Strain sensors with excellent flexibility, stretchability, and sensitivity have attracted increasing interests. In this paper, a highly stretchable and ultrasensitive strain sensor based on reduced graphene oxide microtubes-elastomer is fabricated by a template induced assembly and followed a polymer coating process. The sensors can be stretched in excess of 50% of its original length, showing long-term durability and excellent selectivity to a specific strain under various disturbances. The sensitivity of this sensor is as high as 630 of gauge factor under 21.3% applied strain; more importantly, it can be easily modulated to accommodate diverse requirements. Implementation of the device for gauging muscle-induced strain in several biological systems shows reproducibility and different responses in the form of resistance or current change. The developed strain sensors show great application potential in fields of biomechanical systems, communications, and other related areas.

Hollow polyhedrons were structured from carbon-coated CoSe2 nanospheres bridged by CNTs, and showed a boosted rate capability/robust cyclability for sodium storage.

The desired control of size, structure, and optical properties of fluorescent carbon dots (CDs) is critical for understanding the fluorescence mechanism and exploring their potential application. Herein, a top-down strategy to chemically tailor the inexpensive coal to fluorescent CDs by a combined method of carbonization and acidic oxidation etching is reported. The size and optical properties of the as-made CDs are tuned by controlling the structures of graphitic crystallites in the starting precursor. The coal-derived CDs exhibit two different distinctive emission modes, where the intensity of the short-wavelength emission is significantly enhanced by partial reduction treatment. The evolution of the electronic structure and the surface states analysis show that two different types of fluorescence centers, nano-sized sp(2) carbon domains and surface defects, are responsible for the observed emission characteristics. The reduced CDs are demonstrated as an effective fluorescent sensing material for label-free and selective detection of Cu(II) ions with a detection limit as low as 2.0 nM, showing a great promise for real-world sensor applications.

Coal has been used as an important resource for the production of chemicals, conventional carbon materials, as well as carbon nanomaterials with novel structures, in addition to its main utilization in the energy field. In this work, we present the synthesis of chemically derived graphene and graphene−noble metal composites with coal as the starting material by means of catalytic graphitization, chemical oxidation, and dielectric barrier discharge (DBD) plasma-assisted deoxygenation. It is found that the graphitization degree of the coal-derived carbon remarkably affects the properties of graphene obtained from chemical exfoliation, and high crystallinity of coal-derived carbon is essential for the preparation of high-quality graphene sheets (GS). GS decorated with highly dispersed noble metallic nanoparticles (NP) on their surface (NP/GS) were successfully fabricated via simultaneous reduction of graphite oxide (GO) and noble metal salts by H 2 DBD plasma technique. The electrochemical performance of the GS as electrode in supercapacitor and the catalytic activities of NP/GS composites in selective reduction of nitrogen oxides (NO x ) were investigated. This work demonstrates an alternative approach for the fabrication of graphene and its composites from coal with promising potential in energy storage and environment preservation.

Sodium ion batteries (SIBs) have been considered as a promising alternative to lithium ion batteries, owing to the abundant reserve and low-cost accessibility of the sodium source. To date, the pursuit of high-performance anode materials remains a great challenge for the SIBs. In this work, carbon-stabilized interlayer-expanded few-layer MoSe nanosheets (MoSe@C) have been fabricated by an oleic acid (OA) functionalized synthesis-polydopamine (PDA) stabilization-carbonization strategy, and their structural, morphological, and electrochemical properties have been carefully characterized and compared with the carbon-free MoSe. When evaluated as anode for sodium ion half batteries, the MoSe@C exhibits a remarkably enhanced rate capability of 367 mA h g at 5 A g, a high reversible discharge capacity of 445 mA h g at 1 A g, and a long-term cycling stability over 100 cycles. To further explore the potential applications, the MoSe@C is assembled into sodium ion full batteries with NaV(PO) (NVP) as cathode materials, showing an impressively high reversible capacity of 421 mA h g at 0.2 A g after 100 cycles. Such results are primarily attributed to the unique carbon-stabilized interlayer-expanded few-layer MoSe nanosheets structure, which facilitates the permeation of electrolyte into the inner of MoSe nanosheets, promoting charge transfer efficiency among MoSe nanosheets, and accommodating the volume change from discharge-charge cycling.

No abstract

No abstract

Dually fixed SnO2 nanoparticles (DF-SnO2 NPs) on graphene nanosheets by a polyaniline (Pani) coating was successfully fabricated via two facile wet chemistry processes, including anchoring SnO2 NPs onto graphene nanosheets via reducing graphene oxide by Sn(2+) ion, followed by in situ surface sealing with the Pani coating. Such a configuration is very appealing anode materials in LIBs due to several structural merits: (1) it prevents the aggregation of SnO2 NPs, (2) accommodates the structural expanding of SnO2 NPs during lithiation, (3) ensures the stable as-formed solid electrolyte interface films, and (4) effectively enhances the electronic conductivity of the overall electrode. Therefore, the final DF-SnO2 anode exhibits stable cycle performance, such as a high capacity retention of over 90% for 400 cycles at a current density of 200 mA g(-1) and a long cycle life up to 700 times at a higher current density of 1000 mA g(-1).