waals interaction has the most important role on the binding of the azo dyes to the surface of the nitrogen‐doped graphene oxide. Also, the contribution of electrostatic and hydrogen bonding interactions are not ignorable. The –SO3H, –OH, and –NH2 moieties on the azo dyes have a contribution in hydrogen bonding with the epoxide and –OH functional groups and pyridinium–like and pyrrole–like nitrogen‐containing functional groups on the nitrogen‐doped graphene oxide. No contributions from the carboxylic acid moieties and graphite‐like nitrogen‐containing functional groups in the hydrogen bonding were observed. The binding energies related to ADs/NGO systems during the MD simulation process, calculated by MM/GBSA approach. Entry Azo dye Binding energy (kcal mol–1) 1 Acid Blue 29 –42.7 2 Acid Orange 5 –32.6 3 Acid Orange 7 –30.1 4 Acid Orange 8 –32.2 5 Acid Orange 52 –28.3 6 Blue 113 –55.2 7 Direct Blue 71 –67.3 8 Hydrolyzed Reactive Black 5H –30.2 9 Hydrolyzed Reactive Orange 16H –32.6 10 Hydrolyzed Reactive Orange 107H –27.0

Unusual pH - Dependent Electrochemical Activity of Nitrogen Doped Graphene Oxide Towards Selective and Simultaneous Determination of Hydroquinone and Catechol

Hydroquinone (HQ) and Catechol (CC) are the two important dihydroxybenzene isomers that have found widespread usage in dyes, pesticides, cosmetics and pharmaceuticals manufacturing industries as synthetic intermediates [1]. However, due to their toxicity and low degradability, they have been declared as important environmental pollutants to be monitored [2]. Therefore, it is imperative to develop a rapid and facile analytical method for the simultaneous determination of HQ and CC. In this regard, electroanalytical techniques have been preferred over conventional analytical techniques because of their cost–efficiency and high–speed analysis [3]. Unfortunately, due to the presence of same electroactive groups, the redox peaks of both these isomers overlap together, thereby resolution of them at conventional working electrodes has been rendered impossible without chemical or electrochemical modifications. In the past few years, the doping of atoms such as Nitrogen, Boron and Sulfur into graphene or graphene oxide lattices have evoked lot of interest [4]. These doped graphene oxides have large amount of edge sites, high surface area and electrical conductivity which in turn leads to superior electrochemical and catalytic activities [5]. In the present work, a simple, facile and one – pot hydrothermal strategy is presented for the synthesis of Nitrogen–doped graphene oxide (NGO) by employing Amitrole (AMT) as the nitrogen source. The successful N–doping into the graphene oxide lattices have been confirmed through FT–IR, FT–Raman and XPS techniques while, other characteristic properties were investigated using powder XRD, SEM, TEM and TGA. As an application, an electrochemical sensor based on the NGO–AMT modified glassy carbon electrode (NGO–AMT/GCE) has been developed for the sensitive and simultaneous determination of HQ and CC. Interestingly, the NGO–AMT/GCE exhibited a pH–dependent electrochemical activity towards the simultaneous sensing of these two dihydroxybenzene isomers in 0.1 M PBS. Moreover, the characteristic twin oxidation peaks of HQ and CC were observed at pH = 7.08 with a peak separation of about 110 mV using DPV technique. On the other hand, at pH = 5.08 and pH = 9.08 the corresponding oxidation peaks of CC and HQ were alone observed. This unusual behavior has been rationalized through the protonation of pyridinic nitrogen at lower pH and de-protonation of carboxylic acid active sites at higher pH (Fig.1). The proposed sensor was thus examined at pH 7.08 and found to have a linear range from 1 to 500 μM. The limits of detection (LOD, S/N = 3) were 15 and 20 nM, respectively for HQ and CC. Furthermore, the interference analysis has been carried out with some typical interfering agents and the performance of NGO–AMT/GCE was found to be satisfactory. As a practical application, the developed sensor was utilized for analyzing these isomers in tap water and exhibited reliable and stable recovery results.

A Novel Study: The Effect of Graphene Oxide on the Morphology, Crystal Structure, Optical and Electrical Properties of Lanthanum Ferrite Based Nano Electroceramics Synthesized by Hydrothermal Method.

Lanthanum Ferrite based nanocomposites were prepared with various Graphene oxide contents by the hydrothermal method. The crystalline structure, morphological properties, electrical and optical properties of samples were investigated. X-ray diffraction results indicate that all the nano electroceramics are polycrystalline with an Orthorhombic structure. Results from scanning and transmission electron microscopes indicate that the Bismuth ferrite/Graphene oxide powders have nanostructure. The optical band gaps of the nano electroceramics were calculated for the various amount of Graphene oxide. The electrical properties of samples were investigated with the temperature depend on conductivity measurements. The measurement shows that the electrical conductivity changes with increasing temperature and graphene oxide dopants of all samples. Activation energy (EA) values of the nanocomposites decrease with increasing graphene oxide content. The dielectric properties of Lanthanum Ferrite/Graphene Oxide nanocomposites (real and imaginer) with respect to frequency variation (1 KHz-5 MHz) were measured at room temperature. The relative permittivity (ɛ'), dielectric loss (ɛ″) and alternating current conductivity (σac) values of the samples were estimated. It is show that (ɛ'), (ɛ″) and (σac) increase with increasing frequency. The polarization-electric field hysteresis loop of all Lanthanum Ferrite/Graphene Oxide nano electroceramics was measured at the room temperature. The loop shows proper saturation with enhanced saturation polarization (Ps), remnant polarization (Pr) and coercive electric field (Ec). The obtained findings suggest that the physical and electrical properties of Lanthanum Ferrite/Graphene Oxide nano electroceramics can be changed by Graphene Oxide doping. These materials can be used for a variety of technological applications in the field of dielectric and ferroelectric.

Synergistic enhancement of the visible-light photocatalytic activity of hierarchical 3D BiOClxBr1-x/graphene oxide heterojunctions for formaldehyde degradation at room temperature

A novel 3D bismuth 3D-BiOClxBr1-x/GO heterojunction with excellent visible light activity was synthesized by doping graphene oxide (GO) in as-prepared 3D-BiOCl0.5Br0.5 via a facile hydrothermal method. The synthesized 3D-BiOCl0.5Br0.5/GO heterojunction exhibited a hierarchical globose corolla-like nanoscale structure with a large surface area and a suitable pore size. GO doping was favorable for forming a chemical bond between GO and bismuth oxyhalide. Introducing a small amount of GO sheets into 3D-BiOCl0.5Br0.5 can improve the surface chemical structure of 3D-BiOCl0.5Br0.5, increase surface adsorption sites, accelerate electron transmission and avoid e− and h+ recombination. In this way, the adsorption and degradation capacities of 3D-BiOCl0.5Br0.5/GO to formaldehyde were significantly enhanced. Under visible light irradiation, the synthesized samples demonstrated advanced photocatalytic capacities for formaldehyde degradation when compared with pure 3D-BiOCl0.5Br0.5, indicating synergistic enhancement effects between GO and 3D BiOCl0.5Br0.5. The efficiency of the 3D-BiOCl0.5Br0.5/GO heterojunction for formaldehyde degradation was over 89.6% within 120 min at room temperature, which shows promise for effectively treating environmental pollution caused by indoor aldehyde emissions. Enhanced photocatalytic activity mechanisms of the 3D-BiOCl0.5Br0.5/GO heterojunction were proposed based on experimental findings.