New Carbon Materials最新文献

Graphene is widely used in photodetection because of its high carrier mobility and wide spectral absorption range. However, its high dark current caused by its low light absorption severely limits its performance. Molybdenum dihalide (MoX₂, X= S, Se and Te) has a high absorption coefficient, which can compensate for the high dark current in graphene-based photodetectors and result in outstanding photoelectronic properties of those based on a graphene/MoX₂ van der Waals heterostructure (vdWH). In this review, we firstly review working principles, performance indicators, and structures of photodetectors. After that, the significance of graphene/MoX₂vdWH photodetectors is highlighted from the fundamental perspective. Preparation methodologies and performance enhancement strategies of graphene/MoX₂vdWH photodetectors are correspondingly summarized. In the end, we highlight the current challenges and future directions of the graphene/MoX₂vdWH photodetectors. This review will guide the design of high-performance vdWH photodetectors.

The electrocatalytic CO₂ reduction reaction (CO₂RR) is an environmentally friendly way to convert CO₂ into valuable chemicals. However, CO₂ conversion is a complex process, which contains 2, 4, 6, 8 and 12 electron transfer processes. It is very important to develop efficient catalysts to precisely control the number of electron transfers for the chemicals required. Single-metal catalysts have some deficiencies, including slow reaction kinetics, low product selectivity and inadequate stability. In response to these challenges, bimetallic catalysts have received significant attention owing to their unique structure and improved performance. The introduction of secondary metals alters the catalyst’s electronic structure, and creates novel active sites, as well as optimizing their interaction with the intermediates. This review provides a comprehensive account of atomically distributed bimetals based on carbon materials and non-atomic distributed bimetals such as alloys and heterostructures, including their synthesis methods, characterization, and the outcomes of different catalysts. Catalytic mechanisms of different bimetallic catalysts are proposed and challenges encountered in the CO₂RR are considered.

Exploring cost-efficient and highly-efficient noble metal-free catalysts for the oxygen reduction reactions (ORRs) involved in sustainable energy devices remains a great challenge. Transition-metal phosphides supported on heteroatom-doped carbons have shown potential as alternative candidates for precious metals because of their tunable electronic structures and higher catalytic performance. Phosphating was used to construct CoP nanoparticles (NPs) anchored on a nitrogen-doped porous carbon framework (CoP@NC) from Co NPs loaded on NC, using PH₃ gas released from NaH₂PO₂ during heat treatment. The dodecahedral structure of Co NPs was retained in their transformation to CoP NPs. The CoP@NC electrocatalyst shows a remarkable ORR activity with a half-wave potential up to 0.92 V under alkaline conditions, which is attributed to the combined coupling between the well dispersed CoP nanoparticles on the nitrogen-doped carbon and the efficient mass transport in the porous structure. Zinc-air batteries assembled with the CoP@NC electrocatalyst as a cathode have a high open-circuit voltage of 1.51 V and power density of 210.1 mW cm⁻². This work provides a novel strategy to develop low-cost catalysts with an excellent ORR performance to promote their practical use in metal-air batteries

Recent advances in the use of carbon-supported single-atom catalysts (SACs) for electrochemical reactions are comprehensively reviewed. The development and advantages of carbon-supported SACs are briefly introduced, followed by a detailed summary of the synthesis strategies used, including vapor phase transport, high temperature pyrolysis and wet chemical methods. Advanced characterization techniques for carbon-supported SACs are also reviewed. The use of carbon-supported SACs in different fields, such as the oxygen reduction reaction, carbon dioxide reduction reaction, nitrogen reduction reaction, hydrogen evolution reaction, and oxygen evolution reaction are summarized. Special emphasis is given to the modification strategies used to enable carbon-supported SACs to have an excellent electrocatalytic performance. Finally, the prospects and challenges associated with using carbon-supported SACs for electrochemical reactions are discussed.

In recent years, zinc-ion hybrid capacitors (ZIHCs) have attracted increasing attention due to their environmental friendliness and excellent electrochemical properties. However, their performance is mainly limited by the electrochemical performance of the cathode, so it is necessary to develop an advanced cathode material. N, B co-doped sodium alginate-based porous carbon (NBSPC) was prepared by one-step co-carbonization using sodium alginate as the matrix and NH₄B₅O₈ as the N and B source. This N, B co-doping strategy improves the pore structure of the carbon materials and increases the number of surface functional groups, greatly improving the capacitive behavior of the raw materials and thus improving their electrochemical performance. When used as the cathode in ZIHCs, the NBSPC had an excellent rate performance (85.4 mAh g⁻¹ even at ultra-high current density of 40 A g⁻¹) and good cycling stability (15 000 cycles at 20 A g⁻¹ with a capacity retention rate of 94.5%).

Carbon materials, including carbon nanotubes/nanofibers, graphene, graphene oxide, reduced graphene oxide, graphyne, graphdiyne, carbon quantum dots and fullerenes, have received considerable attention in recent years because of their unique properties such as high conductivity, excellent stability and biocompatibility. The integration of these materials into Z-scheme and S-scheme heterojunctions has emerged as a transformative strategy to increase their photocatalytic efficiency for energy conversion applications. We first consider the fundamental principles of clean energy generation such as photocatalytic H₂ generation and CO₂ reduction, elucidating their respective mechanisms and advantages. Various types of carbon materials, their synthesis and construction of Z-scheme and S-scheme heterojunctions are then discussed, emphasizing their role in promoting charge separation, reducing recombination losses and extending the spectral response range. With a focus on solar energy production, recent advances in carbon-based Z-scheme and S-scheme heterojunctions are discussed and summarized for photocatalytic H₂ generation and CO₂ reduction. Lastly, the current problems in the field of carbon-based photocatalysts are discussed with insights for the future development of this field.

The chlor-alkali process plays a key and irreplaceable role in the chemical industry because of its use in various industrial processes. However, the low selectivity and efficiency of the reported chlorine evolution reaction (CER) electrocatalysts obviously hinder its practical use. We report a simple method for the controlled growth of high-performance CER electrocatalysts by first growing cobalt hydroxide on the surface of carbon cloth, followed by the in-situ growth of graphdiyne (GDY/Co(OH)₂). As expected, the as-synthesized catalyst has a small overpotential of only 83 mV at 10 mA cm⁻², a maximum Faradaic Efficiency (FE) of 91.54%, and a high chlorine yield of 157.11 mg h⁻¹ cm⁻² in acidic simulated seawater. Experimental results demonstrate that the in-situ growth of GDY on the Co(OH)₂ surface leads to the formation of heterointerfaces with strong electron transfer between GDY and Co atoms, resulting in a higher conductivity, larger active specific surface area and more active sites, thereby improving the overall electrocatalytic selectivity and efficiency.

Dense graphene assemblies, composed of tightly stacked graphene sheets, have outstanding chemical stability and excellent mechanical, thermal, and electrical properties. They also do not have the problems of low density, low mechanical strength, poor electrical conductivity, or poor thermal conductivity found in porous graphene aerogels, making them ideal materials for future portable electronic and smart devices. We summarize work on high-concentration graphene oxide (GO) and graphene dispersions prepared by mechanical dispersion, evaporation concentration, centrifugal concentration, and liquid phase exfoliation, as well as two-dimensional (2D) dense graphene-based films and three-dimensional (3D) dense graphene-based structures prepared by vacuum-assisted filtration, interfacial self-assembly, and press-forming, and evaluate the advantages and disadvantages of each method. The applications of dense graphene-based assemblies in energy storage, thermal management, and electromagnetic interference (EMI) shielding are summarized. Finally, their challenges and prospects in future research are outlined. This review provides a reference for exploring and developing their large-scale, cost-effective manufacture and use.

Electromagnetic radiation has led to potentially harmful effects, and thus, there has been growing research on electromagnetic shielding materials with a wide shielding range, high absorption efficiency and stability. Graphene is a prime candidate in this field due to its low density, outstanding electrical conductivity, and large specific surface area. In this paper, we conclude the fundamental principles of electromagnetic shielding and the structural characteristics of graphene-based materials while highlighting their unique electromagnetic shielding properties. We also provide an overview of common strategies for modifying graphene-based materials, including structural modification and heteroatom doping, and their incorporation in composite materials to improve this property. Structural modification can increase the losses of electromagnetic waves by absorption and multiple reflections, and heteroatom doping and incorporation in composite materials can increase the losses by interface polarization and magnetic effects. Furthermore, we summarize various modification methods for graphene-based electromagnetic shielding materials to inspire the development of materials with lightweight and high shielding bandwidth capabilities.

It is imperative to design suitable anode materials for both lithium-ion (LIBs) and sodium-ion batteries (SIBs) with a high-rate performance and ultralong cycling life. We fabricated a MoO₂/MoS₂ heterostructure that was then homogeneously distributed in N,S-doped carbon nanofibers (MoO₂/MoS₂@NSC) by electrospinning and sulfurization. The one-dimensional carbon fiber skeleton serves as a conductive frame to decrease the diffusion pathway of Li⁺/Na⁺, while the N/S doping creates abundant active sites and significantly improves the ion diffusion kinetics. Moreover, the deposition of MoS₂ nanosheets on the MoO₂ bulk phase produces an interface that enables fast Li⁺/Na⁺ transport, which is crucial for achieving high efficiency energy storage. Consequently, as the anode for LIBs, MoO₂/MoS₂@NSC gives an excellent cycling stability of 640 mAh g⁻¹ for 2 000 cycles under 5.0 A g⁻¹ with an ultralow average capacity drop of 0.002% per cycle and an exceptional rate capability of 614 mAh g⁻¹ at 10.0 A g⁻¹. In SIBs, it also produces a significantly better electrochemical performance (reversible capacity of 242 mAh g⁻¹ under 2.0 A g⁻¹ for 2 000 cycles and 261 mAh g⁻¹ under 5.0 A g⁻¹). This work shows how introducing a novel interface in the anode can produce rapid Li⁺/Na⁺ storage kinetics and a long cycling performance.