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Rational design of low-cost and highly-efficient bifunctional oxygen electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is currently critical for renewable energy storage and conversion devices. Herein, we represent a series of three-dimensional porous B and N co-doped graphene aerogels (BN-GAs) using NH4B5O8 as precursor for B and N source by hydrothermal method...
In this work, through a heteroatom-doping process and the subsequent base washing strategy, a new type of metal-free nitrogen- and sulfur-codoped graphene nanoribbons (BW-NS-rGONRs) were synthesized. It was found that a considerable amount of carbonaceous oxidative debris resided in graphene oxide nanoribbons (GONRs) produced from unzipping multiwalled carbon nanotubes has a great effect on the electrocatalytic...
By taking advantage of the structural tunability of ionic liquids (ILs), a series of imidazolium ILs were employed as precursors to prepare carbon dots (IL-CDs) and as regulators to control their properties. The simultaneous formation of hydrophilic CDs (IL-HCDs) and organophilic CDs (IL-OCDs) is achieved in hydrothermal reaction system by undergoing sulfuric acid carbonization. The quantum yields...
In recent years, various doping methods for epitaxial graphene have been demonstrated through atom substitution and adsorption. Here we observe by angle-resolved photoemission spectroscopy (ARPES) a coupling-induced Dirac cone renormalization when depositing small amounts of Ti onto epitaxial graphene on SiC. We obtain a remarkably high doping efficiency and a readily tunable carrier velocity simply...
Graphene holds great promise for novel optoelectronic devices due its exceptional optical properties. Here we report an anomalous photoresponse due to resonant excitonic effects in oxygen functionalized epitaxial graphene (EG) with gain exceeding 104 in the deep-ultraviolet (DUV) region. The method used to introduce the oxygen adatoms is via mild oxygen plasma treatment. Upon oxygen adsorption, spectral...
Nitrogen-containing hollow carbon microspheres (NHCSs) are prepared by a modified template method in the presence of resorcinol/formaldehyde as carbon precursors and ethylenediamine (EDA) as both a base catalyst and nitrogen precursor. The NHCSs are used as anode materials for sodium-ion batteries, showing a superior reversible discharge capacity of 334 mAh g−1 after 100 cycles at 50 mA g−1. A high...
Graphene-based nanomaterials have been widely studied as high-performance matrices for enzyme immobilization and in the development of biosensors. Surface O-functionalities of graphene induce changes in chemical reactivity and electronic conductivity of nanomaterials and may interfere with enzymatic processes; however, the mechanisms are not fully understood. We compare the effects of three commercially...
We report semiconducting behavior of monolayer graphene enabled through plasma activation of substrate surfaces. The graphene devices are fabricated by mechanical exfoliation onto pre-processed SiO2/Si substrates. Contrary to pristine graphene, these graphene samples exhibit a transport gap as well as nonlinear transfer characteristics, a large on/off ratio of 600 at cryogenic temperatures, and an...
Designed as an anode material for sodium ion batteries, nitrogen-doped carbon sheets (NCSs) were successfully synthesized using graphene and dopamine as template and carbon precursor, respectively. The NCSs demonstrate high reversible capacity and excellent rate performance, delivering a high reversible capacity of 382mAhg−1 at 50mAg−1 after 55 cycles. Even up to 10Ag−1, a rate capacity of 75mAhg−1...
Sodium-ion batteries (SIBs) are, arguably, one of the most promising candidates for post-lithium ion battery era. The success of sodium-ion batteries is dependent on electrode materials developed. We reported here the facile preparation of carbonized filter paper decorated with Sn@C nanospheres as negative electrode materials for SIBs. The carbonized filter paper decorated with Sn@C nanospheres were...
A ferrate functionalized graphene-based composite is prepared by growth of hydrous ferric oxide (FeOOH) on the polyethylene glycol (PEG) modified graphene oxide (GO) sheets. The obtained GO–PEG–FeOOH composite is characterized by ATR-FTIR, TEM, AFM, XPS and ICP-MS. The PEGylation significantly changes the surface property of the bare graphene oxide, which not only generates a nano-bio-interface for...
Carbon fiber-reinforced carbon composites (C/C), carbon fiber reinforced-carbon and silicon carbide binary matrix composites (C/C–SiC) and carbon fiber reinforced carbon–silicon–zirconium–oxygen matrix composites (C/C–Si–Zr–O) were prepared through a combination of chemical vapor infiltration (CVI) and polymer impregnation pyrolysis. The microscopic morphology, phase structure, mechanical properties...
The photoluminescence (PL) quenching of water-soluble graphene oxide (GO) solution was systematically investigated in the presence of transition metal ions. Their PL spectra were analyzed by the Stern–Volmer equation, and the trend of the quenching efficiency was Fe2+>Co2+>Ni2+>Cd2+>Hg2+. The results of the steady-state and time-resolved PL spectra of the GO solution suggested that the...
Understanding the mechanisms controlling the differences in adsorption properties between carbon nanomaterials (CNMs) and porous carbonaceous materials—particularly, the structure–activity correlations—is critical for exploring CNMs as special adsorbents for environmental applications. In this study, batch adsorption isotherms of 4-chloronitrobenzene (planar, aromatic) to three CNMs (single-walled...
Carbonaceous materials such as activated carbon (AC) are effective adsorbents for a number of organic contaminants, and are often used in soil and sediment remediation to sequester organic contaminants. However, little is known about the abiotic reactivity (and thus, the long-term fate) of the carbonaceous material-bound contaminants. We studied the base-promoted dehydrochlorination kinetics of low-level...
As a one-atomic-layer carbon material with the symmetrical conduction and valence bands, graphene shows a lot of interesting effects under high electric field. Here, we report an observation of self-amplification effect of current in graphene transistors in high-field transport. The current in graphene transistors could increase with time and finally reaches up to the breakdown threshold of graphene,...
We present a scanning tunneling microscopy study of the stress–strain behavior of a rippled single-layer free-standing graphene (FSG) and report that FSG exhibits a non-linear sigmoidal stress–strain behavior. We managed to pull and push nanoripples by controlling the STM tip–FSG interaction forces. In this way, we found that the initial deformations of a rippled FSG involve sign reversals of the...
Mildly oxidized graphene has been prepared by O2 plasma treatments. Compared to pristine graphene, the mildly O2 plasma treated graphene can significantly enhance the Raman peaks intensities of adsorbed Rhodamine B molecules. This effect is attributed to the strong local electric field on the adsorbed molecules induced by the oxygenated species on graphene after O2 plasma treatments. The downshift...
The main objective of this study was to test the capability of CNMs to mediate the reductive dechlorination of chlorinated aliphatic hydrocarbons. We herein investigated the mediation effects of graphene oxide (GO) and multi-walled carbon nanotubes (CNT) on the reductive dechlorination of hexachloroethane by sodium sulfide in aqueous solutions (pH buffered). The presence of 10mg/L CNT or GO enhanced...
Waviness is invariably present in vertically-aligned Carbon Nanotubes (CNTs) regardless of how controlled the fabrication process is. This study, using experiments and models, shows that such inherent waviness is the main mechanism by which the effective modulus of CNTs is reduced by several orders of magnitude. At this time, most studies have shown that the compliant mechanical response of the CNT...
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