Graphene Oxide Nanoribbons Research Articles

Compositing LaSrMnO3 perovskite and graphene oxide nanoribbons for highly stable asymmetric electrochemical supercapacitors

The anticipated large contribution of renewable energy resources to the sector of energy production strongly motivated the development of energy storage technologies, of which supercapacitors have drawn a lot of attention. In this work, Lanthanum-Strontium-Manganese-oxide (LSMO) perovskite nanoparticles, graphene oxide nanoribbons (GONRs), and LSMO-GONRs composite were synthesized and tested as electrode materials for supercapacitor applications. The LSMO was synthesized using the co-precipitation/calcination method, while the GONRs were synthesized using the oxidative unzipping of multi-walled carbon nanotubes. The physical/chemical structures were studied using XRD, FT-IR, SEM, TEM, SAED, and XPS. In 1 M KOH, the LSMO-GONRs electrode exhibited a specific capacitance of 490F/g compared to 342F/g and 294F/g for GONRs and LSMO electrodes, respectively, at 1 A/g, showcasing a performance that is not just superior but truly impressive, to the different types of perovskite/carbon-based material composites. The fabricated asymmetric SC device of LSMO-GONRs//GONRs exhibited a potential window of 1.7 V, a specific capacitance of 92.3F/g, an energy density of 38 Wh/kg, and a power density of 860 W/kg at 1 A/g. Moreover, the LSMO-GONRs//GONRs device showed excellent capacity retention and Coulombic efficiency after 10,000 cycles at 10 A/g, revealing the promising employment of LSMO-GONRs composite as a highly stable material for supercapacitor applications.

Joule and photothermal heating techniques for oil desorption with techno-economic feasibility and environmental impact analysis

Joule and photothermal heating offer promising avenues for enhancing oil recovery, desorption, and reusability by reducing the viscosity of highly viscous oils, thereby facilitating their mobility on sorbent surface. This study developed a heatable reduced graphene oxide nanoribbon (r-GONR)-coated polyvinylidene fluoride (PVDF) oil sorbent to address these viscosity challenges. The application of heating increased oil desorption by approximately 50%, significantly outperforming the conventional PVDF mat. The r-GONR sorbent, leveraging the photothermal effect, demonstrated exceptional reusability, maintaining 40% oil desorption efficiency up to the 10th cycle. Furthermore, its high oil desorption and reusability translated into considerable economic benefits, with a revenue potential of 6.4–29.0 $/m2, alongside significant environmental impact reduction. This study introduces a novel, sustainable approach to oil desorption and reuse, underscoring the practical applications of heatable materials in enhancing oil recovery.

Extraction and detection of sulfonamide antibiotics in milk using magnetic solid-phase adsorbent based on molecular mechanics and DFT calculations

Based on the foundation of calculations in molecular mechanics and density functional theory (DFT) for in-depth mechanistic studies, this paper proposes the sample multi-residue analysis method of five common sulfonamide antibiotics (SAs) in milk. Fe3O4 nanoparticles modified magnetic graphene oxide nanoribbons (Mag-GONRs) with superior dispersibility and dispersion stability, were developed and firstly utilized to rapidly extract residual SAs from milk. Therefore, various SAs in complex samples could be simultaneously determined solely by high performance liquid chromatography-ultraviolet detector (HPLC-UV) without the need for complicated pretreatment processes. In order to obtain satisfactory extraction efficiency, indispensable investigation and optimization were conducted on some parameters influencing the extraction efficiency. And the extracted SAs were determined by. Good linearity for all analytes was achieved with appropriate correlation coefficients (R2 higher than 0.9978). The limits of detection ranged from 0.060 to 0.075 ng·mL−1. Recoveries of the sulfonamides in spiked milk samples were between 79.6 % and 114.6 %, with relative standard deviations within 12 %. Interestingly, with the assistant of computational chemistry, the efficient extraction of Mag-GONRs onto SAs has been validated at the molecular and quantum levels, further elucidating the adsorption mechanism based on non-covalent interactions. In the context of theoretical research and experimental results mutually supporting each other, a practical detection method with actual application value has been proposed in monitoring the residual sulfonamides in milk by the common devices.

Synergistic anti-corrosion and anti-wear of epoxy coating functionalized with inhibitor-loaded graphene oxide nanoribbons

The synergy between corrosion protection and wear resistance is an effective strategy for the development of multifunctional coating to withstand complex working conditions. This study reports an epoxy resin coating filled with benzotriazole loaded metal-organic frameworks (BTA-MOFs) functionalized graphene oxide nanoribbons (GONR) that exhibit active anti-corrosion, act as a barrier to corrosive ion, and enhance wear resistance. The GONR@BTA-MOFs composite is synthesized through chemically etching multi-walled carbon nanotubes and subsequent electrostatic self-assembly corrosion inhibitors loaded MOFs onto the GONR. The composite demonstrates improved compatibility with epoxy resins compared to carbon nanotubes. The anti-corrosion performance of the composite coating is investigated using electrochemical impedance spectroscopy. After immersing in a 3.5 wt.% NaCl solution for 25 d, the alternating current impedance of the composite coating is three orders of magnitude higher than that of pure epoxy resin. Simultaneously, the controlled release of the corrosion inhibitor retards the deterioration of the coating after localized damage occurrence, which functions as active corrosion protection. The GONR@BTA-MOFs/EP composite coating exhibits the highest corrosion potential of -0.188 V and the lowest corrosion current of 3.162 × 10−9 A cm−2) in the Tafel test. Tribological studies reveal a reduction in the friction coefficient from 0.62 to 0.08 after incorporating GONR@BTA-MOFs in the coating, with the wear volume being seven times lower than that of pure epoxy resin. The excellent lubrication effect of the nanomaterials reduces the coefficient of friction of the coating, thereby improving the abrasion resistance of the coating. The synergy between the self-lubrication of the two-dimensional layered fillers and the corrosion resistance of the smart inhibitor containers suggests a promising strategy for enhancing the performance of epoxy resins under complex working conditions.

Green Preparation of S, N Co-Doped Low-Dimensional C Nanoribbon/C Dot Composites and Their Optoelectronic Response Properties in the Visible and NIR Regions.

The green production of nanocomposites holds great potential for the development of new materials. Graphene is an important class of carbon-based materials. Despite its high carrier mobility, it has low light absorption and is a zero-bandgap material. In order to tune the bandgap and improve the light absorption, S, N co-doped low-dimensional C/C nanocomposites with polymer and graphene oxide nanoribbons (the graphene oxide nanoribbons were prepared by open zipping of carbon nanotubes in a previous study) were synthesized by one-pot carbonization through dimensional-interface and phase-interface tailoring of nanocomposites in this paper. The resulting C/C nanocomposites were coated on untreated A4 printing paper and the optoelectronic properties were investigated. The results showed that the S, N co-doped C/C nanoribbon/carbon dot hybrid exhibited enhanced photocurrent signals of the typical 650, 808, 980, and 1064 nm light sources and rapid interfacial charge transfer compared to the N-doped counterpart. These results can be attributed to the introduction of lone electron pairs of S, N elements, resulting in more transition energy and the defect passivation of carbon materials. In addition, the nanocomposite also exhibited some electrical switching response to the applied strain. The photophysical and doping mechanisms are discussed. This study provides a facile and green chemical approach to prepare hybrid materials with external stimuli response and multifunctionality. It provides some valuable information for the design of C/C functional nanocomposites through dimensional-interface and phase-interface tailoring and the interdisciplinary applications.

Graphene oxide nanoribbons conjugated with 1, 2-distearoyl-sn-glycero-3 phosphoethanolamine-poly (ethylene glycol)-transferrin enhanced targeted delivery and cytotoxicity of raloxifene against breast cancer

The clinical utility of raloxifene (RLX), a selective estrogen receptor modulator (SERM), has been compromised by severe side effects and unfavorable drug properties. To address these, a transferrin (Tf) conjugated graphene oxide nanoribbon (GONR) platform was tried for RLX. The stability of GONRs in biological media was improved by surface modification with 1, 2-Distearoyl-sn-glycero-3 phosphoethanolamine-Poly (ethylene glycol) (DSPE-PEG). The Tf molecule was covalently attached to DSPE-PEG (DPT) using EDC-NHS chemistry. The surface of GONR was then modified with DSPE-PEG (DP) or DPT and loaded with RLX (GDP-RLX and GDPT-RLX). The final formulations were characterized for drug loading and stability. The anticancer activities of pure RLX, GDP-RLX, and GDPT-RLX were evaluated and compared in all the in vitro and in vivo studies. In vitro cell line studies showed that GDPT-RLX have significantly high cytotoxicity, cellular uptake, apoptosis induction, G2/M phase arrest, anti-migration properties, and apoptotic protein expression, followed by GDP-RLX and RLX. Pharmacokinetics and tumor biodistribution were also found to be excellent with GDPT-RLX. The in vivo tumor therapy and tumor evaluation outcomes were also consistent with the in vitro data. The Tf conjugated GDPT-RLX represents a promising approach for targeted and sustained delivery of RLX with enhanced therapeutic efficacy.

Particle size effect on graphene nanoribbons with iron oxide nanoparticles

The particle size effect on nanocomposites made of reduced graphene nanoribbons (GNRs) and iron oxide nanoparticles (IONPs) is studied. Three nanocomposites with different particle size were prepared by chemical reduction of IONPs formed by the co-precipitation method on graphene oxide nanoribbons. Several experimental techniques such as transmission electron microscopy, selected area electron diffraction and X-ray diffraction determined the particle size distribution and crystalline phases present in the samples. The specific surface area (SSA) of the nanocomposites was measured and discussed with the mean size of the IONPs. Depending on the mean size and surface distribution of the IONPs, samples with high SSA can be achieved. Magnetic measurements indicated that the particle size affects the magnetic properties of the nanocomposites. These results were discussed considering the effect of particle size, defects, amount of particles and interaction between the IONPs and GNRs surface. The potential application of the samples as supercapacitors was evaluated by calculating their specific capacitance from cyclic voltammetry measurements. The results showed that the specific capacitance increases with the SSA. This work confirms that the size of the IONPs significantly affects the properties of the nanocomposites, specifically the SSA, which is of great interest for various applications.

Effect of Functionalized Carbon Nanotubes and Graphene Oxide Nanoribbons on the Supercapacitive Behavior of Zr-Based Metal-Organic Frameworks in Acid Media

Metal-organic frameworks (MOFs) as a kind of crystalline porous materials have attracted much attention due to their high surface area and high electrochemical performance as electrode materials in supercapacitors 1. Recently, there has been a lot of interest in functionalized multiwalled carbon nanotubes (F-MWCNTs) based materials and especially graphene oxide nanoribbons (GONRs), which have unusual characteristics of ultrathin two-dimensional structures and, as promising materials for supercapacitors and other electrochemical energy storage devices. The F-MWCNTs and GONRs' high electrical conductivity, highly changeable surface area, strong chemical stability, excellent mechanical behavior, and capacity to modify attributes for the desired application are behind the reasons for choosing to make a composite of these materials with Zr-MOF 2.In this work, Zr-MOF was synthesized using the solvothermal method 3, MWCNTs were functionalized using acid washing (3 M H2SO4: 1 M HNO3), and GONRs were fabricated using the oxidative unzipping method 4. The Zr-MOF/F-MWCNTs and Zr-MOF/GONRs composites were prepared through physical mixing. The physical and chemical structures of the synthesized Zr-MOF, F-MWCNTs, and GONRs were evaluated using XRD, SEM, TEM, FT-IR, Raman spectroscopy, and XPS. The supercapactive behavior of the prepared composites was evaluated in comparison to their components (Zr-MOF, F-MWCNTs, and GONRs) in 1M H2SO4 utilizing various evaluation systems (three and two-electrode systems). Zr-MOFs showed a high specific capacitance (248 F/g at 1 A/g), making it a promising supercapacitor electrode material. That performance is dramatically improved by the addition of the nanocarbon materials (F-MWCNTs and GONRs). Zr-MOF-GONRs showed the highest specific capacitance (448 F/g at 1 A/g), with a large potential window (1.7 V) in the three-electrode system extended to (2V) in the two-electrode system, and good stability over 10,000 cycles at a high current density of 10 A/g. Reference: (1) Tan, Y.; Zhang, W.; Gao, Y.; Wu, J.; Tang, B. Facile Synthesis and Supercapacitive Properties of Zr-Metal Organic Frameworks (UiO-66). RSC Adv. 2015, 5 (23), 17601–17605. https://doi.org/10.1039/c4ra11896k.(2) Shrivastav, V.; Sundriyal, S.; Tiwari, U. K.; Kim, K. H.; Deep, A. Metal-Organic Framework Derived Zirconium Oxide/Carbon Composite as an Improved Supercapacitor Electrode. Energy 2021, 235, 121351. https://doi.org/10.1016/j.energy.2021.121351.(3) Abdelhamid, H. N. UiO-66 as a Catalyst for Hydrogen Production: Via the Hydrolysis of Sodium Borohydride. Dalton Trans. 2020, 49 (31), 10851–10857. https://doi.org/10.1039/d0dt01688h.(4) Kosynkin, D. V.; Higginbotham, A. L.; Sinitskii, A.; Lomeda, J. R.; Dimiev, A.; Price, B. K.; Tour, J. M. Longitudinal Unzipping of Carbon Nanotubes to Form Graphene Nanoribbons. Nature 2009, 458 (7240), 872–876. https://doi.org/10.1038/nature07872.

(Nanocarbons Division Poster Award, 3rd Place) Hybrid Supercapacitance and Stability of Fe-Based Metal-Organic Frameworks/Graphene Oxide Nanoribbons Composite Allover the pH Range

Adopting renewable energy sources is growing fast, and hence it should be accompanied by tremendous efforts to develop energy storage technologies that can mitigate the intermittent nature of these sources. Supercapacitors (SCs) are considered among the most promising technologies for that purpose due to their high durability, power density, and charging/discharging competency. SCs have two types according to their electrochemical charge storage mechanism: pseudocapacitance (PCs) or battery-like behavior and electrochemical double-layer capacitors (EDLCs). The development of next-generation supercapacitors requires a holistic approach that integrates both mechanisms. Because of their huge surface area, porous structure, and abundance of active redox sites, metal-organic frameworks (MOFs) have exceptional potential in energy storage devices. However, due to the MOFs’ low conductivity and stability, they are in need to be mixed with highly conductive and stable materials such as carbon-based ones.In this work, Fe-based MOFs were selected to be responsible for mainly the battery-like contribution to the overall supercapacitance due to the presence of the redox-active sites. Even though little attention has been given to the Fe-based MOFs they showed a promising performance in several solutions, with low stability.1,2 To enhance the Fe-MOFs stability and conductivity and add an EDLC component to the overall capacitance behavior graphene oxide nanoribbon (GONRs) was used. The GONRs' exceptional properties such as ultrathin two-dimensional structures, superior mechanical behavior, strong chemical stability, and high electrical conductivity make them promising materials for supercapacitor applications.In this study, Fe-MOFs were synthesized using a hydrothermal method,3 and GONRs were prepared using an oxidative unzipping method.4 A composite of Fe-MOFs/GONRs was prepared by physical mixing. The physical and chemical properties of the synthesized Fe-MOFs, GONRs, and Fe-MOFs/GONRs were characterized using XRD, SEM, TEM, FT-IR, Raman spectroscopy, and XPS. Since the electrolyte properties have a substantial impact on the supercapacitive behavior and stability of the electrode materials, the specific capacitance of the prepared composites was measured in 1M H2SO4, 1M KOH, 1M K2SO4, and 1M KCl utilizing different evaluation systems (three and two-electrode systems). The Fe-MOFs/GONRs composite showed a significant synergistic effect in comparison to its pure components. Further discussion will be given regarding the pH and ion size/type effect on the supercapacitive performance and stability.

Graphene nanoribbon hydrogel scaffold for highly conductive and robust polyimide nanocomposite

Although highly loaded graphitic nanocarbon materials effectively enhance the electrical, mechanical, and thermal properties of polymeric materials, their practical implementation has been hindered by severe aggregation issues. Here, we propose a method to achieve homogeneous nanocarbon-polyimide (PI) composites by integrating graphene oxide nanoribbons (GONRs) with polyamic acid ammonium (PAA) salt, a precursor of PI. Self-assembled scaffold structure of GONRs hydrogel enables the uniform integration and immobilization of PAA within the GONR scaffold, mitigating aggregation concerns. The resulting GONR/PAA hydrogel, formed through physical interactions, can be coated onto substrates via a shear stress-induced bar coating method due to its viscoelastic rheological properties. Subsequent heat treatment at 400 °C triggers the imidization reaction of PAA and the reduction of GONR, facilitating the formation of uniformly integrated GNR/PI nanocomposite coatings. Under optimized conditions, incorporating a high-loading GONR content in PAA (95 wt% of GONR and 5 wt% of PAA) yielded GNR/PI composites with excellent mechanical properties, exhibiting a hardness of 0.75 GPa and an elastic modulus of 8.3 GPa. Additionally, this GNR/PI composite displayed a good electrical conductivity of 3890 S/m, attributed to the electrical pathways formed by GNRs within the PI matrix.

Neural Tissue-Like, not Supraphysiological, Electrical Conductivity Stimulates Neuronal Lineage Specification through Calcium Signaling and Epigenetic Modification.

Electrical conductivity is a pivotal biophysical factor for neural interfaces, though optimal values remain controversial due to challenges isolating this cue. To address this issue, conductive substrates made of carbon nanotubes and graphene oxide nanoribbons, exhibiting a spectrum of conductivities from 0.02 to 3.2Sm-1, while controlling other surface properties is designed. The focus is to ascertain whether varying conductivity in isolation has any discernable impact on neural lineage specification. Remarkably, neural-tissue-like low conductivity (0.02-0.1Sm-1) prompted neural stem/progenitor cells to exhibit a greater propensity toward neuronal lineage specification (neurons and oligodendrocytes, not astrocytes) compared to high supraphysiological conductivity (3.2Sm-1). High conductivity instigated the apoptotic process, characterized by increased apoptotic fraction and decreased neurogenic morphological features, primarily due to calcium overload. Conversely, cells exposed to physiological conductivity displayed epigenetic changes, specifically increased chromatin openness with H3acetylation (H3ac) and neurogenic-transcription-factor activation, along with a more balanced intracellular calcium response. The pharmacological inhibition of H3ac further supported the idea that such epigenetic changes might play a key role in driving neuronal specification in response to neural-tissue-like, not supraphysiological, conductive cues. These findings underscore the necessity of optimal conductivity when designing neural interfaces and scaffolds to stimulate neuronal differentiation and facilitate the repair process.

High-Efficiency Adsorption of Uranium from Wastewater Using Graphene Oxide/Graphene Oxide Nanoribbons/Chitosan Nanocomposite Aerogels.

A chemical exfoliation and freeze-drying technique was used to create graphene oxide/graphene oxide nanoribbons/chitosan aerogels (GO/GONRs/CS). Aerogels were utilized to study uranium adsorption through batch experiments. Environmental influences on U(VI) adsorption were studied, including the starting concentration of U(VI), contact time, pH, and temperature. In order to characterize the composite, FTIR, SEM, XRD, and TEM analyses were used. A pseudo-second-order kinetic model may adequately represent the kinetics of U(VI) adsorption onto the surface of aerogels. The Freundlich model can explain the adsorption isotherm; the maximal adsorption capacity for U(VI) was determined to be 1208.85 mg/g; the adsorption process for U(VI) was endothermic, spontaneous, and pH-dependent; and the mechanism of adsorption is the chemisorption process. Chemisorption typically involves strong chemical interactions between the adsorbate (uranium ions) and the functional groups present on the surface of the adsorbent (the aerogel). Graphene oxide and graphene oxide nanoribbons contain oxygen-containing functional groups such as carboxyl (-COOH), hydroxyl (-OH), and epoxy (-O-) groups, which can act as active sites for chemical bonding. Chitosan, a polysaccharide derived from chitin, also possesses functional groups like amino (-NH2) and hydroxyl groups. Uranium ions, in their U(VI) form, can form chemical bonds with these functional groups through various mechanisms such as electrostatic interactions, complexation, and coordination bonds. The combination of graphene oxide-based materials and chitosan in the nanocomposite aerogel offers several advantages, including a large specific surface area, chemical stability, and the presence of functional groups for effective uranium adsorption.

Nickel-Induced Reduced Graphene Oxide Nanoribbon Formation on Highly Ordered Pyrolytic Graphite for Electronic and Magnetic Applications.

The development of nanoribbon-like structures is an effective strategy to harness the potential benefits of graphenic materials due to their excellent electrical properties, advantageous edge sites, rapid electron transport, and large specific area. Herein, parallel and connected magnetic nanostructured nanoribbons are obtained through the synthesis of reduced graphene oxide (rGO) using NiCl2 as a precursor with potential applications in nascent electronic and magnetic devices. Several analytical techniques have been used for the thorough characterization of the modified surfaces. Atomic force microscopy (AFM) shows the characteristic topographical features of the nanoribbons. While X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Raman spectroscopy provided information on the chemical state of Ni and graphene-like structures, magnetic force microscopy (MFM) and scanning Kelvin probe microscopy (SKPFM) confirmed the preferential concentration of Ni onto rGO nanoribbons. These results indicate that the synthesized material shows 1D ordering of nickel nanoparticles (NiNPs)-decorating tiny rGO flakes into thin threads and the subsequent 2D arrangement of the latter into parallel ribbons following the topography of the HOPG basal plane.

Nitrogen‐Doped Graphene Oxide Nanoribbon Supported Cobalt Oxide Nanoparticles as High‐Performance Bifunctional Catalysts for Zinc–Air Battery

Developing high‐performance, high‐stability, and low‐cost nonprecious metal catalysts to enhance the performance of zinc–air batteries (ZABs) holds significant importance. A bifunctional catalyst consisting of cobalt oxide (CoO) nanocrystals on nitrogen‐doped reduced graphene oxide nanoribbons (N‐rGONR) as a novel substrate is successfully synthesized in this work. This synthesized bifunctional catalyst exhibits mesoporous structure, and remarkable synergistic effects between CoO nanocrystals and N‐rGONR, demonstrating excellent activity and durability in both oxygen reduction reactions and oxygen evolution reactions. Notably, the resulting aqueous electrolyte ZABs show a high discharge peak power density of 196 mW cm−2, a high specific capacity of 615.9 mAh g−1, and long‐time stability for 648 h. Furthermore, the assembly of 1D and 2D flexible solid‐state ZABs fabricated using this bifunctional catalyst exhibits stable electrochemical performance, even under severe deformation. These results underscore the considerable promise of implementing the CoO@N‐rGONR catalyst structure in next‐generation advanced energy storage and conversion devices.

High surface area microporous carbon nanocubes from controlled processing of graphene oxide nanoribbons

A new, facile, and template-free method to prepare high surface area microporous carbon nanocubes (CNCs) from a mixture of graphene oxide nanoribbons (NRs), graphene oxide, and carbon dots is reported. The nanoribbons, approximately 30 nm wide and with lengths ranging from a few tens of nanometres up to several micrometres, were obtained from the oxidation of Black Pearls 2000 carbon black in nitric acid solution. The non-purified nanoribbons further contained additional fragments of graphene oxide, and of graphene oxide quantum dots. Slow pyrolysis of the nanoribbon mixture with slow heating rates, e.g., 3 °C/min, yielded carbon nanocubes approximately 250 nm in size with surface areas greater than 900 m2/g. Heating rates of 50 °C/min led to carbons with ∼800 m2/g surface area but bulk morphology. Precipitating the nanoribbons in potassium hydroxide solution, followed by carbonization, yielded microporous nanoparticle aggregates that were 20 nm in size with surface areas greater than 2000 m2/g. The particles exhibited complex, quasi-spherical morphology. Pyrolysis of other products obtained from oxidation in HNO3 of different grades of carbon black, specifically graphene oxide nanoparticles and quantum dots, yielded high surface area microporous carbons but with bulk morphology regardless of the processing conditions. Despite the lower surface area and pore volume of the CNCs in comparison to the nanospheres, the former contained ultramicropores that were highly accessible to CO2 as a molecular probe and had excellent selectivity of CO2 over N2. Hence, CNC materials have promising properties for applications where particle surface-to-volume ratios, high internal surface areas, and abundant super and ultramicropores are desired.

Dry‐Wet Hybrid Direct Printing of Laser‐Induced Graphene and Zinc Oxide Nanoribbons for Continuous‐Flow Manufacturing of Flexible Wearable Photodetectors

AbstractFlexible wearable electronics enable an in situ and real‐time measurement of human physiology and micro‐environment. Although large‐scale production of flexible wearable electronics is demonstrated using direct printing techniques, the “wet” nature of these techniques requires multiple procedures and chemicals to prepare printable inks, increasing the complexity and cost. Here, a dry‐wet hybrid direct printing is developed for the mass production of flexible wearable photodetectors, in which a “dry” direct laser writing and a “wet” screen printing are employed to fabricate laser‐induced graphene as electrode layer and zinc oxide as photosensitive layer, respectively. The liquid‐free fabrication of LIG significantly reduces the complexity and cost of the production. An automatic conveyor belt is designed to realize continuous‐flow manufacturing. The photodetectors demonstrate good ultraviolet (UV) photodetection performances, such as a photo‐to‐dark current ratio (Iphoto/Idark) of 5.67 × 105, approaching the record of similar devices. The manufacturing system presents a high reproducibility, considering that Iphoto/Idark only fluctuates within 7.10%. The flexible photodetectors are worn as wristbands after being integrated with a data acquisition and transmission circuit. UV intensity is real‐time monitored on a self‐developed mobile application. The continuous‐flow manufacturing based on the developed dry‐wet hybrid direct printing sheds light on the mass production of flexible wearable electronics.

A novel non-enzymatic electrochemical glucose sensors based on graphene oxide nanoribbons: Tracking energy expenditure and nutritional intake in sports

This work revealed the development of a novel non-enzymatic electrochemical sensor for glucose detection based on a modified glassy carbon electrode made of graphene oxide nanoribbons (GONRs). The TEM, XRD), XPS, FTIR, and Raman spectroscopy were used to characterize the shape and structure of the modified electrode made of GONRs. Using amperometry and cyclic voltammetry (CV), the nanocomposite's electrochemical performance was assessed (AMP). The TEM results support the XPS, Raman, and XRD observations, demonstrating the capability of the suggested approach to generate single-layered GONRs with good edge linearity. The suggested non-enzymatic glucose sensing method was found to be selective, stable, repeatable, and reproducible through electrochemical analyses. The response behavior of GONRs/GCE was found to be linear within the 0.1–105 mM range, and the sensitivity and detection limit were found to be roughly 20.815 µA/mM and 3 µM, respectively. To verify the GONRs/GCE sensor's practicality and viability, tests were conducted on human serum and orange juice samples. The recovery rate ranged from 94.00% to 99.20%, according to the results, and the relative-standard deviation (RSD) values were 3.21% to 4.41%. These encouraging RSD and recovery rates showed that GONRs/GCE would work well as electrodes for measuring glucose in actual samples.

Extremely efficient aerogels of graphene oxide/graphene oxide nanoribbons/sodium alginate for uranium removal from wastewater solution

Waste-water pollution by radioactive elements such as uranium has emerged as a major issue that might seriously harm human health. Graphene oxide, graphene oxide nanoribbons, and sodium alginate nanocomposite aerogels (GO/GONRs/SA) were combined to create a novel nanocomposite using a modified Hummer's process and freeze-drying as an efficient adsorbent. Batch studies were conducted to determine the adsorption of uranium (VI) by aerogel. Aerogels composed of (GO/GONRs/SA) were used as an effective adsorbent for the removal of U (VI) from aqueous solution. Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to describe the structure, morphologies, and characteristics of (GO/GONRs/SA) aerogels. The initial concentration of uranium (VI) and other environmental factors on U (VI) adsorption were investigated, period of contact, pH, and temperature. A pseudo-second-order kinetic model can be employed to characterize the kinetics of U (VI) adsorption onto aerogels. The Langmuir model could be applied to understand the adsorption isotherm, and the maximum adsorption capacity was 929.16 mg/g. The adsorption reaction is endothermic and occurs spontaneously.

Biocompatibility assessment of chemically modified GONRs with hemoglobin and histopathological studies for its toxicity evaluation.

Transition metal-Schiff base complexes are found to be important for biomedical applications but have demerits of being homogeneous complexes, thus their synthesis on the surface of graphene oxide nanoribbons (GONRs), materials of specific interest, can be beneficial for preparing advanced graphene-based materials for biomedical applications. Of foremost importance is their safety and biocompatibility with biological systems. In this study, a transition metal-Schiff base complex has been synthesized on the surface of a GONR (Ni-S-GNR) using 3-aminopropyltriethoxysilane and pyridine-2-carbaldehyde and complexing nickel. This Ni-S-GNR was characterized well by various physicochemical techniques. The evaluation of biocompatibility of Ni-S-GNR with hemoglobin confirmed binding interactions and influence on the native structure of hemoglobin. It was found that there was alteration in the secondary and tertiary structures of hemoglobin. In addition, histopathological studies on the liver and kidney cells of rats revealed non-toxicity of Ni-S-GNR towards these cells. Overall, Ni-S-GNR was found to be compatible with protein as the native structure was not destroyed and was non-toxic to cells.

Introduction of 1D rGO nanoribbons as spacers between 2D MXenes for a high-performance electrode for supercapacitors.

Two-dimensional (2D) transition-metal carbide Ti3C2TX (MXene) possesses good electrical conductivity, high specific surface areas and metal oxide-like surfaces, which make it ideal for application in supercapacitors with both high energy density and power density. However, similar to other 2D materials, the issue of self-stacking leads to narrower ion-transport channels, along with a drastic reduction in active sites, thus severely limiting the performance of MXene-based electrodes. To address this problem, this work proposes to introduce one-dimensional (1D) reduced graphene oxide (rGO) nanoribbons as spacers between MXene nanosheets to construct a composite structure for inhibiting self-stacking. As expected, owing to the steric effect and high aspect ratio of rGO nanoribbons, the fabricated MXene/rGO hybrid electrode, with the addition of 5 wt% graphene oxide (GO), exhibits a greatly improved specific capacitance (397.4 F g-1 at 5 mV s-1) and an unparalleled rate capability (with a capacitance retention of 52.9% at 2000 mV s-1). This work sheds significant light on the development of MXene-based materials for advanced energy storage devices.