Incorporating nanotechnology into cement composites significantly improves mechanical properties such as strength, toughness, and durability. Graphene, with high tensile strength and large surface area, shows great promise as a nanofiller, but its hydrophobicity complicates its dispersion in cement matrices. This study used a graphene-cellulose nanofiber (G@ CNF) hybrid filler to ensure a highly uniform dispersion within the cement microstructure. The hybrid filler acts as a bridge and efficiently fills voids within the matrix. The planar structure of graphene also provides nucleation sites for hydrated products, leading to a denser microstructure. The cement composite containing 0.01 wt.% graphene exhibited a compressive strength of 72.7 MPa, representing a 47.5% improvement over the plain cement. Furthermore, the resulting cement demonstrated enhanced water resistance compared to graphene oxide-reinforced-cement. This approach offers a cost-effective and sustainable way of producing high-strength, durable cement composite.

In this study, GNPs/FeCoNiCuAl particles synergistically reinforced aluminum matrix composites are developed by friction stir processing (FSP) to explore the effects of different GNPs contents (1, 3, and 5%) on the microstructure, mechanical performance, and wear resistance of the materials. The results show that the incorporation of GNPs affects the formation of the diffusion layer between the FeCoNiCuAl particles and the aluminum matrix. As the content of GNPs increases, the thickness and integrity of the diffusion layer between FeCoNiCuAl particles and aluminum matrix gradually decrease. In addition, the introduction of GNPs is beneficial in enhancing the proportion of high-angle grain boundaries in the composites, but the grain size of the specimen increases slightly to about 5.5 μm at a content of 5% GNPs. When the content of GNPs is 1%, the composites achieve the highest microhardness and the lowest specific wear rate (0.1459 × 10⁻⁶ mm3/ N·m), with the wear mechanism dominated by abrasive wear. Nonetheless, when the GNPs content in the composite increases to 5%, the thickness and integrity of the diffusion layer are minimal, causing the tensile strength of the composite to be reduced to 250 MPa, and the specific wear rate increased to 0.4244 × 10– 6 ( mm3/N·m), with the wear mechanism transformed to abrasive–adhesive mixed wear. This study demonstrates that the appropriate ratio of GNPs and FeCoNiCuAl particles can effectively enhance the mechanical and wear resistance properties of aluminum matrix composites, providing a theoretical basis for the design and development of high-performance aluminum matrix composites.

This study explores the electrochemical modification of reduced graphene oxide (rGO) by incorporating 1,10-phenanthroline groups prior to the electrodeposition of silver nanoparticles (Ag NPs), aiming to enhance the performance on the oxygen reduction reaction (ORR). The introduction of 1,10-phenanthroline onto the rGO surface significantly improved its ability to coordinate metallic cations, compared to unmodified rGO. This enhanced coordination capacity led to a more efficient deposition of Ag NPs. Notably, increasing the amount of 1,10-phenanthroline groups grafted onto the rGO further boosted the number of deposited Ag NPs, substantially improving ORR performance. These results demonstrate that increasing the number of coordination units on rGO sheets prior to metal incorporation can significantly enhance the electrocatalytic efficiency of the resulting nanocomposites. This work emphasizes the importance of functionalizing rGO surfaces to optimize their catalytic properties for energy conversion and storage applications. This modification of rGO also paves the way for broader potential applications across various fields.

Recent advancements in 2D graphene materials highlight their versatile applications in electronics, clean energy, medicine, and other fields due to their exceptional properties and ease of fabrication. The current study investigates the preparation of reduced graphene oxide (RGO) through the thermal exfoliation of graphite oxide under an air atmosphere at varying temperatures (200–500 °C) and further examines its suitability as an anode for lithium-ion (Li-ion) batteries. The extent of reduction of functional groups, exfoliation, and other physical changes is analyzed by XRD, SEM, XPS, BET, and Raman studies, which show that the reduction of functional groups and surface area increases with increasing exfoliation temperature. The RGO electrodes are subjected to electrochemical studies, including cyclic voltammetry and charge–discharge cycling at various current densities, which demonstrate varying discharge capacities for RGO samples prepared at different temperatures. The RGO exfoliated at 400 °C delivered the maximum capacity, indicating that this temperature is optimal for the thermal preparation of RGO. This material shows potential for use as an anode in Li-ion batteries.

Graphene materials show great potential in the field of supercapacitors, but their tendency to agglomerate leads to a significant decrease in performance. Herein, manganese dioxide intercalated graphene oxide precursor was prepared using the modified Hummer method. During pyrolysis, manganese dioxide can not only act as a separator to prevent graphene aggregation but also undergo redox reactions with graphene to obtain oxygen-rich mesopore graphene (OMG). Benefiting from the mesoporous structure and abundant oxygen-containing functional groups, the OMG-600 electrode shows a specific capacitance of 248.67 F g− 1 at 0.5 A g− 1 and good electrochemical stability (92.25% capacitance retention after 10,000 cycles). Moreover, the assembled OMG-600//OMG-600 symmetric supercapacitor delivers an energy density of 17.69 Wh kg− 1 and superior electrochemical stabilization in 1 M Na2SO4 electrolyte.

With high redox activity, superior conductivity, abundant pores, and large specific surface area, nitrogen-doped graphitic carbon featuring a hierarchically porous structure is regarded as ideal electrode material for supercapacitors. In this work, hierarchically porous nitrogen-doped graphitic carbon (PG-PZC50) was fabricated via non-solvent induced phase separation and high-temperature calcination processes. SEM images showed its three-dimensional network structure, with abundant macro- and mesopores distributed throughout. XRD and Raman spectra confirmed the phase purity and graphitic nature of the as-prepared material, while XPS revealed its surface elemental composition, especially the content and doping states of nitrogen atoms. The graphene oxide-induced three-dimensional network, combined with the mesoporous structure of metalorganic framework-derived N-doped carbon particles, creates abundant migration channels and a large adsorption surface area for the electrolyte ions. Benefiting from its hierarchically porous structure and high nitrogen-doping content, the formed PG-PZC50 reached high specific capacitances of 499.7 F g− 1 at 0.1 A g− 1 and 179.6 F g− 1 at 20 A g− 1. Notably, the material also demonstrated robust cyclic stability with no capacitance loss after 10,000 charge–discharge cycles. The proposed synthetic strategy provides new ideas for the facile and reproducible construction of nitrogen-doped graphitic carbon with 3D hierarchically porous structure and high capacitive performances.

With the increasing demand for flexible electronic devices, smaller and lighter flexible supercapacitors have gained significant research attention. Among the various materials, self-supporting reduced graphene oxide (rGO) paper has emerged as one of the most promising electrode materials for supercapacitors due to its low cost, high chemical/thermal stability, and excellent electrical conductivity. Nevertheless, a major drawback of rGO paper is the limited ion diffusion between stacked rGO layers, hindering the effective formation of electrochemical double-layer at the electrode/electrolyte interface. In this study, we prepared the rGO paper derived from ball-milled followed-by water oxidation process for reducing the sheet size. The smaller-sized rGO sheets facilitated ion transport between graphene layers, promoting efficient electric double-layer formation. Moreover, the increased presence of edge planes in ball-milled rGO sheets achieved high capacitance, further enhancing the performance of rGO as an electrode material. Notably, the 2-BMOX rGO paper obtained from ball-milling and wet-oxidized graphite exhibited a capacitance of 117.9 F/g in cyclic voltammetry (CV) and 128.6 F/g in galvanostatic charge–discharge (GCD) tests, approximately twice that of conventional rGO. Additionally, the capacitance retained 91% of its initial performance after 2,000 cycles, indicating excellent cycling stability.

Improving the oxygen evolution reaction (OER) performance or replacing OER with the value-added conversion of biomass is of great significance for the green hydrogen energy production. In this work, bimetallic species-decorated laser-induced graphene (LIG) was fabricated and demonstrated as the self-supported electrodes towards efficient OER and 5-hydroxymethylfurfural oxidation reaction (HMFOR). Three-dimensional LIG was obtained via one-step irradiation process under ambient conditions, and active metal species were then introduced through electrodeposition, with Ni-based catalyst as the primary catalytic material and Fe and Co as modified metals. Among, LIG-NiFe electrode achieved an extremely low overpotential of 241.7 mV at a current density of 20 mA/cm2 for OER and demonstrated long-term stability. This could be attributed to the promoted formation of Ni3+ active centers by Fe modified and the intrinsic porous structure of LIG providing an enhanced surface area. As for LIG-NiCo, due to the low onset potential of Co for HMF, it could achieve 99.6% HMF conversion and yielded value-added 2, 5-furandicarboxylic acid (FDCA) with a selectivity of 87.1%. Coupled with the merit of facile fabrication of LIG framework, this study demonstrates that LIG-based electrodes assume great practical application value in electrocatalytic reactions.

A flexible heater with high thermal efficiency and mechanical durability was developed by fabricating laser-induced porous graphene (LIPG) electrodes on polyimide films using a 532 nm green laser. Laser power, scan speed, and line distance were precisely optimized based on photothermal simulations to generate uniform porous graphene structures with large surface area and excellent heat dissipation characteristics. Raman, X-ray diffraction, and X-ray photoelectron spectroscopy analyses confirmed that the optimized LIPG exhibited highly graphitized features with low oxygen defects. Scanning electron microscope analysis revealed that porous morphologies formed only within a specific laser scan speed range, whereas excessive or insufficient irradiation resulted in collapsed or absent porosity. The serpentine-patterned LIPG heater maintained stable electrical resistance under repeated multidirectional bending, demonstrating excellent flexibility and mechanical stability. The heater also achieved rapid and uniform heating up to 80 °C within seconds, maintaining consistent temperature distribution even on curved surfaces.

본 논문은 그래핀 혈소판(GPL)으로 보강되고 내부 균열을 가진 원통 복합 구조물에 대한 임계 좌굴하중의 수치적 고찰을 다루고 있다. 임계 좌굴하중을 정확하게 평가하기 위해 이차원 자연요소법(NEM) 기반으로 개발한 효과적인 위상필드 균열모델을 제시하였 다. 그래핀 혈소판은 두께방향으로 특정한 기능적 분포패턴으로 원통형 구조물에 삽입되어 있다. 수치적으로 균열의 존재를 표현하 는 전통적인 절점분리 기법은 모델링의 번거로움은 물론 수치적 불안정성을 야기할 수 있다. 이러한 문제점을 극복하기 위해 본 논문 에서의 위상필드 정식화에서는 수치 그리드의 복잡한 작업 없이 위상 필드를 도입하여 균열을 표현하였다. 개발된 수치기법의 안정 성과 신뢰성은 그리드 밀도에 따른 수렴성과 참고문헌과의 비교를 통해 입증하였으며, 그래핀이 보강된 원통 복합재의 좌굴특성을 관련된 주요 인자들에 따른 파라메트릭 수치실험을 통해 고찰하였다.

본 연구에서는 그래핀 나노플레이트(GNPs)가 혼입된 모르타르의 기계적 및 전기적 특성을 보통 포틀랜드 시멘트(OPC)와 비교하여 체계적으로 분석하였다. 시멘트 대비 0.1 wt.%의 GNPs를 첨가한 결과, 28일 양생 시 압축강도가 약 12% 증가하였으며, 7일 초기 재령에서 휨강도는 약 50% 향상되었다. 또한 GNPs가 혼입된 모르타르는 연속적이고 균일한 전도성 네트워크를 형성하여, OPC에 비해 약 49% 높은 전기전도도를 나타냈다. 열중량-미분열중량(TG–DTG) 분석 결과, GNPs의 도입이 핵생성 부위를 증가시키 고 C–S–H(Calcium Silicate Hydrate) 구조 생성을 촉진함으로써 시멘트의 수화 반응 속도를 향상시키는 것으로 확인되었다. 이러한 결과는 GNPs가 수화 반응 촉진과 미세균열 가교(micro-crack bridging) 역할을 통해 모르타르의 기계적 특성을 개선함과 동시에, 재료를 반도전성 복합체(semi-conductive composite)로 전환시킨다는 것을 보여준다.

본 연구에서는 과불화 알킬 사슬이 도입된 산화 그래핀(perfluoroalkyl-grafted graphene oxide, FGO)을 합성하고, 이를 과불소화계 고분자인 나피온(Nafion)에 복합화하여 바나듐 레독스 흐름 전지(vanadium redox flow battery, VRFB)용 이 온 교환 막을 개발하고자 하였다. FGO는 염기성 촉매 하에서 카르복실산기를 함유한 폴리(헥사플루오로프로필렌 옥사이드) (157 FSL, DuPont)의 카르복실산기와 GO의 에폭시기 간 개환 에스터화 반응을 통해 합성하였다. 합성된 FGO를 Nafion 기 지체에 함량을 달리하여 첨가한 복합막(N/FGO_X)을 제조하고, 함수율, 체적 안정성, 수소 이온 전도도, 바나듐 이온 투과도 및 셀 성능을 평가하였다. N/FGO 복합막은 Nafion 단일막 대비 낮은 함수율과 체적 변화율을 보였으며, FGO의 물리적 차단 효과에 의해 바나듐 이온 투과도가 감소하면서도 수소 이온 전도도를 유지하여 우수한 이온 선택도를 나타내었다. VRFB 단 위 셀 평가 결과, FGO가 도입된 복합막은 Nafion 단일막을 적용한 셀 대비 높은 방전 용량, 쿨롱 효율 및 에너지 효율을 유 지하였다.

Laser-induced graphene (LIG) has emerged as a promising carbon nanomaterial platform owing to its scalability and tunable surface properties. Although its electrical and structural characteristics have been widely explored, the precise modulation of the surface energy remains challenging, particularly in ultrathin configurations. In this study, we investigated the wetting behavior of an ultrathin LIG synthesized from a fluorinated polyimide (F-PI) thin-film precursor using ultraviolet (UV) laser irradiation. Systematic variations in laser exposure induced morphologic transitions from hierarchical porous networks to compact planar structures, accompanied by changes in the chemical composition, including fluorine depletion and oxygen incorporation. These combined effects result in a broad range of wetting behaviors, including superhydrophobicity and hydrophilicity. Remarkably, LIG produced under single irradiation exhibited a rose-petal-like wetting state characterized by a high contact angle and strong droplet adhesion, a phenomenon not previously reported in LIG systems. This work elucidates the interplay between laser-induced nanostructuring and surface chemistry in governing wetting behavior and establishes a controllable strategy for fabricating functional carbon surfaces for applications in microfluidics, selective adhesion, and water-repellent coating technologies.

This study investigates the sustainable synthesis of biobased graphene (BG) derived from coconut husk waste and its application in eco-friendly water-based drilling muds (WBM). The BG was prepared through thermal exfoliation of lignin and utilized as a fluid loss additive, while benzimidazole (BI) was incorporated to serve as a corrosion inhibitor. To optimize performance, the Taguchi method was combined with Grey Relational Analysis (GRA), targeting three key parameters: viscosity, fluid loss, and corrosion resistance. Structural characterization revealed that BG synthesized at 1000 °C exhibited improved graphitic ordering, with an average flake diameter of around 20 nm and an interlayer spacing (d-spacing) of 3.49 Å. In terms of performance, incorporating 0.5 wt% BG reduced fluid loss by 50%, while 5 wt% BI delivered an impressive corrosion inhibition efficiency of 96.9%. The optimal mud formulation was achieved using 0.5 wt% BG, 5 wt% BI, 60 min of mixing time, and 8 wt% bentonite. Altogether, this work highlights a sustainable pathway for drilling fluid formulation by valorizing agricultural waste and minimizing additive loadings—without compromising on performance or environmental compatibility.

The avenue to synthesize eco-friendly and high-performing warm-white light emitting diodes (WLEDs) using quantum-dots for color conversion is challenging. Here, the graphene quantum dots (GQDs) are synthesized from Moringa oleifera leaves without the need of any organic solvents or reducing agents by a one-pot hydrothermal method and utilized for the design of efficient warm WLEDs. The photoluminescence of the obtained GQDs is found to be red-shifted as the excitation wavelength increases. This is ascribed to an excitation of multiple transitions due to various surface traps related to surface amino and oxygen functionalized groups as revealed from X-ray-photoelectron–spectroscopy and FTIR results. Three different concentrations of GQDs are embedded in polyvinyl-alcohol matrix acting as color-converters for the design of WLED devices. By increasing the GQDs concentration, the color correlated temperatures are tuned from 3804 to 2593 K and the luminous efficacy from 39.3 to 71.69 lm/W. Moreover, the chromaticity coordinates of the devices are shifted from (0.3825, 0.3665) to (0.4807, 0.4478). The brightness of the fabricated devices based on these green-GQDs are comparable with those of warm LEDs prepared from chemically synthesized graphene and carbon dots and can be suitable for indoor lighting applications.

The distinctive surface characteristics of two-dimensional(2D) materials present a significant challenge when developing heterostructures for electronic or optoelectronic devices. In this study, we present a method for fabricating top-gate graphene field-effect transistors (FETs) by incorporating a metal interlayer between the dielectric and graphene. The deposition of an ultrathin Ti layer facilitates the formation of a uniform HfO₂ layer on the graphene surface via atomic layer deposition (ALD). During the ALD process, the Ti layer oxidizes to TiO₂, which has a negligible impact on the current flow along the graphene channel. The mobility of graphene in the FET was enhanced in relation to the SiO₂-based back-gate FET by modifying the thin HfO₂ top-gate dielectric deposited on the Ti interlayer. Furthermore, shifts in the Dirac point and subthreshold swing were markedly reduced owing to the reduction in charge scattering caused by the presence of trap sites at the interface between graphene and SiO₂. This route to modulating the interface between 2D material-based heterostructures will provide an opportunity to improve the performance and stability of 2D electronics and optoelectronics.

The composite of CVD-grown Gr is a promising method for improving the electrical properties of Cu-based microscale materials. Almost all of the previous works focused on the CVD-grown continuous Gr. However, after the combination with surface of Cu substrate, the continuous Gr is prone to fracture or peeling when it is bent under strain in practical applications with low bending stability, leading to a decrease in its conductivity. In this study, significantly enhanced electrical properties and bending stability are demonstrated by synthesizing CVD-grown Gr sheets layers on microscale-diameter Cu wires, including 10.9% higher electrical conductivity and 7.9% higher maximum current density compared to commercial pristine Cu wires. After the test of bending cycles, Gr sheets/Cu wires exhibit extraordinary bending stability, with less than 1.3% conductivity changes for wires. In contrast, the continuous Gr/Cu wires show poor bending stability with a nearly 10% reduction in conductivity. Hence, the Gr sheets/Cu wires have significant advantages in practical applications.

Electrochemical exfoliation of graphite to produce graphene flakes is receiving increased attention worldwide due to the simplicity and efficiency of the method. This study examines the effects of different exfoliation mediums, such as nitric acid, sulfuric acid, hydrochloric acid, and potassium hydroxide, on the characteristics of electrochemically exfoliated graphene flakes (EEGFs) and their performance in supercapacitor applications. The study demonstrates that the choice of exfoliation medium significantly impacts the electrochemical characteristics and energy storage capabilities of the resultant graphene flakes. Graphene exfoliated in hydrochloric acid exhibits superior performance, which is attributed to an optimal balance of high conductivity, low defect density, and accessible surface area. Nitric acid-exfoliated graphene, despite being defect rich, offers competitive performance due to increased active sites and enhanced ion accessibility. In contrast, graphene flakes exfoliated in potassium hydroxide present the lowest electrochemical performance and the highest defect density. These findings provide valuable insights into tailoring the properties of electrochemically exfoliated graphene for high-performance energy storage devices.

Bisphenol F (BPF) is a substitute agent for bisphenol A and is widely used in the production of materials such as epoxy resins and plastics. BPF accumulates in surface water because of its nonbiodegradable and recalcitrant nature, making it difficult to remove. In this study, the removal of BPF through a photocatalytic process was evaluated using zinc oxide (ZnO)/reduced graphene oxide (RGO) microspheres. A spray drying method was used to prepare the ZnO/RGO microspheres, which combine the photocatalytic efficiency of ZnO with the high electron mobility and large surface area of RGO, achieving a bandgap of 2.53 eV. Structural and morphological analyses confirmed the successful hybridization of the ZnO/RGO microsphere composite. The photocatalytic activity of the ZnO/RGO microspheres was evaluated under various light sources, with the highest degradation efficiency achieved under ultraviolet C irradiation. The optimal catalyst dosage of the ZnO/RGO microspheres was determined to be 0.1 g/L for BPF removal (BPF initial concentration = 5 mg/L). Scavenger tests revealed the dominance of superoxide radicals ( O2 ·−) in the degradation process. The effects of pH (3.52–9.59), ions ( Cl−, NO3 −, and SO4 2−), and natural organic matter were also examined to assess the practical applicability of the ZnO/RGO microsphere photocatalytic system. High pH levels and the presence of NO3 − (> 10 mM) were found to enhance BPF removal. This research highlights the potential of the ZnO/RGO microspheres as efficient photocatalysts for the removal of BPF in aqueous solutions.

하수 및 폐수 환경에서의 콘크리트 구조물은 부식성이 강한 황산 환경에 노출되어 석고와 에트링가이트 형성을 통해 심각한 열화를 초래한다. 본 연구는 이를 해결하기 위해 그래핀 나노플레이트릿(GNP)이 시멘트 모르타르의 내산성 향상에 미치는 효과에 대 해 연구하였다. GNP는 시멘트 중량 기준으로 0.05 wt.%, 0.10 wt.%, 0.15 wt.%로 혼합하였으며, 시편은 28일간의 수중양생 후 0.05 M 황산에 30일 동안 노출시켰다. 내구성 성능은 수분 흡수율, 질량 손실률, 잔류 압축강도 시험을 통해 평가했다. 그 결과, 0.10 wt% GNP는 수분 흡수율을 감소시키고, 질량 손실을 제한하며, 98.9%의 압축강도를 유지함으로써 내산성을 크게 향상시켰다. GNP 함량이 0.15 wt% 이상으로 증가하면 응집이 발생하여 열화가 심화되었다. 이 연구는 GNP를 최적 농도인 0.10 중량%로 첨가하면 황산에 대한 내구성이 향상되고 가혹 환경에서의 장기 인프라 개발 분야에 유망한 잠재력이 있다는 결론을 내렸다.