In order to optimize the manufacturing of polypropylene-derived few-layer graphene, an innovative utilization of nonsupported iron oxide nanoparticles generated under various fuel environment conditions was studied. Three distinct fuel combustion environment circumstances (fusion, fuel shortage, and fuel excess) produced a variety of Fe2O3 nanoparticles for cost-effective and green graphene deposition. XRD, H2- TPR, Raman, and TGA measurements were used to characterize both new and spent catalysts. Remarkably, the microstructure of the generated Fe2O3 nanoparticles could be controlled by the citric acid/iron nitrate ratio, ranging from spheroids ( Fe2O3(0)) to sheets ( Fe2O3(0.5-0.75)) and a hybrid microstructure that consists of sheets, spheroids, and interconnected strips ( Fe2O3(1-2)). According to fuel situation (citric acid/iron nitrate ratio, Fe2O3( 0-2)), various graphitization level and yields of graphene derivatives including sheets, ribbons, and onions have been developed. With the ideal fuel/oxidant ratio (ɸ = 1), the Fe2O3( 0.75) catalyst demonstrated the best catalytic activity to deposit the largest yield of highly graphitized few graphene layers (280%). Lean and rich fuel conditions (1 > ɸ > 1) have detrimental effects on the amount and quality of graphene deposition. It is interesting to note that in addition to graphene sheets, an excess of citric acid caused the production of metallic cores, hollow, and merged carbon nano-onions, and graphene nano-ribbons. It was suggested that carbon nano-onions be converted into graphene nano-ribbons and semi-onion shell-like graphene layers.

To improve the proton conductivity of the proton exchange membranes (PEM), an amino derivative with sulfonic acid groups was used to modify graphene oxide (GO), resulting in sulfonated graphene oxide (S-GO), which was then incorporated into a perfluorinated sulfonic acid (PFSA) matrix to fabricate a PFSA/S-GO composite membranes. Elevating the doping concentration of S-GO within the composite membrane has resulted in enhanced proton conductivity, outperforming the baseline PFSA membrane across a range of temperatures. Notably, this conductivity ascended to 291.89 mS/cm when measured at 80 °C under conditions of 100% RH. Furthermore, the strong interface interaction between sulfonated graphene oxide and perfluorinated sulfonic acid polymer endowed the composite proton exchange membrane with excellent thermal stability and mechanical strength.

This research developed a highly efficient voltammetric sensor, utilizing a carbon paste electrode (CPE) integrated with a novel ZnO-doped Pd–Pt bimetallic catalyst decorated with reduced graphene oxide (ZnO-Pt@Pd/rGO) and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([EMIM][Tf2N]), for the precise determination of sulfafurazole in real dextrose saline and tablet samples. The ZnO-Pt@Pd/rGO nanocomposite was synthesized through a one-stage synthesis process and characterized using SEM and EDS techniques. The comparison of the ZnO-Pt@Pd/rGO/[EMIM][Tf2N]/CPE with unmodified CPE, ZnO-Pt@Pd/rGO/CPE, and [EMIM][Tf2N]/CPE confirms the synergic effect of ZnO-Pt@Pd/rGO and [EMIM][Tf2N] as two conductive catalysts in fabrication of new sensor. The resulting sensor exhibited remarkable stability over a period of 2 months without compromising its efficiency for sulfafurazole detection. With a linear range of 0.001–250 μM (R2 = 0.9971) and LOD of 0.4 nM, ZnO-Pt@Pd/rGO/[EMIM][Tf2N]/CPE showcased exceptional accuracy and precision in the monitoring of sulfafurazole. Validation using real tablet and dextrose saline samples confirmed the sensor's outstanding capability in determining sulfafurazole, with relative recoveries ranging from 98.92 to 103.8% offering a promising solution for reliable sulfafurazole analysis in diverse pharmaceutical samples.

Polypropylene waste significantly contributes to environmental pollution due to its low biodegradability. Numerous experiments have shown that laser irradiation of polymers can lead to the conversion of laser-induced graphene (LIG). In this paper, the LIG formation process in polypropylene (PP), polydimethylsiloxane (PDMS), and polypropylene/polydimethylsiloxane (PP/PDMS) systems in a vacuum environment was simulated using molecular dynamics. The LIG yields and carbon network sizes of the systems in oxygen and vacuum environments at different temperatures were analyzed to determine the optimal temperature for upgrading PP to LIG. It was observed in all three systems that the LIG structure was formed. The structure was composed not only of six-membered carbon rings, but also of five-membered and seven-membered rings, resulting in out-of-plane fluctuations and bending. A vacuum environment and high temperature promote LIG formation with high yield, large size, and minimal defects. The current study provides theoretical guidance for optimizing the laser graphene process for PP assisted with PDMS in a vacuum environment and helps to understand the mechanism underlying the conversion from polyolefins to graphene under CO2 laser at the atomic level.

Self-assembled organic layers containing various functional groups between graphene layers were examined as gas barrier films. The formation of well-defined self-assembled layers of functionalized alkane molecules on graphene was confirmed by scanning tunneling microscopy (STM). The roles of these organic layers as gas barrier films could be quantitatively deduced by comparing their water vapor transmission rate (WVTR). The formation of self-assembled layers dramatically improved gas barrier properties by primarily blocking defects and gas molecule pathways. For functionalized alkanes containing hydrophilic groups, more enhanced gas barrier properties were observed compared to those with hydrophobic groups. These results clearly indicate that the primary role of the organic layers in gas barrier films is to block defects and the pathways of water molecules, with a secondary role of delaying the movement of water molecules through hydrogen bonding interactions.

In this study, we developed electrochemical sensors based on the composite of hydroxylated multiwalled carbon nanotubes (MWCNT-OH) and graphene for paraoxon-ethyl detection as pesticide residues in agricultural products. Chemical treatment was employed to produce MWCNT-OH from pristine MWCNT and its composite with graphene was subsequently characterized using FTIR, Raman spectroscopy, FESEM-EDX, TEM, and XPS techniques. The MWCNT-OH/graphene composite was employed as an electrode modifier on the glassy carbon electrode (GCE) surface, and its electroanalytical performances were studied using differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) techniques. It was revealed the optimum composition ratio between MWCNT-OH and graphene was 2:8, for paraoxon-ethyl detection at pH 7. This could be attributed to the enhanced electrocatalytic activity in the MWCNT-OH/graphene composite which displayed a linear range of paraoxon-ethyl concentration as 0.1–100 μM with a lower detection limit of 10 nM and a good sensitivity of 1.60 μA μM cm− 2. In addition, the proposed sensor shows good reproducibility, stability, and selectivity in the presence of 10 different interfering compounds including other pesticides. Ultimately, this proposed sensor was tested to determine the paraoxon-ethyl concentrations in green apples and cabbage as samples of agricultural products. The obtained concentrations of paraoxon-ethyl from this proposed sensor show no significant difference with standard spectrophotometric techniques suggesting this sensing platform might be further developed as a rapid detection of pesticide residue in agricultural products.

Efforts to mass-produce high-quality graphene sheets are crucial for advancing its practical and industrial applications across various fields. In this study, we present an innovative electrochemical exfoliation method designed to enhance graphene quality and increase yield. Our approach combines two key techniques: expanding the tightly packed graphite interlayer used as the electrode medium and precisely controlling voltage polarity. The dual-exfoliation technique optimizes the use of anions and cations of varying sizes in the electrolyte to facilitate meticulous intercalation, allowing ions to penetrate deeply and evenly into the graphite interlayer. The newly designed dual-exfoliation technique using biased switching polarity minimizes the generation of oxygen-containing radicals, while the incorporation of expanded graphite accelerates exfoliation speed and reduces oxidation, maintaining high graphene purity. With these improvements, we produced 1–3 layer graphene sheets with minimal defects ( ID/IG ≈ 0.13) and high purity (C/O ratio ≈ 20.51), achieving a yield 3.1 times larger than previously reported methods. The graphene sheets also demonstrated excellent electrochemical properties in a three-electrode system, with an electrical conductivity of 92.6 S cm− 1, a specific capacitance of 207.4 F g− 1, and a retention of 94.8% after 5,000 charge/discharge cycles, highlighting their superior stability and performance.

This study introduces a cost-effective electrochemical exfoliation technique for producing highly crystalline graphene from graphite. By optimizing key exfoliation parameters, including voltage, electrolyte concentration, and temperature, the efficiency of the exfoliation process and the quality of the resulting graphene were significantly improved. To further enhance crystallinity, minimize defect sites, and achieve superior material properties, the as-prepared electrochemically exfoliated graphene (AeEG) underwent post-heat treatment at temperatures ranging from 1500 to 2950 °C. When employed as a conductive additive, eEGs heat-treated at 1800 °C or higher significantly improved both cycle stability and rate performance in LIB coin cells, while maintaining a discharge capacity approximately 10–12 mAh/g higher than that of the control, which utilized Super P. The enhanced performance is attributed to the formation of an efficient conductive network and superior electron transport properties, driven by the high crystallinity and large aspect ratios of the heat-treated eEGs. These findings highlight the potential of eEG as a highly effective conductive additive for advanced battery industries, offering significant improvements in energy storage performance, specific capacity, and rate characteristics.

Graphene quantum dots have recently gained significant attention for their potential application in the development of optoelectronic materials. The present study focused on the ultrasonic method to synthesize white-light-emitting graphene quantum dots from coal soot in just 2 min at room temperature. The white-light emission was achieved in solution and polymeric film with good Commission Internationale del’Eclairage index (0.28, 0.33) and (0.25, 0.30), respectively. The graphene quantum dots cover a significant fraction of the visible region in the emission spectrum with two prominent bands at 475 and 635 nm at 380 nm photoexcitation, corresponding to monomer and J-aggregate emission. The strong reducing and basic nature of the ethylene diamine facilitated the preparation of self-assembled J-aggregate graphene quantum dots through hydrogen bonding and electrostatic interaction. The mechanism of origin J-aggregate emission in the prepared graphene quantum dots was studied using UV–visible absorption, steady-state, lifetime fluorescence spectroscopy, and zeta potential. The as-synthesized graphene quantum dots are successfully coated on the UV-LEDs' surface and emit white light on the applied voltage. The colours of red, green, blue, and yellow balls appear significantly in the lighting of prepared white LEDs.

The growing demand for clean energy and sustainable technologies has intensified the need for efficient energy storage systems (EES) that support renewable energy integration while minimizing environmental impact. Biomass, an abundant and renewable resource, presents a cost-effective and eco-friendly pathway for producing advanced carbon materials, particularly heteroatom-doped graphene derivatives. This transformation aligns with circular economy principles by converting waste streams into high-performance materials for EES applications. This review provides a comprehensive analysis of biomassderived heteroatom-doped graphene materials, focusing on their synthesis, properties, and applications in electrochemical energy storage systems. It addresses a critical gap in the literature by systematically examining the relationship between biomass sources, doping strategies, and their impact on graphene’s electrochemical performance. The study highlights the role of heteroatom doping such as nitrogen, sulfur, phosphorus, and boron in enhancing graphene’s structural and electronic properties. These modifications introduce active sites, improve conductivity, and facilitate ion storage and transport, resulting in superior energy density, cycling stability, and charge–discharge performance in devices such as sodium/lithium-ion batteries, lithium-sulfur batteries, supercapacitors, and fuel cells. Recent advancements in green synthesis methods, including pyrolysis, hydrothermal carbonization, and chemical activation, are highlighted, focusing on their scalability and resource efficiency. By addressing both environmental and technological benefits, this review bridges the gap between laboratory research and practical applications. It underscores the critical role of biomass-derived graphene in achieving sustainable energy solutions and advancing the circular economy, offering a roadmap for future innovations in this rapidly evolving field.