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Dual Function of Graphene Oxide for Assisted Exfoliation of Black Phosphorus and Electron Shuttle in Promoting Visible and Near-Infrared Photocatalytic H2 Evolution
摘要： The search for suitable photocatalysts with broadband absorption in visible and near-infrared (NIR) region is recognized as one of the most challenging issues on solar energy utilization. Black phosphorous (BP) is demonstrated as an effective visible and NIR activated material in solar energy conversion. However, traditional liquid exfoliation yield is low and the rigid structure and insoluble properties of pristine BP hinder its high-yield of hybridization. Herein, a new and stable noble-metal-free ternary photocatalyst molybdenum disulfide (MoS2)-BP/graphene oxide (GO) was constructed for splitting water to H2, showing dual functions of GO in synthetic and photocatalytic processes. Under visible-NIR light irradiation, the H2 evolution rates of MoS2-BP/GO was enhanced to 3.47 μmol h-1. Rapid electron injection efficiency from excited BP to GO and to MoS2 was confirmed by femtosecond transient absorption spectroscopy. This study provides new insight into the design of nanomaterials, and offers a noble-metal-free protocol with noble-metal-free.
关键词： visible and NIR,hydrogen evolution,graphene oxide,black phosphorous,noble-metal-free
更新于2025-11-19 16:51:07
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A Label-Free Fluorescent DNA Machine for Sensitive Cyclic Amplification Detection of ATP
摘要： In this study, a target recycled ampli?cation, background signal suppression, label-free ?uorescent, enzyme-free deoxyribonucleic acid (DNA) machine was developed for the detection of adenosine triphosphate (ATP) in human urine. ATP and DNA fuel strands (FS) were found to trigger the operation of the DNA machine and lead to the cyclic multiplexing of ATP and the release of single stranded (SS) DNA. Double-stranded DNA (dsDNA) was formed on graphene oxide (GO) from the combination of SS DNA and complementary strands (CS(cid:48)). These double strands then detached from the surface of the GO and in the process interacted with PicoGreen dye resulting in amplifying ?uorescence intensity. The results revealed that the detection range of the DNA machine is from 100 to 600 nM (R2 = 0.99108) with a limit of detection (LOD) of 127.9 pM. A DNA machine circuit and AND-NOT-AND-OR logic gates were successfully constructed, and the strategy was used to detect ATP in human urine. With the advantage of target recycling ampli?cation and GO suppressing background signal without ?uorescent label and enzyme, this developed strategy has great potential for sensitive detection of different proteins and small molecules.
关键词： cyclic ampli?cation,ATP detection,DNA machine,label-free ?uorescence,graphene oxide,logic gate
更新于2025-11-19 16:46:39
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Laser-induced synthesis and photocatalytic properties of hybrid organic–inorganic composite layers
摘要： A laser-based method was developed for the synthesis and simultaneous deposition of multicomponent hybrid thin layers consisting of nanoentities, graphene oxide (GO) platelets, transition metal oxide nanoparticles, urea, and graphitic carbon nitride (g-C3N4) for environmental applications. The photocatalytic properties of the layers were tested through the degradation of methyl orange organic dye probing molecule. It was further demonstrated that the synthesized hybrid compounds are suitable for the photodegradation of chloramphenicol, a widely used broad-spectrum antibiotic, active against Gram-positive and Gram-negative bacteria. However, released in aquatic media represents a serious environmental hazard, especially owing to the formation of antibiotic-resistant bacteria. The obtained results revealed that organic, urea molecules can become an alternative to noble metals co-catalysts, promoting the separation and transfer of photoinduced charge carriers in catalytic composite systems. Laser radiation induces the reduction of GO platelets and the formation of graphene-like material. During the same synthesis process, g-C3N4 was produced, by laser pyrolysis of urea molecules, without any additional heat treatment. The layers exhibit high photocatalytic activity, being a promising material for photodegradation of organic pollutants in wastewater.
关键词： transition metal oxide nanoparticles,urea,photocatalytic properties,hybrid organic–inorganic composite layers,graphene oxide,graphitic carbon nitride,methyl orange,laser-based synthesis,chloramphenicol
更新于2025-11-14 17:04:02
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The Preparation and Characterization of Fluorinated Graphene Oxide with Different Degrees of Oxidation
摘要： For many excellent graphene derivatives, tailoring the material properties is crucial to get a broader application. In the present work, a series of fluorinated graphene oxide (FGO) with various oxidation degree were synthesized using a modified Hummers method at different reaction temperatures. The structure and property of FGO were analyzed by X-ray diffraction (XRD), Fourier transform infra-red spectra (FT-IR), X-ray photoelectron spectra (XPS) and Zeta potential analysis. The results indicate that the oxygen contents range from 5.61 % to 21.96 % in FGO can be tuned by altering the reaction temperatures. The oxygen in FGO is presented mainly in the form of epoxide and carboxyl groups. With increasing reaction temperature from 50 °C to 90 °C, the oxygen content in FGO decreases and thicker multilayered FGO is formed with lower dispersibility.
关键词： Controllable oxidation,Fluorinated Graphene Oxide,Low temperature reaction
更新于2025-11-14 17:04:02
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Plasmonic MoO2 nanospheres assembled on graphene oxide for highly sensitive SERS detection of organic pollutants
摘要： The molybdenum oxide and graphene oxide (MoO2/GO) nanocomposite has been fabricated via simple hydrothermal assisted synthesis using Mo and MoO3 as precursors. The MoO2 nanospheres with porous hollow structure are assembled onto GO nanosheets. Profiting from the plasmonic effects of MoO2 and synergistic effect of MoO2 and GO, this hybrid nanomaterial exhibits significantly enhanced surface enhanced Raman scattering (SERS) activity for organic pollutants. The detection limit for rhodamine 6G (R6G) is 1.0 × 10?9 M, and the maximum enhancement factor (EF) reaches up to 1.05 × 107, which is the best among the semiconductor-based SERS materials. For practical application, the MoO2/GO SERS substrates are also applied to detect Methylene blue (MB) in river water, and the detection limit (1.0 × 10?8 M) can be acquired. Pyrene is also chosen as probe molecule, and quantitative determination is achieved with detection limit of 1.0 × 10?7 M. These demonstrate the well feasibility for multi-molecule detection. Furthermore, the nanocomposite displays high stability, reproducible stability, and acid and alkali resistance.
关键词： Organic pollutants,Plasmonic effect,SERS,Graphene oxide,Detection,MoO2
更新于2025-11-14 15:27:09
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Graphene oxide/ZnO nanorods/graphene oxide sandwich structure: The origins and mechanisms of photoluminescence
摘要： In this paper, we present the structural and optical properties of Graphene oxide/ZnO nanorods/graphene oxide (GO/ZnO nanorods/GO) nanocomposites prepared via a hydrothermal method on Si (100) substrate. The X-ray diffraction measurements (XRD) confirm that the prepared samples are of hexagonal wurtzite structure with crystallite size around 50-60 nm. It was obvious from scanning electron microscopy (SEM) that by incorporating the ZnO nanorods between the inter-layer of GO confirmed the formation of sandwich-like nanocomposites structure. ZnO nanorods interaction with GO is displayed by the different vibrational frequencies in fourier transform infrared spectroscopy (FTIR). The UV-Vis spectrum reveals the strongest absorption was observed around 370 nm, while calculating optical band gap energy (Eg) of GO/ZnO NRs/GO was found to be 3.15 eV. The photoluminescence (PL) measurements indicates that the ZnO nanorods have a strong visible emission centered at 559 nm attributed to the presence of impurities in the form of oxygen vacancies. After the nanorods were covered with GO layers, the PL intensity of the nanocomposite is quenched and shifted due to charge-transfer process. Consequently, the obtained results may lead to better performance for the optoelectronic applications.
关键词： ZnO nanorods,hydrothermal method,excitation effect,graphene oxide
更新于2025-11-14 15:25:21
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Lossy Mode Resonance Generation by Graphene Oxide Coatings onto Cladding-Removed Multimode Optical Fiber
摘要： In this work, we have studied the suitability of graphene oxide-based thin films to be not only excellent sensitive coatings but also lossy mode resonance (LMR)-generating materials. Thin films of graphene oxide (GO) and polyethylenimine (PEI) fabricated by means of layer-by-layer assembly were selected in this study. Two optical fiber devices with 8 and 20 bilayers of the LMR-generating coating were fabricated and characterized as refractometers. Both devices show no hysteresis and high sensitivity, improving previously reported values. This research opens very promising and exciting possibilities in the field of optical fiber sensors based on LMR, strategically including specific recognition groups to the device surface to exploit this high sensitivity for monitoring a range of target analytes. The carboxylate functional groups at the edges of the GO sheets should provide excellent attachment sites for the required coupling chemistry to realize such devices.
关键词： optical fiber sensor,thin films,Dip-assisted layer by layer,lossy mode resonance,refractometer,graphene oxide
更新于2025-11-14 15:19:41
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Tuning the electrical properties of graphene oxide by nitrogen ion implantation: Implication for gas sensing
摘要： Tailoring the electrical properties of graphene oxide (GO) is one of the important requirements for its application in future electronic devices. A modified Hummer’s method was employed in the preparation of GO and spray coated on glass substrates, subsequently drying at 60 °C for 6 h. The as prepared samples were implanted with 100 keV nitrogen ions at the fluences of 1E15, 5E15 and 1E16 ions/cm2. A peak shift to higher 2θ in XRD pattern indicates the reduction of GO to rGO after N ion implantation. The intensity ratio of G and D bands (IG/ID) for GO derived from the Raman analysis increased from 0.97 to 1.02 after implantation (1E16 ions/cm2). The EDS analysis confirms the implantation of N ions in GO. The electrical conductivity improved as a function of fluence, and observed to be high for the sample of 1E16 ions/cm2, and is tested for methanol sensing. Concentration dependent methanol sensing shows 5.9% response for 300 ppm. Above results show that ion implantation is a promising method for controlled reduction of GO for tuning the electrical properties.
关键词： Ion implantation,Gas sensing,Graphene oxide,Reduced graphene oxide
更新于2025-09-23 15:23:52
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Graphene oxide-based zirconium oxide nanocomposite for enhanced visible light-driven photocatalytic activity
摘要： In the present investigation, an efficient visible light-active, graphene oxide-based zirconium oxide nanocomposite (GO–ZrO2) has been synthesized by co-precipitation method. The synthesized photocatalyst was characterized by XRD, FTIR, FE-SEM, EDS, TEM, TGA, PL, UV-DRS and BET surface area analysis. The characterization results illustrate the homogeneous dispersion of ZrO2 nanoparticles in the GO–ZrO2 nanocomposite with excellent harmony between GO and ZrO2 nanoparticles. The photocatalytic efficiency of the synthesized GO–ZrO2 nanocomposite was evaluated by photodegradation of hazardous, water-soluble rhodamine B and methylene blue dyes under visible light irradiation. The 90% photocatalytic degradation of rhodamine B dye (with initial conc. 30 mg/L) was observed in 105 min of visible light irradiation, while 99.23% of methylene blue (with initial conc. 100 mg/L) dyes degradation was observed in just 60 min using 25 mg/100 ml dose of GO–ZrO2 nanocomposite as a photocatalyst. The mechanistic investigation using scavengers suggest that the superoxide (O2·?) is the most reactive species involved in the photodegradation of organic dyes. The synthesized photocatalyst GO–ZrO2 nanocomposite also exhibits excellent thermal stability and reusability.
关键词： Methylene blue,Rhodamine B,Photocatalytic activity,Zirconium oxide,Graphene oxide,Visible light,Co-precipitation method
更新于2025-09-23 15:23:52
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Two-step synthesis of reduced graphene oxide with columnar-shaped ZnO composites and their photocatalytic performance with natural dye
摘要： Composites of ZnO with reduced graphene oxide were prepared in two-step synthesis process with constant temperature in variation with pH values. The synthesized composites were characterized and the results suggest that ZnO structure in the composites has a columnar morphology with an average diameter ranging 0.8–1.57 μm. The obtained properties of the composites with the present method confirmed that the material morphology influences the absorption and photocatalytic activity of natural dye under sunlight irradiation. The result shows that the maximum degradation efficiency is 64.40% achieved in 120 min.
关键词： Zinc oxide,Columnar morphology,Photocatalytic activity,Reduced graphene oxide,Natural dye
更新于2025-09-23 15:23:52