Materials Chemistry addresses inorganic-, organic-, and nano-based materials from a structure vs. property perspective. The second edition continues to offer innovative coverage and a practical ...approach throughout the text.
Graphitic carbon nitride (g-C3N4) behaving as a layered feature with graphite was indexed as a high-content nitrogen-doping carbon material, attracting increasing attention for application in energy ...storage devices. However, poor conductivity and resulting serious irreversible capacity loss were pronounced for g-C3N4 material due to its high nitrogen content. In this work, magnesiothermic denitriding technology is demonstrated to reduce the nitrogen content of g-C3N4 (especially graphitic nitrogen) for enhanced lithium storage properties as lithium ion battery anodes. The obtained nitrogen-deficient g-C3N4 (ND-g-C3N4) exhibits a thinner and more porous structure composed of an abundance of relatively low nitrogen doping wrinkled graphene nanosheets. A highly reversible lithium storage capacity of 2753 mAh/g was obtained after the 300th cycle with an enhanced cycling stability and rate capability. The presented nitrogen-deficient g-C3N4 with outstanding electrochemical performances may unambiguously promote the application of g-C3N4 materials in energy-storage devices.
Novel g-C3N4/CoO nanocomposite application for photocatalytic H2 evolution were designed and fabricated for the first time in this work. The structure and morphology of g-C3N4/CoO were investigated ...by a wide range of characterization methods. The obtained g-C3N4/CoO composites exhibited more-efficient utilization of solar energy than pure g-C3N4 did, resulting in higher photocatalytic activity for H2 evolution. The optimum photoactivity in H2 evolution under visible-light irradiation for g-C3N4/CoO composites with a CoO mass content of 0.5 wt % (651.3 μmol h–1 g–1) was up to 3 times as high as that of pure g-C3N4 (220.16 μmol h–1 g–1). The remarkably increased photocatalytic performance of g-C3N4/CoO composites was mainly attributed to the synergistic effect of the junction or interface formed between g-C3N4 and CoO.
Herein, we report the electrochemical Li intake capacity of carbonaceous one-dimensional graphene nanoribbons (GNRs) obtained by unzipping pristine multiwalled carbon nanotubes (MWCNTs). We have ...found that nanotubes with diameters of ∼50 nm present a smaller reversible capacity than conventional mesocarbon microbead (MCMB) powder. Reduced GNRs improve the capacity only marginally over the MCMB reference but present a lower Coulombic efficiency as well as a higher capacity loss per cycle. Oxidized GNRs (ox-GNRs) outperform all of the other materials studied here in terms of energy density. They present a first charge capacity of ∼1400 mA h g−1 with a low Coulombic efficiency for the first cycle (∼53%). The reversible capacity of ox-GNRs is in the range of 800 mA h g−1, with a capacity loss per cycle of ∼3% for early cycles and a decreasing loss rate for subsequent cycles.
Ultrathin graphitic carbon nitride (g-C
3
N
4
) nanosheets were synthesized
via
thermal exfoliation of bulk urea-derived g-C
3
N
4
under an argon atmosphere. As a visible-light responsive ...photocatalyst, this material exhibits a much superior photocatalytic activity in pollution degradation and H
2
evolution than bulk g-C
3
N
4
, as a result of the extended region of visible light response and the enhanced surface area of ultrathin g-C
3
N
4
nanosheets. These findings may provide a promising and facile approach to the design of high-performance photocatalysts.
Ultrathin graphitic carbon nitride (UGCN) nanosheets with an extended region of visible light response and enhanced surface area were constructed for a significant enhancement in photocatalysis.
Cellulose-based carbon aerogels as biodegradable and renewable biomass materials have presented potential applications in oil/water separation. Herein, a novel carbon aerogel composed of natural ...microfibrils/regenerated cellulose (NM/RCA) was directly prepared by economical hardwood pulp as raw material using a novel co-solvent composed of deep eutectic solvent (DES) and N-methyl morpholine-N-oxide monohydrate (NMMO·H2O). In addition, the morphology and structure of the filiform natural microfibers could be remained after carbonized at 400 ℃, which resulted in a low density (8–10 mg cm−3), high specific surface area (768.89 m2 g−1) and high sorption capability. In addition, the aerogel exhibited high compressibility, outstanding elasticity, excellent fatigue resistance, and recyclability (80.5% height recovery after repeating 100 cycles at the strain of 80%). Due to the morphology and composition of the carbonized microfiber surface, the superhydrophobic materials with a water contact angle of 151.5°, could sorb various oils and organic solvents with 65–133 times its own weight and maintain 91.9% sorption capacity after 25 cycles. In addition, the aerogels could achieve the continuous separation of carbon tetrachloride (CCl4) from water with a high flux rate of 11,718.8 L m−2 h−1. Therefore, our prepared NM/RCA aerogels are anticipated to have broad potential applications in oil purification and contaminant remediation.
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•Natural microfibrils/regenerated cellulose carbon aerogels are fabricated.•The natural cellulose fibers are fixed by lamellar regenerated cellulose.•The excellent sorption capacity of NM/RCA for oil is up to 65.4–131 g g−1.•NM/RCA shows high separation efficiency of oil/water mixture ≥ 99.94%.
Z-scheme heterostructure g-C3N4/PSi photocatalysts were constructed successfully by loading PSi particles on g-C3N4 nanosheets to enhance photocatalytic H2 evolution performance, resulting form ...improved separation rate of photogenerated charge carries associated with the construction of heterostructure at the interface.
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•Z-scheme heterostructure g-C3N4/PSi photocatalysts were constructed by loading PSi.•The constructed Z-scheme g-C3N4/PSi exhibit enhanced photocatalytic H2 evolution activity.•The synergistic effect between g-C3N4 and PSi is responsible for the enhanced activity.
In this work, Z-scheme heterostructure were constructed over the visible light response g-C3N4 photocatalysts by loading Porous silicon (PSi) to enhance the photocatalytic H2 evolution performance. The synthesized Z-scheme g-C3N4/PSi composites with a PSi loading content of 2.50 wt% achieves the highest photocatalytic H2 evolution rate at 870.4 µmol h−1 g−1, which is about 2 times as high as the pure g-C3N4 with H2 evolution rate of 427.2 µmol h−1 g−1. Various techniques including XRD, SEM, TEM, FTIR, XPS, UPS, PL and electrochemical method were employed to demonstrate the successful construction of g-C3N4/PSi composites and to investigate the origin of the enhanced potocatalytic activity. The formed heterostructure between g-C3N4 nanosheets and PSi were verified to be the dominant reason for the enhancement of photocatalytic activity, resulting from the separation promotion of photogenerated charge carriers in a direct Z-scheme mechanism. This study presented a promising Z-scheme g-C3N4/PSi photocatalysts with promising H2 evolution performance, which might drive the progress of solar energy conversion technologies.
Layered porous MoS2 with high adsorption capacity was synthesized directly using molybdenum trioxide and potassium rhodanate as Mo and S sources in a facile hydrothermal method without any surfactant ...and sacrificial template. The influences of varying the hydrothermal temperature on the morphology and adsorptive properties of MoS2 are discussed. As-prepared MoS2 samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible spectrophotometry (UV-Vis), room-temperature photoluminescence spectroscopy (RT-PL), thermogravimetric analysis (TGA) and Brunauer-Emmet-Teller (BET) measurements. MoS2 samples exhibited an optimal nanostructure, specific surface area and thermal stability when the hydrothermal temperature was 190 degree C, and the layered porous structure is comprised of many thin nanosheets. In addition, the final adsorption capacities of the layered MoS2 toward RhB, MB and MO were studied. The sample exhibited ultrafast adsorption for dye removal and could reach 163.0 mg g-1, 499.0 mg g-1 and 125.1 mg g-1 at 420 min, respectively. The adsorption mechanism was also studied. The results indicate that layered MoS2 structures possess a significant adsorption ability, which may be useful for further research and practical applications of the layered MoS2 adsorbent in wastewater treatment.
With high capacities, as well as controllable morphologies and compositions, doped carbons represent attractive options for metal-ion battery electrode materials. In this work, we demonstrated a ...facile one-pot, one-step production of nitrogen-doped porous carbon (NPC) from an abundant and inexpensive urea precursor. The unique porous structure composed of an abundance of graphene nanosheets with high nitrogen doping level for the obtained NPC materials resulted in very promising electrochemical performances when used in lithium-ion batteries (LIBs). A high reversible lithium storage capacity of 1781 mAh/g was obtained after 500th cycle, with an enhanced cycling stability and rate capability. The method presented in this work may provide a simple, clean, economical and scalable strategy for production of NPC as a feasible and promising anode material for energy storage applications.
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