New Carbon Materials最新文献

The nitrate reduction reaction (NtRR) has been demonstrated to be a promising way for obtaining ammonia (NH₃) by converting NO₃⁻ to NH₃. Here we report the controlled synthesis of cobalt tetroxide/graphdiyne heterostructured nanowires (Co₃O₄/GDY NWs) by a simple two-step process including the synthesis of Co₃O₄ NWs and the following growth of GDY using hexaethynylbenzene as the precursor at 110 °C for 10 h. Detailed scanning electron microscopy, high resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman characterization confirmed the synthesis of a Co₃O₄/GDY heterointerface with the formation of sp-C―Co bonds at the interface and incomplete charge transfer between GDY and Co, which provide a continuous supply of electrons for the catalytic reaction and ensure a rapid NtRR. Because of these advantages, Co₃O₄/GDY NWs had an excellent NtRR performance with a high NH₃ yield rate (Y_NH3) of 0.78 mmol h⁻¹ cm⁻² and a Faraday efficiency (FE) of 92.45% at −1.05 V (vs. RHE). This work provides a general approach for synthesizing heterostructures that can drive high-performance ammonia production from wastewater under ambient conditions.

Molybdenum selenide (MoSe₂) has been regarded as an advanced electrocatalyst for the hydrogen evolution reaction (HER). However, its electrocatalytic performance is far inferior to platinum (Pt). Combining semiconductors with metals to construct Mott-Schottky heterojunctions has been considered as an effective method to enhance HER activity. In this work, we report a typical Mott-Schottky heterojunction composed of metal Co and semiconductor MoSe₂ on carbon nanotubes (Co/MoSe₂@CNT), prepared by a sol-gel process followed by thermal reduction. The characterization and theoretical calculations show that a Co/MoSe₂ Mott-Schottky heterojunction can cause electron redistribution at the interface and form a built-in electric field, which not only optimizes the free energy of hydrogen atom adsorption, but also improves the charge transfer efficiency during hydrogen evolution. Thus, the Co/MoSe₂@CNT has excellent catalytic activity with a low overpotential of 185 mV at 10 mA cm⁻² and a small Tafel slope of 69 mV dec⁻¹. This work provides a new strategy for constructing Co/MoSe₂ Mott-Schottky heterojunctions and highlights the Mott-Schottky effect, which may inspire the future development of more attractive Mott-Schottky electrocatalysts for H₂ production.

Metal-air batteries have received significant attention as highly efficient energy conversion and storage devices. Nevertheless, several difficulties, such as the sluggish reaction kinetics of the cathode and the high cost of precious metals, have significantly hampered their commercialization. Biomass carbon materials have emerged as an important alternative for the development of high-performance cathode materials in metal-air batteries, owing to their remarkable electrochemical characteristics, environmental friendliness and cost effectiveness. In recent years, there has been huge progress in the preparation and design of biomass carbon materials. This review summarizes the most recent research on these materials, and the effects of the reaction mechanism, synthesis method and multidimensional (1D, 2D, 3D) structure on their electrocatalytic performance are reviewed. Finally, problems associated with their use and possible new developments are discussed. The review presents new perspectives on the structure of these materials, and provides a basis for the development of efficient, affordable, and stable cathode materials for metal-air batteries.

A commercial polypropylene (PP) separator was modified by a one-dimensional carbon nanotube (CNT) and two-dimensional montmorillonite (MMT) hybrid material (CNT-MMT). Because of the high electron conductivity of the CNTs, and the strong polysulfide (LiPS) adsorption ability and easy lithium ion transport through MMT, the interconnected porous CNT-MMT interlayer with excellent structural integrity strongly suppresses LiPS shuttling while maintaining high lithium-ion transport, producing a high utilization of the active sulfur. Lithium-sulfur batteries assembled with this interlayer have a high lithium-ion diffusion coefficient, a high discharge capacity and stable cycling performance. They had an initial specific capacity of 1 373 mAh g⁻¹ at 0.1 C, and a stable cycling performance with a low decay rate of 0.062% per cycle at 1 C after 500 cycles.

Because of their high electrochemical activity, good structural stability, and abundant active sites, multi-metal sulfide/carbon (MMS/C) composites are of tremendous interest in diverse fields, including catalysis, energy, sensing, and environmental science. However, their cumbersome, inefficient, and environmentally unfriendly synthesis is hindering their practical application. We report a straightforward and universal method for their production which is based on homogeneous multi-phase interface engineering. The method has enabled the production of 14 different MMS/C composites, as examples, with well-organized composite structures, different components, and dense heterointerfaces. Because of their composition and structure, a typical composite has efficient, fast, and persistent lithium-ion storage. A ZnS-Co₉S₈/C composite anode showed a remarkable rate performance and an excellent capacity of 651 mAh·g⁻¹ at 0.1 A·g⁻¹ after 600 cycles. This work is expected to pave the way for the easy fabrication of MMS/C composites.

Carbon/carbon-silicon carbide (C/C-SiC) composites were prepared by impregnation, hot-pressing with curing, carbonization at 800 ^oC and high-temperature heat treatment (800-1600 ^oC) using a 2D laminated carbon cloth as the reinforcing filler, and furfurone resin mixed with silicon, carbon from furfurone resin and SiC powders as the matrix. The effects of the addition of the three powders as well as subsequent chemical vapor infiltration (CVI) by methane on the density, microstructure and bend strength of the composites were investigated by scanning electron microscopy, density measurements, X-ray diffraction and mechanical testing. Both the SiC powders formed by the reaction at 1 600 ^oC between the added Si and C particles and the added SiC powder, play a role in the reinforcement of the materials. In three-point bending, the composites had a pseudoplastic fracture mode and showed interlaminar cracking. After 10 h CVI with methane, pyrolytic carbon was formed at the interface between some of the carbon fibers and the resin carbon matrix, which produced maximum increases in the density and flexural strength of the composites of 4.98% and 38.86%, respectively.

Advanced electromagnetic absorbing materials (EAMs) with strong absorption and a wide effective absorption bandwidth (EAB), using innovative microstructural design and suitable multicomponents remain a persistent challenge. Here, we report the production of a material by the hydrothermal reduction of a mixture of graphene oxide (GO), Ni(NO₃)₂·6H₂O, and Co(NO₃)₂·6H₂O, resulting in reduced GO (RGO) with a self-assembled 3D mesh structure filled with NiCo₂(CO₃)₃. The unique microstructure of this assembly not only solves the problem of NiCo₂(CO₃)₃ particles agglomerating but also changes the electromagnetic parameters, thereby improving the impedance matching and attenuation ability. High electromagnetic wave absorption (EMA) was achieved by combining the 3D interconnected mesh structure and the various interfaces between NiCo₂(CO₃)₃ and RGO. The minimal reflection loss (RL_min) was −58.5 dB at 2.3 mm, and the EAB was 6.5 GHz. The excellent EMA performance of the aerogel can be attributed to the multiple reflection, scattering, and relaxation process of the porous 3D structure as well as the strong polarization of the interfacial matrix.

The interfacial shear strength (IFSS) between carbon fibers (CFs) and the matrix is crucial to the performance of CF-reinforced polymer composites. To evaluate the contribution of mechanical interlocking and chemical anchoring at the interfaces of a polyacrylonitrile-based CF (TORAYCA T800SC-12000-10E)-reinforced epoxy resin (EP: bisphenol A type epoxy resin and tetrafunctional epoxy resin) composites, the surface roughness and content of oxygen-containing functional groups of the CFs were respectively altered by ammonia treatment and electrochemical oxidation. The results showed that ammonia treatment increased the surface roughness without much change to the surface elemental composition, while electrochemical oxidation increased the number of surface oxygen groups without changing the surface roughness. The IFSS of CF/EP composites was tested by the micro-droplet method. The relationships between IFSS, and surface roughness and oxygen content were obtained by linear fitting. The results showed that in the interfacial bonding of CF to epoxy resin, the contribution of chemical anchoring to the IFSS is larger than that of mechanical interlocking.

We report a method for the of coal-based fluorescent carbon dots (CDs) at room temperature using a mixture of hydrogen peroxide (H₂O₂) and formic acid (HCOOH) as the oxidant instead of concentrated HNO₃ or H₂SO₄. The CDs have an excitation dependent behavior with a high quantum yield (QY) of approximately 7.2%. The CDs are water soluble and have excellent photo-stability, good resistance to salt solutions, and are insensitive to pH in a range of 2.0-12.0. The CDs were used as a very sensitive probe for the turn-off sensing of Fe³⁺ ion with a detection limit as low as 600 nmol/L and a detection range from 2 to 100 μmol/L. This work provides a way for the high value-added utilization of coal.

Solar-driven interfacial vapor generation (SIVG) is increasingly used for fresh water production, having the advantages of low energy consumption, eco-friendliness, and high efficiency. Carbon-based photothermal materials (CPTMs) can introduce temperature and salinity gradients in the SIVG process because of their outstanding photothermal conversion properties, which have given SIVG great potential for both steam and power generation. Various kinds of CPTMs for clean water and electricity generation are discussed in this review. The basic principles and key performance indices of SIVG are first described and the photothermal and SIVG performance of various CPTMs including graphene oxides, carbon nanotubes, carbon dots and carbonized biomass are then summarized. Finally, current research concerning water/electricity cogeneration and ways to deal with the problems encountered are presented, to provide some guidelines for the use of multifunctional CPTMs for simultaneous steam and electricity generation.