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.

In this paper, poly(glycolic acid–co-DL–lactic acid) (PGDLLA)/poly(ɛ-caprolactone) (PCL) incompatible nanocomposites were combined with multiscale modeling (MSM) in a ratio of 80/20. Since the behavior and mechanical properties of blends depend significantly on the interphase region, the compatibilizer poly(l,l-lactic acid–co-ɛ-caprolactone) (P(lLA-co-ɛ-CL)) was used to improve compatibility and graphene oxide (GO) was used to increase the interphase strength of PGDLLA matrix/PCL. This work was done by mixing solvent to achieve the optimum disperse of GO in the matrix. The investigation of interfacial phenomenon by the theoretical interfacial models is important. Under the assumption of constant modulus and elastic deformation in the zero interface region, the predictions in this region are more unreliable when the calculations of experimental mechanical properties are analyzed in detail. In this study, PGDLLA/P(lLA-co-ɛ-CL)/PCL compounds were compared with the MSM approach to predict the plastic deformation in the stress–strain behavior. In contrast to the hypothesis that a simple look at the interphase area in nanocomposites, a finite element code is proposed to evaluate the efficiency of the interphase area. Both experimental results and FEM analysis showed that Young’s modulus increases by incorporating GO into GO/PGDLLA/P(lLA-co-ɛ-CL)/PCL nanocomposites; the amount of increase for incorporating 1 phr GO is about 61%.

The accurate detection of vital biomarkers such as Ascorbic Acid (AA), Uric Acid (UA) and Nitrite ( NO2 −) is crucial for human health surveillance. However, existing methods often struggle with concurrent detection and quantification of multiple species, highlighting the need for a more effective solution. To address this challenge, this study aimed to develop a multifunctional electrochemical sensor capable of parallel detection of AA, UA and NO2 − using a synergistic combination of Graphene Oxide (GO) and Cadmium Sulfide (CdS) materials. Notably, the fabricated CdS@GO/Glassy Carbon Electrode (GCE) exhibited exceptional electrochemical activity, as evidenced by Differential Pulse Voltammetry (DPV) analysis. The sensor demonstrated remarkable sensitivity (8.13, 10.12, and 9.05 μA·μM−1·cm−2) and ultra-low detection limits (0.034, 0.062, and 0.084 μM) for AA, UA and NO2 −, respectively. Furthermore, it successfully identified single molecules of each analyte in aqueous and biologic fluid samples, with recovery values comparable to those obtained using High-Performance Liquid Chromatography (HPLC) standard addition methods. The significance of this study lies in developing a novel CdS@ GO/GCE sensor that enables concurrent detection and quantification of multiple vital biomarkers, offering a promising tool for human health monitoring and diagnosis.

Supercapacitors, renowned for their high power density and rapid charge-discharge rates, are limited by their low energy density. This limitation has prompted the need for advanced electrode materials. The present study investigated reduced graphene oxide (rGO) in two distinct structures, as a film and as an aerogel, for use as supercapacitor electrodes. The rGO film, prepared by vacuum filtration and thermal reduction, exhibited a compact, lamellar structure, while the aerogel, synthesized through hydrothermal treatment, was a highly porous three-dimensional network. Electrochemical analyses demonstrated the aerogel’s superior performance, as shown by a specific capacitance of 121.2 F/g at 5 mV/s, with 94% capacitance retention after 10,000 cycles. These findings emphasize the importance of structural design in optimizing ion accessibility and charge transfer. They also demonstrate the potential of rGO aerogels for increasing the energy storage efficiency of advanced supercapacitor systems.

As the pace of technological advances accelerates, the role of electrical energy storage has become increasingly important. Among various storage solutions, supercapacitors are garnering significant attention. Their unique attributes, including high power density, rapid charge/discharge capabilities, and extended lifecycle, position them as a promising alternative to conventional batteries. This study investigates the synthesis of a nickel oxide (NiO) and nickel oxide/graphene oxide (NiO/GO) composite using a single-step hydrothermal method, to evaluate their potential as supercapacitor electrode materials. The synthesized NiO, graphene oxide (GO), and NiO/GO composite were comprehensively characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy to analyze their crystal structures and chemical bonding. The XRD analysis confirmed the formation of an NiO phase with a rhombohedral crystal structure, and no change after GO incorporation. SEM analysis revealed the formation of spherical NiO particles and porous morphology of the NiO/GO composite, which also exhibited a spherical shape. The GO displayed a randomly arranged wrinkled sheet-like structure. Electrochemical analysis of the NiO/GO composite exhibited a remarkable specific capacitance of 893 F g-1 at a current density of 1 A g-1, surpassing that of NiO and GO alone, demonstrating NiO/GO has promising performance for supercapacitor applications. The charge transfer resistance, derived from the Nyquist plot, suggests that the reduction in charge transfer resistance contributed significantly to the improved capacitance. Additional stability studies of over 5,000 cycles at 5 A g-1 revealed an 85 % initial capacitance retention, confirming the advantages of GO inclusion to improve material retention for superior long-term performance. The asymmetric supercapacitor (ASC) assembled using an electrode with the configuration NiO/GO//activated carbon (AC) showed a specific capacitance of 77.8 F g-1 obtained at a current density of 0.5 A g-1.

본 연구에서는 산화 방지 특성이 있는 가려진 페놀기를 도입한 산화 그래핀(hindered phenol-grafted graphene oxide, HP-GO)을 합성한 후 탄화수소계 고분자인 sulfonated poly(arylene ether sulfone) (SPAES)을 기지체로 사용한 복합 막을 제조하여 고분자 연료전지 시스템에 응용하고자 하였다. HP-GO는 GO 표면의 하이드록시기(hydroxy group)와 HP의 염화 카 보닐(carbonyl chloride) 간의 친핵성 아실치환 반응을 통해 합성되었으며, HP-GO의 비율을 다르게 첨가한 복합 막을 제조한 후 선형 SPAES 막과의 비교를 통해 성능 특성 변화를 확인하였다. 특정 함량의 HP-GO를 첨가한 복합 막의 경우 선형 SPAES 막에 비해 체적 안정성과 기계적 강도 및 수소 이온 전도도가 증가된 것을 확인할 수 있었으며, 펜톤 평가(Fenton’s test) 진행 후 막 분해 시간 및 잔여 막 무게 비율이 증가되는 경향을 통해 화학적 내구성 역시 증가한 것을 확인할 수 있었다.