- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Environmentally Benign Metal-Free Reduction of GO Using Molecular Hydrogen: A Mechanistic Insight
摘要： A simple yet effective methodology to obtain high-quality reduced graphene oxide (RGO) using a tetrahydrofuran suspension of GO under hydrogen at moderate pressure has been demonstrated. The extent of reduction as a function of the pressure of hydrogen gas, temperature, and time was studied, where the abstraction of oxygen is achievable with least mutilation of C-sp2 bonds, hence upholding the integrity of the graphene sheet. Herein, the formation of a short-lived species is proposed, which is possibly responsible for such reduction. A detailed theoretical calculation along with in situ UV?visible experiments reveals the existence of a transient solvated electron species in the reaction medium. The hydrogen RGO (HRGO) achieved a C/O atomic ratio of 11.3. The conductivity measurements show that HRGO reached as high as 934 S/m, which indicates a high quality of RGO. The process is hassle-free, environmentally benign, and can be scaled up effortlessly without compromising the quality of the material.
关键词： reduced graphene oxide,high-quality RGO,environmentally benign,hydrogen reduction,solvated electron
更新于2025-09-23 15:21:21
-
Laser Reduction of Graphene Oxide/Zinc Oxide Nanoparticle Nanocomposites as a Onea??Step Process for Supercapacitor Fabrication
摘要： Herein, the laser reduction of graphene oxide (GO) and zinc oxide nanoparticle (ZnONP) nanocomposite ?lms is proposed as a one-step process for supercapacitor fabrication. The ?lms, deposited by casting onto a ?exible poly(ethylene terephthalate) (PET) substrate coated with indium-doped tin oxide (ITO), are subjected to laser irradiation (5 mW, 405 nm) to reduce the GO phase and produce laser-reduced GO (LRGO). Scanning electron microscopy/energy dispersion spectroscopy (SEM–EDS), micro-Raman spectroscopy, and current versus voltage (I(cid:1) V) analyses show a partial reduction of GO to LRGO, forming several conductor-insulating (LRGO/GO) microporous interfaces, and thereby favoring the formation of a supercapacitor structure. Moreover, the topmost LRGO ?lm layer is extensively reduced, making it suf?ciently conducting to work as the counter electrode as well. However, the reduction process is less effective when ZnONPs are introduced into the GO matrix because ZnONPs get clustered and scatter the incident laser before reaching the GO phase. The capacitive behavior, assessed by cyclic voltammetry and galvanostatic charge–discharge measurements, reveals the following (cid:3)1 (GO/LRGO/ ZnONP). The method proposed herein is advantageous because it produces the microcapacitor structures and LRGO counter electrode in a single laser reduction step.
关键词： laser-reduced graphene oxide,graphene oxide,nanocomposites,micro-heterojunctions,zinc oxide nanoparticles
更新于2025-09-23 15:21:01
-
New fabrication method for producing reduced graphene oxide flexible electrodes by using low-power visible laser diode engraving system
摘要： The fabrication of bendable electronic devices is being a scientific-technological area of very rapid advance in which new materials and fabrication techniques are being continuously developed. In this kind of devices, the fabrication of flexible conductive electrodes adherent to the substrate is a key factor. Besides, eco-friendliness, low cost and fast production are essential requirements for the successful progress of new technologies. In this work, a novel method for obtaining graphene-based flexible electrodes is presented. Conductive films were obtained by means of visible laser irradiation of graphene oxide layers deposited on polyethylene terephthalate substrates besides self-standing membranes sandwiched between glass slides. Despite the low power of the laser system, numerical simulations indicate the development of temperatures over 1000 K throughout the irradiated material. The laser-induced spatially confined heating leads to the reduction of the graphene oxide material whereas the glass-based sandwich assembly avoids reoxidation from surrounding air. By scanning and pixelated modes, reduced graphene oxide electrodes, up to 100 μm in thickness, and with resistivity as low as 6×10-4 ?m were obtained in an easy and versatile way. Proof-of-concept microsupercapacitors and electrochemical sensors were fabricated with this technique, showing promising performance.
关键词： laser fabrication,flexible electrode,laser-reduced graphene oxide,graphene electrode
更新于2025-09-23 15:21:01
-
Surface Engineered Hybrid Corea??Shell Sia??Nanowires for Efficient and Stable Broadband Photodetectors
摘要： Silicon nanostructures have gained intensive interest to develop broadband photodetectors at a large-scale due to their excellent electronic properties. Herein, Si-nanowires (SiNWs) decorated with reduced graphene oxide:carbon quantum dots (rGO:CQDs) nanocomposite (NC), as core–shell heterojunction building blocks for broadband (ultraviolet (UV)–near infrared (NIR)) photodetectors (PDs), are demonstrated. The SiNWs and CQDs are synthesized by wet-chemical etching and facile pyrolysis methods, respectively. Photogenerated carriers are transported through rGO because of its high electron mobility and favorable band alignment with CQDs and Si. Further, to minimize the recombination of photogenerated carriers, and enhance the response in the visible region, plasmon-enhanced AuCQDs are incorporated in the shell matrix. The optimized heterostructure (rGO:AuCQDs/undoped CQDs/SiNWs) is sensitive to a broad wavelength range covering the UV to NIR (360 to 940 nm) region, manifests the excellent responsivity of 16 A W?1 at 360 nm, detectivity (D*) of 2.2 × 1013 Jones, and noise equivalent power as low as 2.8 fW Hz?1/2. The optimized PDs heterostructure demonstrates excellent air-stability after 8 days of illumination without any encapsulation or protective coating. The proposed simple, cost-effective, and Si-process-line compatible fabrication of Si-based PD device structure imposes a great promise for highly efficient and stable advanced futuristic optoelectronic devices.
关键词： core–shell heterostructure,detectivity,responsivity,broadband photodetectors,reduced graphene oxide,carbon quantum dots,Si nanowires
更新于2025-09-23 15:21:01
-
Monodispersed Nickel Phosphide Nanocrystals In Situ Grown on Reduced Graphene Oxide with Controllable Size and Composition as Counter Electrode for Dye-Sensitized Solar Cells
摘要： Owing to their abundance, low cost and excellent functional properties and catalytic activity, transition metal phosphides (TMPs) have been proposed in a broad range of energy conversion technologies. However, their challenging synthesis and moderate electrical conductivity has limited their implementation in real applications. Here, we detail a simple procedure to grow fully dispersed nickel phosphide nanocrystals (NCs) with controlled size, phase and composition on the surface of reduced graphene oxide (rGO). The resultant NixPy/rGO composites effectively combine a huge density of catalytic active sites from NixPy with the excellent conductivity of rGO, thus exhibiting highly improved electrocatalytic activities. NixPy/rGO composites were tested as counter electrode (CE) in dye sensitized solar cells (DSSCs), providing significantly improved performance over conventional Pt-based CEs. The incorporation of CEs based on Ni12P5/rGO composites allowed reaching power conversion efficiency up to 8.19%, well above those of DSSCs based Pt CEs (7.87%). According to DFT calculations, the outstanding electrocatalytic activity of Ni12P5/rGO as CE in DSSCs was associated with the exceptional I3ˉ adsorption capacity. These results prove that Ni12P5/rGO is a promising candidate to replace Pt as CE in DSSCs.
关键词： Reduced graphene oxide,Dye-sensitized solar cells,Nickel phosphide,Electrocatalytic activity,Monodispersed
更新于2025-09-23 15:21:01
-
Fabrication of Ag nanoparticles adhered on RGO based on both electrodes in dye-sensitized solar cells (DSSCs)
摘要： The electrode plays an important role in dye-sensitized solar cells (DSSCs). Preparation of the electrode should be simple and should result in high performance of its DSSC. We herein demonstrated high-performance and easily prepared Silver nanoparticles adhered on Reduced graphene oxide–Platinum composites (Ag–RGO/Pt) as counter electrodes (CEs) and TiO2 on RGO sheets with Ag (TiO2–RGO/Ag) as photoanode (PE) in DSSCs. The 1:2 Ag–RGO/Pt CE and 0.5% TiO2–RGO/Ag PE showed an overall highest power conversion efficiency of 9.15% under (1.5 AM) solar irradiation. The optimal weight ratio of Ag:RGO:Pt materials was also examined. Moreover, we showed that incorporation of Ag nanoparticles into the counter electrode successfully improved interfacial charge transfer resulting in high electrocatalytic activity for the reduction of triiodide to iodide redox, which in turn could enhance the performance of the DSSCs.
关键词： Counter electrode,Silver,Reduced graphene oxide,Dye-sensitized solar cells
更新于2025-09-23 15:21:01
-
A Novel Single-Atom Electrocatalyst Ti <sub/>1</sub> /rGO for Efficient Cathodic Reduction in Hybrid Photovoltaics
摘要： Single-atom catalysts (SACs) are a frontier research topic in the catalysis community. Carbon materials decorated with atomically dispersed Ti are theoretically predicted with many attractive applications. However, such material has not been achieved so far. Herein, a Ti-based SAC, consisting of isolated Ti anchored by oxygen atoms on reduced graphene oxide (rGO) (termed as Ti1/rGO), is successfully synthesized. The structure of Ti1/rGO is characterized by high-angle annular dark-field scanning transmission electron microscopy and X-ray absorption fine structure spectroscopy, being determined to have a five coordinated local structure TiO5. When serving as non-Pt cathode material in dye-sensitized solar cells (DSCs), Ti1/rGO exhibits high electrocatalytic activity toward the tri-iodide reduction reaction. The power conversion efficiency of DSCs based on Ti1/rGO is comparable to that using conventional Pt cathode. The unique structure of TiO5 moieties and the crucial role of atomically dispersed Ti in Ti1/rGO are well understood by experiments and density functional theory calculations. This emerging material shows potential applications in energy conversion and storage devices.
关键词： reduced graphene oxide,titanium,single-atom catalysts,dye-sensitized solar cells,cathode reaction
更新于2025-09-23 15:21:01
-
Enhanced photocatalytic activity based on TiO <sub/>2</sub> hollow hierarchical microspheres/reduced graphene hybrid
摘要： A novel TiO2 hollow hierarchical microspheres/reduced graphene oxide (TiO2 HHMs/rGO) hybrid was prepared by a facile and efficient two-step solvothermal synthesis method. The TiO2 HHMs with the size ～500 nm were uniformly distributed on the surface of rGO nanosheets. The as-prepared TiO2 HHMs/rGO hybrid is stable and exhibits a significantly higher photocatalytic activity (97.8%) for 40 ml of 10 mg/Rhodamine B (RhB) solution than that of the pure TiO2 microspheres (75.2%) and Degussa P25 (53.6%). The rGO nanosheet acts as a microelectrode for rapid accepting and separating the photogenerated electron on surface, which effectively slow the recombination rate of electrons and holes, and then effectively enhance the photocatalytic activity of the hybrid. The as-prepared novel TiO2 HHMs/rGO hybrid shows great promising for practical photocatalytic applications.
关键词： TiO2 hollow hierarchical microspheres/reduced graphene oxide (TiO2 HHMs/rGO) hybrid,enhancement,photocatalytic activity,two-step solvothermal synthesis
更新于2025-09-23 15:21:01
-
Programmable graphene-based humidity and heat driven actuators prepared by one-step laser direct writing
摘要： Smart materials are gathering increasing attention and play important roles in intelligent actuators, among which films with Janus structure are widely used because of their intrinsic response ability. Herein, we report a highly simplified method, laser direct writing, for preparing GO (Graphene Oxide)/rGO (Reduced Graphene Oxide) Janus films. By adjusting the output power of laser, GO homogeneous films can be accurately reduced in a single step and a certain thickness can be controllably reduced to form GO/rGO Janus films. The structure and chemical composition of the resulting GO/rGO films were characterized. Their response to ambient temperature and humidity is determined experimentally. The response performance of Janus films with different thickness was tested, and the one with thickness of 15 μm performed the best. The Janus films are made into diverse actuators, including a bionic movable creeper and a grabber that can grab a leaf upon changing the humidity in a planned way. Furthermore, we designed a finger-guessing robot that can be programmed in advance and perform the predetermined actions.
关键词： reduced graphene oxide,actuator,Janus structure,graphene oxide,laser direct writing
更新于2025-09-23 15:19:57
-
Self-assembled electrodes based on polyaniline grafted with reduced graphene oxide and polystyrene sulfonate
摘要： In this work, composites based on polyaniline (PAni) grafted with reduced graphene oxide (rGO) were obtained by the in situ chemical polymerization of aniline with rGO (mass ratio of 1 and 2.5%) dispersed into the monomer solutions. PAni and its PAni-rGO composites were used to prepare self-assembled (SA) films by depositing them onto indium tin oxide (ITO) substrates with alternating layers of polystyrene sulfonate (PSS). The structure and morphology of the materials were characterized by Fourier-transform infrared spectroscopy (FT-IR), RAMAN spectroscopy, and scanning electron microscopy (SEM). The oxidation states of PAni and its PAni-rGO composites were characterized by cyclic voltammetry (CV) and UV-Vis spectroscopy during the SA procedure. The electrochemical behavior of the obtained SA films was also characterized by electrochemical impedance spectroscopy (EIS). The EIS results showed a significant decrease in the polarization resistance (Rp), from 1020 to 302 Ω, for the film with 1% of rGO (PAni-1%rGO/PSS) when compared with its unmodified counterpart (PAni/PSS). The synergic effects observed for the PAni-1%rGO/PSS film showed that controlling the rGO mass ratio plays an important role in the improvement of the charge transfer processes, and that this electrode has potential for electrochemical applications, such as sensors and charge storage devices.
关键词： Conducting polymer composites,Polyaniline,Reduced graphene oxide,Self-assembly
更新于2025-09-23 15:19:57