Sulfur-doped Graphene Research Articles

Production of Sulphur-Doped Graphene Oxide as an Anode Material for Na-Ion Batteries

Sodium-ion batteries have been the focus of interest in recent years due to abundance and cost-effectiveness of sodium resources globally as opposed to lithium. In this work, sulfur-doped graphene oxide (SGO) was synthesized using a straightforward, one-step, cost-effective, and eco-friendly chronoamperometric method at room temperature. The resulting powder was then utilized as active anode material for Na-ion batteries. The surface of the synthesized SGO powder, which consists of approximately three layers with 19 sp2 hybridized carbon rings and a domain size of about 50 nm, is covalently doped with –C-SOx-C- (x = 2,3) groups. The deduced diffusion coefficient from electrochemical impedance spectroscopy and galvanostatic intermittent titration technique measurements for SGO as anode in NIBs is in the range of 10−11–10−12 cm2.s−1. At 0.1 C rate, the initial discharge capacity recorded 256.7 mAh.g−1 at 0.1 C rate. In addition, the capacity retention for long-term cycling of 100 cycles at 2 C rate was 99.85%. The unique structure of SGO allows us to achieve satisfactory anode performance in capacity and rate capability, with potential for further enhancement.

Corrosion protective and antibacterial epoxy coating via benzyldisulfide‑sulfur-doped graphene oxide with machine-learning simulation support

This paper presents a novel approach to enhancing corrosion resistance and antibacterial properties of polymer coatings. Using benzyldisulfide (BDS) as a precursor, sulfur-doped graphene oxide (BGO) nanoflakes were fabricated through a hydrothermal method. The sulfur atoms were successfully integrated into the GO structure and its reduction through high-temperature treatment was validated by a number of experiments, including FE-SEM/EDS, FTIR, Raman, and XPS studies. The GO and BGO nanoflakes were then embedded in an epoxy‑silicone matrix. The prepared BGO-incorporated coating exhibited remarkable hydrophobicity and superior performance in electrochemical impedance spectroscopy (EIS) than the GO-containing counterparts. According to the study, the exceptional corrosion protection observed in BGO-incorporated coating can be attributed to the hydrophobic nature and corrosion inhibition properties of the sulfur provided by the S-doped nanosheets. Furthermore, a neural network was applied to EIS data. Results showed that long-term EIS curves could be acceptably predicted using short-term EIS data. Moreover, the presence of BGO nanoparticles increased the generation of reactive oxygen species and significantly improved the coating's antibacterial activity. Overall, this study highlights the potential of BGO in improving coating antibacterial activity and corrosion protection.

Unveiling the potential of graphene and S-doped graphene nanostructures for toxic gas sensing and solar sensitizer cell devices: insights from DFT calculations.

In this work, we explore the potential of 2D materials, particularly graphene and its derivatives, for eco-friendly electricity generation and air pollution reduction. Leveraging the significant surface area of graphene nanomaterials, the susceptibility of these graphene-based nanostructures to hazardous substances and their applicability in clean solar cell (SSC) devices were systematically investigated using density functional theory (DFT), as implemented within Gaussian 5.0 code. Time-dependent DFT (TD-DFT) was employed to characterize the UV-visible spectrum of unstrained nanostructures. Herein, we considered three potentially harmful gases-CO, NH3, and Br2. Adsorption calculations revealed a notable interaction between the pure graphene nanostructure and Br2 gas, while the S-doped counterpart exhibited reduced interaction. Saturated S-doped nanostructures demonstrated an enhanced affinity for NH3 and CO gases compared to their pure S-doped counterparts, attributed to the sulfur (S) atom facilitating gas molecule binding to the nanostructure's surface. Furthermore, simulations of the SSC device architecture indicated the superior performance of the pure graphene nanostructure in terms of light-harvesting efficiency, injection energy, and electron injection into the lower conduction band of CBM titanium dioxide (TiO2). These findings suggest a potential avenue for developing nanostructures tailored for SSC devices and gas sensors, offering a dual solution to address air pollution concerns. Density function theory was used to compute the ground and excited state properties for pure and sulfur-doped graphene nanostructures. The hybrid function B3LYP with a 6-31G* basis set was utilized to describe the exchange correlation. Gauss Sum 2.2 software is used to estimate the density of state (DOS) for all structures under investigation.

The development of sensitive graphene-based surface acoustic wave sensors for NO2 detection at room temperature

Bilayer graphene (Bl-Gr) and sulphur-doped graphene (S-Gr) have been integrated with LiTaO3 surface acustic wave (SAW) sensors to enhance the performance of NO2 detection at room temperature. The sensitivity of the Bl-Gr SAW sensors toward NO2, measured at room temperature, was 0.29º/ppm, with a limit of detection of 0.068 ppm. The S-Gr SAW sensors showed 0.19º/ppm sensitivity and a limit of detection of 0.140 ppm. The origin of these high sensitivities was attributed to the mass loading and elastic effects of the graphene-based sensing materials, with surface changes caused by the absorption of the NO2 molecules on the sensing films. Although there are no significant differences regarding the sensitivity and detection limit of the two types of sensors, the measurements in the presence of interferent gases and various humidity conditions outlined much better selectivity and sensing performances towards NO2 gas for the Bl-Gr SAW sensors.Graphical

Integrated nanozyme electrochemical sensor for the detection of tannic acid: An advanced approach to rapid and efficient environmental monitoring

This study presents a novel methodology for the rapid on-site detection of tannic acid (TA), a prevalent organic contaminant in various natural environments, notably in plant-derived sources. The proposed approach involves the development of a compact integrated electrochemical sensor incorporating a nanozyme system. Specifically, this system comprises Fe2O3 nanoparticles (NPs) embedded within a chitosan (CS) matrix, immobilized onto a sulfur-doped graphene (S-Gr) substrate deposited on a gold electrode (AuE). The Fe2O3NPs exhibit peroxidase-like artificial enzyme activity, contributing to exceptional stability and catalytic efficiency in TA oxidation processes. Additionally, the CS matrix acts as a stabilizing agent, enhancing the performance and recyclability of the nanozyme. Furthermore, the S-Gr nanomaterial facilitates rapid electron transfer, leading to heightened sensitivity and prompt response times. The integration of these advanced nanomaterials with a microfabricated electrode presents an economically feasible, reliable, and effective solution for TA detection, with promising prospects for large-scale deployment and environmental monitoring. The Fe2O3CS-S-Gr/AuE sensing system demonstrates a calculated limit of detection (LOD) of 3.6 × 10−3 µM and an increased sensitivity of 0.2 µA×µM−1, with a wide linear concentration range spanning from 0.01 to 1000 µM for TA detection. Notably, the recovery values obtained for surface water samples fall within the range of 97.7 % to 99.5 %, indicating strong agreement with results derived from the standard method, UHPLC-MS/MS.

One-step sustainable preparation of laser induced S-doped graphene for assembly of high-performance supercapacitors

Lignin, an industrial by-product that is abundant, renewable and has aromatic ring characteristics, is regarded as an ideal raw material for the synthesis of two-dimensional graphene materials. However, the sustainable development of graphene produced from lignin faces thorny challenges such as environmental pollution, low yield, cumbersome steps and harsh conditions. In this study, low-energy, green, large-scale one-step preparation of sulfur-doped graphene was achieved by co-blending lignin and sodium alginate into a fully biomass-based film, followed by easy-to-operate laser etching. Among them, alkaline lignin not only served as a carbon source but also acted as a sulfur doping source, avoiding the use of additional sulfur doping reagents. The results showed that the sheet resistance of graphene gradually decreased with the increase of laser power. The sheet resistance of graphene prepared when the laser power was 90% was as low as 8 Ω sq−1, which provided an inherent advantage for the subsequent assembly of flexible micro-supercapacitors. The specific capacitance and high energy density of the resulting supercapacitor were as high as 88.29 mF cm−2 and 12.26 μW h cm−2, respectively. This method successfully developed a sustainable and low-energy graphene preparation method, paving the way for the sustainable development of flexible energy storage devices.

Covalent Attachment of Sulfur-doped Graphene Quantum Dots to Glucose Oxidase via Diimide-activated Amidation

The conjugation of biomolecules to quantum dots has recently gained attention in the field of bionanotechnology. Graphene quantum dots (GQDs) have been employed in various sensing applications due to their tunable fluorescence, controllable size, low cytotoxicity, and high biocompatibility. In this work, sulfur-doped graphene quantum dots (S-GQDs) were conjugated to glucose oxidase (GOx) for the potential detection of glucose. Fluorescent S-GQDs were synthesized via one-step pyrolysis of citric acid and thioglycolic acid at 200 °C. S-GQDs were conjugated to GOx using the carbodiimide/succinimide (EDC/NHS) coupling reaction, followed by purification via centrifugal ultrafiltration. Fluorescence spectroscopy, UV-Vis absorption spectroscopy, and transmission electron microscopy were employed to characterize the S-GQDs and S-GQD-GOx conjugates. The S-GQDs obtained had an average diameter of 49.8 ± 7.4 nm (n = 12) and emitted strong blue fluorescence (λem = 460 nm) when excited with 365-nm UV light. Trinder’s assay was used to assess the catalytic activity of free GOx and the S-GQD-GOx conjugates. The S-GQD-GOx conjugates consistently showed significantly greater catalytic activity compared to free GOx. The results obtained open avenues for the fabrication of a sensitive fluorescent GQD-based glucose probe in the future.

Design and construction of pilot sludge drying package for the excess sludge in petrochemical industries: Heavy metals determination in sludge by polarography and atomic absorption spectrometry

In this research, according to the high amount of sludge in a petrochemical company, an iron package type of drying sludge bed was made/designed with carbon steel. Then, the drying sludge pond was filled with layers of sand with different mesh sizes. The excess sludge from the sedimentation pond was passed over this bed, and the amount of sludge removed by the bed was obtained at %96. The values of heavy metal and microbial forms were determined using the proposed method based on activated sludge after wastewater treatment. For the validation process, 10 mL of deionized water (DW) was mixed with 1.0 g of dried sludge with pure nitric acid (2% HNO3), and then the solid phase was filtered with the Whatman filter (WF). The concentration of heavy metals (As, Cd, Cu, Pb, Hg, Mo, Ni, Co, Se, Zn) in the remaining solution of sludge (mg kg-1) and wastewater (µg L-1) was extracted/ separated based on sulfur-doped graphene oxide adsorbent (SDGO) by solid-phase microextraction procedure (SPME) before being determined by the flame and hydride generation atomic absorption spectrometry (F-AAS; HG-AAS) which had similar range to the polarography analysis. The LOD, linear range and preconcentration factor (PF) for metals were obtained.

High Energy Density Primary Lithium Battery with Fluorinated S-Doped Graphene

Sulphur-doped graphene was fluorinated using molecular fluorine (F2). First, the fluorination conditions were adapted in order to be mild enough to maintain S in the carbon lattice and form S-F bonds. An unusually weakened C-F bonding for an F/C ratio of 0.71 was then achieved, which allowed enhanced performances when used as a cathode in primary lithium batteries. The material prepared at a moderate fluorination temperature of 70 °C for a period of 60 min exhibits a high mid-discharge reduction potential of 3.11 V at 10 mA/g and a power density of 3605 W/kg at a discharge rate of 2C. These electrochemical properties make the fluorine/sulfur co-doped graphene a promising material.

Single Vanadium Atom Achored on Sulfur-Doped Graphene as an Efficient Electrocatalyst toward the Nitrogen Reduction Reaction: A Computational View

Single Vanadium Atom Achored on Sulfur-Doped Graphene as an Efficient Electrocatalyst toward the Nitrogen Reduction Reaction: A Computational View

GOQDs and GOQDs-NS-doped Carbocatalysts: A Concise Study on Production and Use in One-pot Green MCRs.

Nowadays, the catalysts' usage in chemical reactions is unavoidable, and this has led scientists to look for producing and using catalysts which not only cause pollution and toxicity in the reactions and products, but also generate economical benefits. Our goal in this paper is to produce a fully biocompatible, non-toxic and inexpensive carbocatalyst with a graphene oxide structure for use in multi-component reactions as a heterogeneous catalyst. The research has been carried out to simplify the method of preparing carbocatalysts. In this article, we heated citric acid and thiourea in the simple bottom-up method in which nitrogen and sulfur were atomically inserted into a carbon-carbon bond of graphene oxide. The results have been obtained by comparing graphene oxide quantum dots (GOQDs) and functional graphene oxide quantum dots (GOQDs) and functional nitrogen and sulfur-doped graphene oxide quantum dots (NS-doped-GOQDS) using the produced carbocatalyst in the synthesis of spiro indoline pyrano pyrazoles and highly substituted pyridine derivatives with chemical and pharmacological properties. A simple and affordable bottom-up method has been developed to synthesize fluorescent NS-doped-GOQDS by the condensation of CA in the presence of thiourea with water elimination at 185 ℃. After the production of NS-doped-GOQDS, the carbocatalyst is used in the synthesis of spiro[indoline-3,4'-pyrano [2, 3-c]pyrazole] derivatives in four-component reactions and pyridine derivatives in five-component reactions.

Revolutionizing regeneration of NADH and deoxygenation of sulfide: Harnessing visible light with SDG@TPP composites for powerful synthetic applications

Aqueous ascorbic acid splitting through photocatalysis is a potential method for turning solar energy into value-added compounds. As a result, converting solar light into green solar fine chemicals in an ecologically responsible and cost-effective manner remains a difficult issue. The solvothermal approach was used to effectively construct an SDG@TPP composite photocatalyst.To that end, we present here the synthesis and development of a sulfur-doped graphene (SDG)-based visible light active composite photocatalyst (SDG@TPP), in which SDG interacts with TPP (tetraphenyl porphyrin) through - stacking. Due to its high molar extinction coefficient and delayed recombination features, the newly manufactured SDG@TPP photocatalyst acts in a highly effective way, resulting in higher NADH regeneration (66.1 %) and sulfoxide deoxygenation than SDG photocatalyst. More importantly, a little quantity of TPP on the surface of SDG can efficiently stimulate photoelectron injection and improved photocatalytic activity. This research should shed light on how to create metal-free SDG@TPP composites with good solar energy conversion.

Three-Dimensional Architecture of Sulfur Doped Graphene for Supercapacitor

The introduction of heteroatoms is beneficial to prevent the stacking of graphene and enhance the electrochemical performance of graphene-based electrode materials. In this work, the three-dimensional structure sulfur-doped graphene (SG) electrode materials were prepared by using PEDOT:PSS as sulfur source, which can form a polymer chain on the surface of the graphene oxide, thus the sulfur atoms can be successfully doped into the graphene lattice by annealing treatment. The obtained SG electrode material exhibits a high specific capacitance of 254 F g−1 at 0.5 A g−1, which is significantly better than that of the pure reduced graphene oxide. The significant increase in specific capacitance confirms that sulfur-doped graphene has a promising future in supercapacitor applications.

Adsorption and gas-sensing investigation of oil dissolved gases onto nitrogen and sulfur doped graphene quantum dots

Burning hydrocarbons as fuel, which produces carbon dioxide and water, is a major contributor to anthropogenic global warming. Hydrocarbons are introduced into the environment through their extensive use as fuels and chemicals as well as through leaks or accidental spills during exploration, production, refining, or transport of fossil fuels. Herein, theoretical calculations based on density functional theory (DFT) was applied to investigate the adsorption behavior of C2H4, CH4 and H2 on graphene quantum dot surfaces doped with Nitrogen (N) and sulfur (S) (GQD_N, GQD_S). Theoretical calculations in this study were obtained with the dispersion correction in consideration so as to predict intermolecular interactions alongside B3LYP-D3(BJ)/6-311+G (d, p). The sites that were doped with N and S atom were found to be more stable and suitable for gas adsorption. The adsorption energy was computed to establish the surface abilities of the adsorptions under investigation. Gas adsorptions on surfaces showed similar high negative values. We may deduce from the computed adsorption energies that GQD_N and GQD_S have strong adsorptions and considered adsorptions are thermodynamically favored. The ellipticity parameter calculated using the quantum theory of atoms in molecules (QTAIM), as well as the stabilization energies obtained from natural bond orbitals (NBO), confirmed the stability of surfaces upon gas adsorptions. QTAIM also confirmed remarkable intermolecular interactions. This result also agrees with that for non-covalent interactions, which predicted weak intermolecular interactions between surface and gas molecules. GQD_N and GQD_S are good adsorbents that can adsorb C2H4, CH4, and H2 gases, respectively.

S-Doped Graphene Oxide/N-Doped Graphene Oxide/PANI: A Triple Composite for High-Performance Supercapacitor Applications

In this study, nitrogen doped graphene oxide(N-GO) and sulfur doped graphene oxide(S-GO) were produced in one step, and two of these prepared materials were converted into composite form with polyaniline(PANI). For the first time in the literature, triple composite electrode materials with two heteroatom doped graphene oxides and PANI were prepared for supercapacitors. In this context, heteroatom doped graphene oxides and PANI were characterized using spectroscopic and microscopic methods. With the ternary composites formed, anode and cathode electrode materials for coin cell type supercapacitors in asymmetrical form were characterized by electrochemical methods. The capacitive behavior of the prepared supercapacitors was investigated by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) method. The change of capacitive behavior according to the number of cycles was determined by cyclic charge-discharge tests. With the electrode materials obtained with heteroatom doped graphene oxides/PANI composites, it reached the highest areal capacitance value of 79.7 mF.cm−2 at 10 mV.s−1 scan rate. The coin cell type asymmetric supercapacitors retained more than 100% of their initial specific capacitance at the end of the 1500 cycle.

Rationally incorporated SnO2/SnS2 nanoparticles on sulfur-doped graphene aerogels for high-performance lithium/sodium-ion batteries

Tin-based anode materials, such as tin oxide and tin sulfide, have received increased attention due to their high theoretical capacity, natural abundance, and adequate operating voltage. But the large volume variation and sluggish reaction kinetics lead to severe structural deterioration and capacity fading during the charge-discharge process, hindering their practical application. Herein, we synthesized a unique ternary hybrid structure to grow SnS2 nanosheets and SnO2 particles on graphene aerogels by hydrothermal method (denoted as SnO2/SnS2/SGA). The SnO2/SnS2/SGA exhibited better cycling stability than SnS2/GA and SnO2/GA. The tight adhesion of SnO2/SnS2 helps to alleviate the undesired electrode materials destruction due to volume expansion. Furthermore, SnO2 and SnS2 quantum dots anchored on graphene aerogels can undergo reversible conversion reaction that profit by synergistic effect. The reversibility of the SnO2/SnS2/SGA material during the transition was also proved by ex-situ high-resolution transmission electron microscopy. The SnO2/SnS2/SGA hybrid was endowed with enhanced electrochemical capability.

Capture-reduction mechanism for promoting Cr(VI) removal by sulfidated microscale zerovalent iron/sulfur-doped graphene-like biochar composite

The application of microscale zerovalent iron (mZVI) in the removal of Cr(VI) from water is plagued with the readily formation of oxide passivation layer. In this study, we propose a “capture-reduction” mechanism to enhance the Cr(VI) removal performance of mZVI under anaerobic condition through dual modification, i.e., sulfidation and construction of composite with sulfur-doped graphene like biochar (SGB). The S-mZVI/SGB has a Cr(VI) removal capacity of 70.2 mg·g− 1 at circumneutral pH, which is 56 times of that of mZVI. The 1,10-phenanthroline shielding experiments indicate that the contribution of Fe(II) to Cr(VI) removal is only 17.6%. Density-theory-functional (DFT) calculation results indicate that sulfur doping could significantly promote the adsorption of Cr(VI) on SGB nanosheets. The mechanism study confirmed the “capture-reduction” Cr(VI) removal mechanism, whereby the SGB nanosheets capture Cr(VI) ions and receive electrons from Fe0 to reduce Cr(VI) to Cr(III). Considering its advantages such as low cost and easy preparation, the S-mZVI/SGB composite is a promising green material for the removal of Cr(VI) from water.Graphical

Negative Thermal Expansion of Sulphur-Doped Graphene Oxide

The sulfur content present in graphene oxide prepared by Hummers' method has only been addressed by few papers so far. By modified Hammers method we synthesized thermally stable in ambient environment multilayer sulphur-doped graphene oxide. The samples were heat treated in an electrical furnace setup at different ambient temperatures and their crystallite size and linear coefficient of thermal expansion were extracted from Raman band intensity peak ratio as a function of temperature. We found unusually large (in comparison with graphene oxide) contraction on heating of multilayer two weight percent sulphur-doped graphene oxide with carbon to oxygen ratio of 2.3 in a narrow temperature range (308-318 K) with the lowest value of the linear thermal expansion coefficient of -18 ppm 1/K. Based upon an examination of the synthesized sulphur-doped graphene diffractograms, it is suggested that negative thermal expansion stems from the phonon backscattering by the sulphur impurity sites and the edges of the layers. The obtained experimental results have potential practical applications for fabrication of solar cells, sensors, lubricators, thermal actuators and also wavelike (second sound) thermal transport structures.

Heteroatom-doped graphene oxide-based conductive ink: synthesis, characterization and investigation of the conductivity properties for flexible sensor technology

In this study, a conductive ink containing sulfur-doped graphene oxide, polyvinylidene fluoride, and N-methyl-2-pyrrolidone was synthesized and was coated on a polyester/cotton blended fabric substrate by the “dip and dry” method.

Nitrogen- and sulfur-doped graphene quantum dots for chemiluminescence.

Graphene quantum dots (GQDs), as one of the most promising luminescent nanomaterials, have been receiving increasing attention in various applications. However, it is still a challenge to improve their chemiluminescence (CL) quantum efficiency. Herein, the CL emissions of nitrogen- and sulfur-doped GQDs (NS-GQDs), nitrogen-doped GQDs (N-GQDs) and undoped GQDs synthesized through one-pot high-temperature pyrolysis are investigated in their chemical reactions with bis(2-carbopentyloxy-3,5,6-trichlorophenyl) oxalate (CPPO) and hydrogen peroxide (H2O2). A bright blue emission, and yellowish green and yellowish white light from NS-GQDs, N-GQDs and GQDs can be observed, respectively, in the mixture solutions with CPPO and H2O2. For the first time, spooling CL spectroscopy was used to investigate the CL reaction mechanisms, illuminant decays and the absolute CL efficiencies of these three GQD systems. Compared with the same system of undoped GQDs, it has been found that the NS-GQDs not only present slower illuminant decay, but also display an absolute CL quantum efficiency of 0.01%, 5-fold enhancement, due to the increase in N and S doping for a well-defined band gap energy. Moreover, three peak wavelengths attributed to intrinsic emission at 425 nm, aggregation-induced emission (AIE) at 575 nm and S-doped emissive surface states at 820 nm are observed for the first time in the NS-GQD system. The CL spectrum of N-GQDs displays two emission peaks at 395 and 575 nm attributed to intrinsic emission and AIE, whereas the CL spectrum of undoped GQDs demonstrates 500 nm and 600 nm peak wavelengths attributed to core emission and AIE. Absolute CL quantum efficiencies from these emissions at these various peaks can be determined quantitatively. This study provides guidance on tuning the surface states of GQD for more conducive injection of electrons and holes, facilitating the production of CL emission, which is beneficial for promoting the development of optical, bioassay and energy conversion applications.