2D Carbon Materials Research Articles

Recent Advances of Carbon Materials in Anodes for Aqueous Zinc Ion Batteries.

Carbon-based materials have been successfully applied in the zinc ion batteries to improve the energy storage capability and durability of zinc anodes. In this review, four types of carbon materials (conventional carbons, fiber-like carbons, carbon nanotubes, graphene and other 2D carbon materials) are introduced based on the electrode preparation, physicochemical property and battery performance. Several modification strategies are also illustrated, such as heteroatom doping, hierarchical design and metal/carbon composites. Besides the discussion of existing issues of zinc anodes, the structure-performance relationships are analyzed in depth. Finally, conclusive remarks of this review are summarized and prospects of the future improvement are proposed.

Hierarchical graphite oxide decorated UiO-66 for ultrahigh adsorption of dye with synergistic effect of ultrasonication: Experimental and density functional theory study

Indiscriminate disposal of azodyes demands the development of potential strategies for water treatment. Composites with tuned structural and functional properties, synthesized by amalgamation of 2D carbon materials with MOFs, emerges as a new generation adsorbents.Accordingly, our study focused on the synthesis of graphite oxide decorated UiO-66 MOF and its performance evaluation in ultrasonication assisted adsorptive removal of toxic Congo red dye from aqueous solution. The incorporation of GO tunes the microporous MOF to a hierarchical mesoporous/microporous structure. Theoretical analysis using density functional theory (DFT) was performed to predict the adsorption behaviour.The key finding which makes our study outstanding is the ultrahigh adsorption capacity (Qm − 1250 mg/g) of the synthesized composite, which is much higher than pure UiO-66, GO, and other reported adsorbents. The synergistic effect of the increased mesopore volume and availability of functional groups upon GO incorporation in the MOF improves the adsorption capacity. Adsorption occurs due to long-range intermolecular covalent and noncovalent interactions. The superior dye removal efficiency of the synthesized adsorbent along with good regeneration characteristics makes it a promising material for contaminants removal from aqueous solutions.

Highly active platinum single-atom catalyst grafted onto 3D carbon cloth support for the electrocatalytic hydrogen evolution reaction

Platinum single-atom catalysts (PtSACs) on 3D support are emerging as the new frontier in catalysis due to their atom-economy, outstanding performance, and the advantage to bridge the gap between homogeneous and heterogeneous catalysis. Here we report on a simple, single-step electrochemical grafting attachment of a metal-selective ligand, 2,6:2′,2″-terpyridine, and the synthesis of platinum single-atom electrocatalyst via metal uptake from aqueous salt solution. At an ultra-low loading of 0.26 ± 0.02 μg•cm−2 of platinum, the single-atom catalysts supported on porous 3D carbon cloth electrode via chemical bonding revealed higher mass activity ratios, up to 83.0 at η = 50 mV/RHE, compared to the commercial catalyst 20 % Pt/C. Using hydrogen binding energy as the descriptor for efficiency, density functional theory calculations show that promoting hydrogen evolution using terpyridine-Pt proceeds when the catalyst is in a 2+ charge state and with a single hydroxy co-ligand attached to Pt catalytic center. Calculations predict an HER overpotential of about 0.28 V. The electro-grafted terpyridine ligand proved to act as effective scavenger for leached platinum from the counter electrode during extended operational hours. The method to make the PtSAC is facile, non-hazardous and versatile without involving any elaborate pre- and/or post-treatment steps and, the cost of the added platinum to the ligand is only 0.1 US$ m−2.

Exfoliated Graphite: A Surface Renewed Electrode for Environmental Applications

Exfoliated graphite is a 2D carbon material that has recently received great attention owing to its remarkable analytical merits such as fast electron migration, ease of surface regeneration, high-temperature resistance, ability to withstand high-current density, excellent conductivity, and sensitivity. Due to its excellent analytical signature, an exfoliated graphite electrode has been reportedly used in the construction of sensors and biosensors for various applications. This electrode can be used alone or blended with several nanomaterials/semiconductors for the degradation of various organic pollutants in wastewater. Despite the outstanding results reported in the use of exfoliated graphite electrodes for various analytical applications, very few reports were documented in the literature. Therefore, this review elaborated on the importance of exfoliated graphite electrodes for electrochemical analysis.

Preparation of Hollow Niobium Oxide Nanospheres with Enhanced Catalytic Activity for Oxidative Desulfurization.

Hollow niobium oxide nanospheres were successfully synthesized by using prepared three-dimensional (3D) mesoporous carbon as the hard template. The 3D mesoporous carbon materials were prepared by using histidine as the carbon source and silica microspheres as the hard template. The samples were characterized by XRD, BET, SEM, TEM and other methods. The results show that the prepared niobium oxide nanospheres have a hollow spherical structure with an outer diameter of about 45 nm and possess a high specific surface area of 134.3 m2·g−1. Furthermore, the 3D mesoporous carbon materials have a typical porous structure with a high specific surface area of 893 m2·g−1. The hollow niobium oxide nanospheres exhibit high catalytic activity in oxidative desulfurization. Under optimal reaction conditions, the DBT conversion rate of the simulated oil is as high as 98.5%. Finally, a possible reaction mechanism is proposed.

Thermally induced hex-graphene transitions in 2D carbon crystals

Abstract Resourceful beyond-graphene two-dimensional (2D) carbon crystals have been proposed/synthesized; however, the fundamental knowledge of their melting thermodynamics remains lacking. Here, the structural and thermodynamic properties of nine contemporary 2D carbon crystals upon heating are investigated using first-principle-based ReaxFF molecular dynamics simulations. Those 2D carbon crystals show distinct evolution of energetic and Lindemann index that distinguish their thermal stabilities. There are two or three critical temperatures at which structural transformation occurs for non-hexagon-contained 2D carbon allotropes. Analysis of polygons reveals that non-hexagon-contained 2D carbon crystals show thermally induced hex-graphene transitions via mechanisms such as bond rotations, dissociation, and reformation of bonds. The study provides new insights into the thermodynamics and pyrolysis chemistry of 2D carbon materials, as well as structural transitions, which is of great importance in the synthesis and application of 2D materials in high-temperature processing and environment.

3D Microstructured Frequency Selective Surface Based on Carbonized Polyimide Films for Terahertz Applications

AbstractIn recent years, frequency selective surface (FSS)‐based two‐dimensional (2D) and three‐dimensional (3D) carbon materials such as carbon nanofibers, carbon nanotubes, and carbon‐filled filaments are essential tools to design millimeter‐wave radomes, absorbers, electromagnetic interference (EMI) shielding, and antenna reflectors in gigahertz (GHz) regimes. Terahertz (THz) technologies are gaining attentions from medical imaging to security surveillance. In this work, a 3D microstructured FSS using carbon‐based polyimide as a precursor to enhance the resonant frequency at the THz range. Furthermore, gold nanoparticles (AuNPs) are embedded on 3D microsturctured carbonized polyimide (3D‐CPI) film to improve their FSS property through plasmonic effects. From the time domain spectroscopy measurements, 3D‐CPI FSS film shows band‐stop filter properties in the frequency range of 0.5–1.5 THz and with a maximum return loss (RL) of 40.5 dB (at the resonant frequency of 1 THz). The 3D‐CPI/AuNPs film demonstrates the highest RL of 43.7 dB at the higher excitation resonance frequency ≈1.06 THz due to the interaction of plasmonic electrons with scattered delocalized electrons in carbon, which induces the mechanisms for EMI shielding. The results will open insight into 3D plasmonic carbon microstructures as an EMI shielding material at THz frequency.

Advances in multifunctional cementitious composites with conductive carbon nanomaterials for smart infrastructure

Conductive carbon nanomaterials have been extensively developed for smart cementitious composites to gain multifunctionalities (e.g. self-sensing, self-healing, self-heating, and electromagnetic interference shielding). This paper critically reviewed dispersion and percolation of 0 dimension (0D), 1 dimension (1D) and 2 dimensions (2D) carbon materials used in cementitious composites and their effects on the electrical and piezoresistive performances. The different dispersion methods summarized are from mechanical dispersion, ultrasonic and high shearing, chemical modification, mineral additives, to carbon materials at multiple dimensions and hybrid dispersion methods. The electrical resistivity and piezoresistivity of cementitious composites with single carbon material or hybrid carbon materials are comprehensively analysed and compared in terms of efficiency and self-sensing mechanism. Furthermore, the existing theoretical modelling studies have been reviewed, indicating that many factors related to the electrical and piezoresistive behaviours, such as water content and nanocomposite agglomeration, have not been considered yet. Although some previous studies demonstrated the potential of applying conductive cementitious composites for self-sensing or heating pavements, further explorations still should be conducted on sustainable and economical manufacturing. Subsequently, the challenges and perspectives of the self-sensing stability, data acquisition system and sensor configuration are proposed with potential solutions for future smart infrastructure.

Defect-rich and highly porous carbon nanosheets derived from Ti3AlC2 MAX with good lithium storage properties

Defect-rich, highly porous two-dimensional carbon nanosheets (CNS) have attracted tremendous research interests in catalysis and environmental purification and other fields, because of their unique micromorphology, chemical stability and high specific surface area. Herein, in this work, we report a new solution to synthesize an ultrathin two-dimensional CNS with rich defects and abundant pores via two-step etching the Ti3AlC2 with the help of I2 and NaOH. The CNS thickness, specific surface area and pore volume could be all tunable by adding the amount of I2. And the highest specific surface area and pore volume of the synthesized 2D CNS can be achieved 1134.4 m2/g and 0.80 cm3/g, with a thickness of only 0.64 nm and a yield of 35.9%. When employed as the anodes for lithium-ion batteries, the synthesized CNS anodes exhibit good cycling and rate capabilities. This work provides a novel and facile strategy for synthesizing highly porous and defective 2D carbon materials with good lithium storage properties.

Theoretical investigation of methane oxidation reaction over a novel metal-free catalyst biphenylene network

Since graphene was discovered in 2004, two-dimensional (2D) carbon materials have been investigated for many applications including as energy storage materials, gas sensors, and heterogeneous catalysts. Recently, a new type of carbon material, termed a biphenylene network has been successfully synthesized, and consists of four-, six- and eight-membered rings in its structure. In this work, we perform density functional theory (DFT) calculations to study the methane oxidation reaction on a pristine biphenylene network nanosheet to understand its catalytic property. We found that the four-membered ring of the biphenyl network nanosheet possesses much stronger catalytic activity for O2 decomposition and methane conversion to methanol than does the pristine graphene nanosheet. In addition, our results show that both methanol formation and formyl aldehyde formation mechanisms can occur on the biphenyl network nanosheet. Methanol formation is a kinetic reaction control process at 500 K, while the formyl aldehyde formation is the thermodynamic reaction control process at a higher temperature of 600 K. Thus, the operating temperatures will control the selectivity of methane oxidation reaction on the biphenyl network nanosheet. This finding shows that the pure carbon material biphenyl network nanosheet might be an excellent metal-free catalyst for methane oxidation reactions.

Fabrication of Co, N-Doping Hierarchical Porous Graphene from Metal Organic Framework for Oxygen Reduction Reaction in Microbial Fuel Cell

Graphene is a very attractive 2D carbon material, while the synthesis route of functional graphene is complex and complicated. The purpose of this study is to develop Co/N co-doped grapheme catalyst for ORR.Herein, a facile and universal pyrolysis method to explore the preparation of Co-N co-doped graphene through thermal exfoliation of 3D Co0.5Zn0.5-ZIF metal-organic framework by dimension reduction, and study the specific changes during process of dimensionality reduction, aiming at contributing to the transformation mode of 3D materials into 2D materials. The results showed that LiCl and KCl play different roles, namely the building carbon layer, pore-creating and exfoliation and acted simultaneously when they are added. A unique ultrathin 2D morphology of Co/N co-doped graphene, pores formed with the volatilization of zinc ions, and the appearance of abundant Co-N x active sites, which endow efficient catalytic activity of oxygen reduction reaction (ORR) in the alkaline electrolyte. Co/N-Go-Li/K-800 possesses the superior ORR activity among Co/N-Go-Li/K-T with an onset potential (0.15 V vs Ag/AgCl) and higher limiting current density(J@−0.8 V vs Ag/AgCl) (−5.20 mA·cm−2) closer to Pt/C (0.17 V vs Ag/AgCl and −5.86 mA·cm−2).

Optoelectronic Current through Unbiased Monolayer Amorphous Carbon Nanojunctions.

Monolayer amorphous carbon (MAC) is a recently synthesized disordered 2D carbon material. An ensemble of MAC nanofragments contains diverse manifestations of lattice disorder, and because of disorder the key unifying characteristic of this ensemble is poor electronic conductance. Curiously, our computational analysis of the electronic properties of MAC nanofragments revealed an additional commonality: a robust presence of charge-transfer character for electronic transitions from the occupied to virtual orbitals. This charge-transfer property suggests possible applications in optoelectronics. In this Letter, we demonstrate computationally that a laser pulse induces directional electronic currents in unbiased MAC nanojunctions and discuss the effects of pulse intensity on the magnitude of electron transfer.

Vibrational properties of graphdiynes as 2D carbon materials beyond graphene.

Two-dimensional (2D) hybrid sp–sp2 carbon systems are an appealing subject for science and technology. For these materials, topology and structure significantly affect electronic and vibrational properties. We investigate here by periodic density-functional theory (DFT) calculations the Raman and IR spectra of 2D carbon crystals belonging to the family of graphdiynes (GDYs) and having different structures and topologies. By joining DFT calculations with symmetry analysis, we assign the IR and Raman modes in the spectra of all the investigated systems. On this basis, we discuss how the modulation of the Raman and IR active bands depends on the different interactions between sp and sp2 domains. The symmetry-based classification allows identifying the marker bands sensitive to the different peculiar topologies. These results show the effectiveness of vibrational spectroscopy for the characterization of new nanostructures, deepening the knowledge of the subtle interactions that take place in these 2D materials.

P-Si/Macro-Assembled Graphene/n-Si Heterojunction Near-Infrared Photodetector

p-type silicon (p-Si)/macro-assembled graphene nanofilm (nMAG)/n-type silicon (n-Si) heterojunction is utilized to fabricate near-infrared photodetector. Dual built-in electric fields were established in the same direction at the p-Si/nMAG and nMAG/n-Si heterojunctions, providing an enhanced electron-hole separation ability. The p-Si/nMAG/n-Si device has realized responsivities of 90 mA/W and 45 mA/W under 900 nm and 1064 nm illumination at room temperature and corresponding external quantum efficiency (EQE) of 11.8% and 5.2%, respectively, which is 30% and 45% higher than that of the single-junction nMAG/n-Si device. In this work, we applied two-dimensional (2D) carbon materials combined with monocrystalline silicon to explore complementary metal-oxide-semiconductor (CMOS) process-compatible device fabrication techniques, which paves the way to develop low-cost and large-scale near-infrared carbon-based photodetectors.

The characterisation of commercial 2D carbons: graphene, graphene oxide and reduced graphene oxide

Commercial 2D carbon materials are shown to be largely nanographite with a small percentage of single layer material present.

Construction of a N,P doped 3D dendrite-free lithium metal anode by using silicon-containing lithium metal.

Lithium is thought to be an excellent anode material for next-generation Li metal batteries (LMBs). However, some problems with lithium anodes often lead to serious safety concerns and catastrophic failures due to the huge volume change, Li dendritic growth, and related side reactions. Therefore, in order to manufacture stable rechargeable batteries, the abovementioned serious problems must be effectively solved. In this paper, a three-dimensional N,P-doped silicon-containing lithium anode is designed and prepared by in situ metallurgy using low-cost Si3N4. The 3D stable composite anode (DLi/LiSix CA) was prepared by adding a small amount of Si3N4 to molten lithium to form N-doped silicon-containing lithium metal which was supported on a polyaniline modified carbon cloth (PMCC). The results show that the DLi/LiSix CA not only has high Li affinity but can also effectively inhibit lithium nucleation and lithium dendritic growth, so as to maintain good structural stability in the process of Li plating/stripping. The new lithium metal anode based on doping and 3D carbon cloth shows good cycling stability and low polarizability in both symmetrical and full cells.

Cobalt Nanoparticle Adorned on Boron- and Nitrogen-Doped 2d-Carbon Material for Sonogashira Cross-Coupling Reactions: Greener and Efficient Synthesis of Anti-Cancer Drug, Ponatinib

Cobalt Nanoparticle Adorned on Boron- and Nitrogen-Doped 2d-Carbon Material for Sonogashira Cross-Coupling Reactions: Greener and Efficient Synthesis of Anti-Cancer Drug, Ponatinib

Modulation of graphene and graphdiyne by metaln (n = 1–5) adsorption and nucleation and the effect on hydrogen evolution reaction

Comprehending the interaction of metal clusters with two-dimensional (2D) carbon materials at the atomic level is important for the rational design of relative materials for various applications. The geometrical and electronic modulation of graphene and graphdiyne (GDY) by the adsorption and nucleation of Cun, Irn, and Pdn (n = 1–5) and the effect on hydrogen evolution reaction (HER) were studied employing dispersion-corrected density functional theory methods. The bonding strength between the metal Mn (n = 1–5) clusters and the considered 2D materials generally followed the order of Irn-substrate > Pdn-substrate > Cun-substrate. The modified electronic properties induced by the metal decoration affected the H adsorption. According to the Sabatier’s principle, the Mn@graphene present better HER catalytic properties than the pristine graphene, while the Mn@GDY depends. Based on the calculated ΔG0(H) and H diffusion barrier, H can easily diffuse from the C site of graphene to the metal site and show better HER activities. The reverse H diffusion from the metal site to the carbon site of GDY for GDY supported Pd1, Pd5, and Ir5 could happen at room temperature, thereby improving the HER activity at pH = 0. A series of linear relationships are found, revealing the possible structure–activity relations.

Second harmonic generation from tetraphenylethylene functionalized graphdiyne

The nonlinear optical (NLO) properties of two-dimensional (2D) layered materials have received extensive attention for their promising application prospects in the field of optoelectronics. Among these materials, 2D carbon materials have been pushed to the research hotspot thanks to their unique chemical and electronic structures. However, the exploration of second harmonic generation is currently limited to sp2 hybridized 2D carbon materials, while the research on multi-hybridized carbon atomic materials is relatively rare. Here, we report the observation of optical second harmonic from tetraphenylethylene-graphdiyne (TPE-GDY), a fully conjugated fluorescent 2D material composed of sp and sp2 hybridized carbon atoms based on the TPE unit. TPE-GDY is mixed with polyvinylpyrrolidone (PVP) to prepare TPE-GDY/PVP nanocomposite films, which further improves the stability of TPE-GDY. Cotton effect and favorable SHG response have been observed from these composite films. Our research enriches the material system in the field of NLO effects and opens up broad prospects for functional and potential applications of 2D graphdiyne materials.

1D Nanowire Heterojunction Electrocatalysts of MnCo2O4/GDY for Efficient Overall Water Splitting

AbstractRational design and synthesis of non‐precious metal‐based electrocatalysts for efficient overall water splitting (OWS) in an integrated electrolyzer are of great significance for the development of hydrogen energy. To this end, nanowire‐structured heterogenous MnCo2O4/graphdiyne arrays are synthesized on the surface of 3D carbon cloth (NW‐MnCo2O4/GDY) by using in situ assembly and coupling strategy. Experiments demonstrated that the special core/shell‐nanowire structure and synergistic interaction between the MnCo2O4 and GDY can greatly improve the electric conductivity, facilitate the mass/ion transport and gas emissions, expose more active sites, and thus lead to the enhancement of the catalytic activity and long‐term stability of the electrocatalysts for OWS. For example, the alkaline water electrolyzer assembled by NW‐MnCo2O4/GDY shows high‐performance with only 1.47 and 1.60 V required to reach a current density of 10 and 100 mA cm−2, respectively, which is even better than that of previously reported electrocatalysts.