2D Nanomaterials Research Articles

Algorithm for Reproducible Analysis of Semiconducting 2D Nanomaterials Based on UV‐VIS Spectroscopy

AbstractRapid and reliable analysis of liquid dispersions of 2D materials is essential for fully harnessing their potential, allowing size and quality validation before subsequent processing or device fabrication. Existing UV‐VIS extinction spectroscopy‐based metrics, particularly those related to thickness, have shown promise but rely on manual data processing, which can introduce irreproducibility and user errors. To address this challenge and enable uniform analysis across laboratories, a freely available program is developed for the reproducible analysis of nanosheet dispersions. Specifically, a smoothing routine is applied to the spectral data, takes the second derivative, and use integral areas to find the wavelength of exciton transitions. This program enables rapid measurement of nanosheet concentration, length, and thickness by UV‐VIS spectroscopy and thickness metrics are refined for eight common 2D nanomaterials. The program and methodology are freely available for use and allow metrics for new materials to be implemented easily in the future.

Conjugated cobalt‐based metal complex nanosheet for fabricating high‐performance supercapacitor electrode

AbstractIn order to cope with the increasingly serious problem of energy shortage, supercapacitors have been developed as a clean and renewable energy source, and the supercapacitors with excellent energy density and long cycle life are imperative. Here, by employing a facile liquid–liquid (L‐L) interfacial method at room temperature (RT), a set of two‐dimensional (2D) metal complex nanosheets N1‐N3 have been synthesized by the facile coordination between Co2+ ion and 2,3,6,7,10,11‐hexaiminotriphenylene (HITP). Given the layered superstructure with well‐ordered nanopores, the N1‐N3 electrodes displayed excellent capacities of 4751.9, 5770.9 and 6075.2 F g−1 at 1 A g−1, and a good cyclic stability with 92.1% capacity retention after 1000 cycles for the N3 electrode. The asymmetric supercapacitor device with N3 as the positive electrode delivers a maximum energy density of 238.2 Wh kg−1 at a power density of 1610.1 W kg−1 and an excellent cycling stability with a capacitance retention of 109.1% after 5000 cycles. This is the best electroactive bottom‐up metal complex nanosheet reported so far for use in supercapacitor, which greatly expands the applicability of this 2D nanomaterial in energy device applications.image

Effect of morphology and structure of MXene Ti3C2Tx on mechanical, thermal properties of PEEK nanocomposite

As a new type of 2D nanomaterials, MXene can improve the thermal, mechanical, and tribological performance of polymers as a reinforcing additive. However, there is a lack of systematic research on the impact of the morphology and structure of MXene on the performance of nanocomposite. In this study, MXene Ti3C2Tx with different morphologies was prepared and the effect of morphologies on the mechanical, thermal and creep properties was explored. Mechanical test results illustrate that the addition of MXene Ti3C2Tx fillers contributes to the improvement of mechanical properties. Among the three fillers, d-Ti3C2Tx exhibit a better reinforcement effect in PEEK than m-Ti3C2Tx and f-Ti3C2Tx, which are greatly related to the morphology of the MXene Ti3C2Tx, the interface and defects between the PEEK and the MXene Ti3C2Tx. After adding MXene to the PEEK matrix, the internal friction of PEEK molecule segment motion would aggrandize and the composites would deform and take longer relaxation times. Due to the larger interface between d-Ti3C2Tx and the matrix, the composite material exhibits the smallest creep strain magnitude and permanent deformation behavior after recovery. However, the high activity of 2D MXene nanomaterials resulted in a decrease in the thermal stability of PEEK.

One-Dimensional and Two-Dimensional Nanomaterials for Sensor Applications

The significance of 1D and 2D nanomaterials in sensor technology lies in their unique properties and the potential for high-performance sensing [...]

Fabrication of two-dimensional FePS3 nanosheets for promising photo/electrocatalytic applications

Transition metal phosphorus trisulfides, namely sulfides composed of three elements, stand out within 2D nanomaterials due to the unique layered structure, distinctive bonding, and electronic configurations. However, the preparation of ultrathin nanosheets encounters significant challenges due to the inherent properties of the material itself and the complexity of the synthetic process. In this work, we successfully fabricated ultrathin FePS3 nanoflakes with lateral dimensions of 500–800 nm and an average thickness of 5 nm utilizing mechanically assisted liquid-phase exfoliation in N-Methyl-2-pyrrolidone solution. The unique few-layer structure of FePS3 may increase the number of active sites, facilitating the rapid separation and migration of photo-induced charge carriers. Consequently, this enhancement leads to an increase in photogenerated current and a substantial reduction in resistance. This study presents an effective approach for optimizing light absorption and charge separation processes of 2D nanostructure, thereby providing valuable insights for the rational design of efficient photocatalysts based on ultrathin FePS3 nanosheet as a co-catalyst.

Insights into the hierarchical geometries of hybrid low-dimensional carbons

Hybrid 3D nanomaterials have been prepared by immobilizing the acid-functionalized MWCNTs into the edge-functionalized/oxidized Few Layer Graphene (FLG) flakes to address the dispersion and exfoliation of FLG flakes. Both acid-functionalized MWCNTs and the edge-oxidized FLG flakes were prepared in the laboratory. The acid-functionalized MWCNTs were prepared via oxidative treatment using a mixture of nitric acid (HNO3) and sulphuric acid (H2SO4). Fenton’s reaction was utilized for the preparation of the edge-oxidized FLG flakes using graphite flakes as the starting material. After the functionalization, the presence of the oxygen-containing functional groups was confirmed using FTIR spectroscopy and XPS spectroscopy. The thermal stabilities of the nanomaterials were compared using TGA thermogram and the 3D nanomaterial was observed to be more stable than any other nanoparticles that were prepared and reported in this paper. The surface morphology was observed using the SEM and TEM, and the immobilized functionalized MWCNTs between the edge functionalized FLG flakes were observed. The XRD spectra of the nanoparticles were also compared and Raman analyses have been carried out.

Nanosheets adsorption and antiviral activity of Favipiravir drug against envelope proteins of yellow fever virus: DFT and molecular docking simulation study

Our previous research investigated the delivery of Favipiravir (FAV) drug through the encapsulation of FAV into 1D nanomaterials (NMs), AlN, BN, and carbon nanotubes, now we evaluated the possibility of using 2D NMs carbon nanosheets (GPNS), boron nitride nanosheets (BNNS), and aluminum nitride nanosheets (AlNNS) as drug delivery systems. The adsorption of FAV drug in its two tautomeric forms over the surfaces of these NSs is conducted. The adsorption energies are in the range of − 0.681 to − 2.469 eV. FAV binds to BNNS and GPNS through stacking interactions, while it chemisorbs to AlNNS. NCI and QTAIM analyses confirmed the dominance of vdW interactions. The recovery times over NSs were shorter than those inside NTs, and they indicated that NSs are better for drug release while NTs bind better and have larger adsorption energies. MD simulations revealed that FAV showed a good level of resistance to yellow fever virus (YFV) infections.

Exploring the interaction between graphyne and Purinethol: A DFT study of drug loading capacity

Within this piece of research, DFT calculations were undertaken in order to investigate the drug-loading performance of graphyne for Purinethol. In order to evaluate the possibility of using graphyne as a carrier, the energetic, geometrical and optimized attributes of graphyne, Purinethol, and the complex of graphyne and Purinethol were investigated. We investigated three sites, namely a, b and c, in the structures of Purinethol for its interaction with graphyne. The most suitable interaction was the one in which sulfur and nitrogen atoms were involved. Purinethol had an interaction with graphyne with the adhesion-energy of −1.87 eV in the gaseous phase. The non-covalent interaction analysis was performed to explore the interaction of graphyne with Purinethol. Based on the analysis results, the interaction forces of the complex of graphyne and Purinethol were weak. The HOMO-LUMO analysis and charge-decomposition analysis were performed to describe the charge transported from Purinethol to graphyne during the formation of graphyne and Purinethol. The results demonstrated the possibility of using graphyne as a suitable carrier for Purinethol. The theoretical results obtained within this work can inspire researchers to find novel 2D nanomaterials for drug delivery purposes.

Tailoring the ion storage of MXene by aramid nanofibers towards self-standing electrodes for flexible solid-state supercapacitors

Two-dimensional (2D) transition metal carbides and nitrides (MXenes) are a class of 2D nanomaterials that can offer excellent properties for high-performance supercapacitors. Nevertheless, irreversible restacking of MXene sheets decreases the interlayer spacing, which inhibits the ion intercalation between the MXene nanosheets and finally deteriorates the electrochemical performance of supercapacitors. Herein, aramid nanofibers (ANFs) are mixed with Ti3C2T x MXene to prepare MXene/ANFs composite films. The restacking of MXene sheets is inhibited by the electrostatic repulsion between ANFs and MXene. The ANFs act as intercalation agents to increase the interlayer spacing of the composite films, which can improve the ion storage ability of supercapacitors. Furthermore, the ANFs enhance the mechanical strength of the composite films due to the strong hydrogen bonding interaction and nanomechanical interlocking between ANFs and MXene, endowing the composite films with self-standing property. The resultant composite films are used as electrodes for flexible solid-state supercapacitors to achieve high specific capacitance (996.5 mF cm−2 at 5 mV s−1) and outstanding cycling stability. Thus, this work provides a potential strategy to regulate the properties of 2D nanomaterials, which may expand the application of them in energy storage, ionic separation, osmotic energy conversion and beyond.

Environment-friendly synthesis of Ti3C2TX MXene by etching and galvanic reactions for Al removal of Ti3AlC2 MAX

Although MXene is acknowledged as next generation two-dimensional (2D) nanomaterials, in general, MXene has been obtained by using hazardous and corrosive etching agents such as HF and HCl. Therefore, in the present study, we report on the environment-friendly synthesis of 2D Ti3C2TX MXene using weak acid H3PO4 as etchant. We compare the Al etching capacity of H3PO4 paired with various metal fluorides (LiF, ZnF2, CuF2) to in-situ form HF. Out of all metal fluoride candidates, CuF2 is the most effective in the etching of Ti3AlC2 MAX not only due to the reaction of F− with Al but also the galvanic replacement of Cu2+ with Al. As a result, Ti3AlC2 MAX is mostly etched using H3PO4/CuF2 within only 4 h reaction and is completely etched in 12 h reaction. After etching, the Cu intercalated between MXene layers is extracted using maleic acid forming a Cu-maleic acid complex to produce exfoliated 2D MXene nanosheets. The exfoliated MXene contains mainly −F, −O, –OH surface terminations and a small portion of −PO4, exhibiting the good aqueous dispersibility.

Probing the Size Effect of Graphene Oxide Nanosheets on Ice Crystal Regulation and Laser-Assisted Rapid Rewarming.

Two-dimensional (2D) nanomaterials have attracted many researchers to explore the effect of ice control and rapid deicing due to their functional groups, large specific surface area, and excellent photothermal properties. However, the impact of size effects on ice crystal formation, growth, and photothermal performance has been rarely explored. Here, graphene oxide nanosheets (GO NSs) with controllable sizes were used as a representative of 2D nanomaterials to probe the effect of size on ice crystal regulation and rapid rewarming in cell cryopreservation. All sizes of GO NSs exhibited notable inhibitory effects on ice crystal size during the recrystallization process. Significantly, when the size of GO NSs was smaller than a certain size (<150 nm), they showed a more significant ice recrystallization suppression effects, which could reduce the ice crystal size to about 17% of that of pure water. Meanwhile, the photothermal experiments also indicated that smaller-sized GO NSs exhibited better photothermal behavior, with 90 nm GO NSs (GO-90) heating to 70 °C in just 1 min induced by an 808 nm laser (2 W/cm2). Furthermore, applying GO-90 (200 μg/mL) to cell cryopreservation, cell viability could reach 95.2% and 93% with a low amount of traditional cryoprotectant (2% v/v DMSO) for A549 cells and HeLa cells after recovery, respectively. With the assistance of a 808 nm laser, the rewarming time was also shortened to 20 s, greatly improving the rewarming rate. Our work associated specific sizes of 2D nanomaterials with their ice growth inhibition behaviors during recrystallization and photothermal properties to synergistically improve cell cryopreservation efficiency, providing guidance for effectively designing novel 2D nanomaterials for collaborative control of ice crystals in cell cryopreservation.

Recent Advances in Non-Ti MXenes: Synthesis, Properties, and Novel Applications.

One of the most fascinating 2D nanomaterials (NMs) ever found is various members of MXene family. Among them, the titanium-based MXenes, with more than 70% of publication-related investigations, are comparatively well studied, producing fundamental foundation for the 2D MXene family members with flexible properties, familiar with a variety of advanced novel technological applications. Nonetheless, there are still more candidates among transitional metals (TMs) that can function as MXene NMs in ways that go well beyond those that are now recognized. Systematized details of the preparations, characteristics, limitations, significant discoveries, and uses of the novel M-based MXenes (M-MXenes), where M stands for non-Ti TMs (M=Sc, V, Cr, Y, Zr, Nb, Mo, Hf, Ta, W, and Lu), are given. The exceptional qualities of the 2D non-Ti MXene outperform standard Ti-MXene in several applications. There is many advancement in top-down as well as bottom-up production of MXenes family members, which allows for exact control of the M-characteristics MXene NMs to contain cutting-edge applications. This study offers a systematic evaluation of existing research, covering everything in producing complex M-MXenes from primary limitations to the characterization and selection of their applications in accordance with their novel features. The development of double metal combinations, extension of additional metal candidates beyond group-(III-VI)B family, and subsequent development of the 2D TM carbide/TMs nitride/TM carbonitrides to 2D metal boride family are also included in this overview. The possibilities and further recommendations for the way of non-Ti MXene NMs are in the synthesis of NMs will discuss in detail in this critical evaluation.

Interfacial Super‐Assembly of Vacancy Engineered Ultrathin‐Nanosheets Toward Nanochannels for Smart Ion Transport and Salinity Gradient Power Conversion

AbstractIon‐selective nanochannel membranes assembled from two‐dimensional (2D) nanosheets hold immense promise for power conversion using salinity gradient. However, they face challenges stemming from insufficient surface charge density, which impairs both permselectivity and durability. Herein, we present a novel vacancy‐engineered, oxygen‐deficient NiCo layered double hydroxide (NiCoLDH)/cellulose nanofibers‐wrapped carbon nanotubes (VOLDH/CNF‐CNT) composite membrane. This membrane, featuring abundant angstrom‐scale, cation‐selective nanochannels, is designed and fabricated through a synergistic combination of vacancy engineering and interfacial super‐assembly. The composite membrane shows interlayer free‐spacing of ~3.62 Å, which validates the membrane size exclusion selectivity. This strategy, validated by DFT calculations and experimental data, improves hydrophilicity and surface charge density, leading to the strong interaction with K+ ions to benefit the low ion transport resistance and exceptional charge selectivity. When employed in an artificial river water|seawater salinity gradient power generator, it delivers a high‐power density of 5.35 W/m2 with long‐term durability (20,000s), which is almost 400 % higher than that of the pristine NiCoLDH membrane. Furthermore, it displays both pH‐ and temperature‐sensitive ion transport behavior, offering additional opportunities for optimization. This work establishes a basis for high‐performance salinity gradient power conversion and underscores the potential of vacancy engineering and super‐assembly in customizing 2D nanomaterials for diverse advanced nanofluidic energy devices.

Interfacial Super-Assembly of Vacancy Engineered Ultrathin-Nanosheets Toward Nanochannels for Smart Ion Transport and Salinity Gradient Power Conversion.

Ion-selective nanochannel membranes assembled from two-dimensional (2D) nanosheets hold immense promise for power conversion using salinity gradient. However, they face challenges stemming from insufficient surface charge density, which impairs both permselectivity and durability. Herein, we present a novel vacancy-engineered, oxygen-deficient NiCo layered double hydroxide (NiCoLDH)/cellulose nanofibers-wrapped carbon nanotubes (VOLDH/CNF-CNT) composite membrane. This membrane, featuring abundant angstrom-scale, cation-selective nanochannels, is designed and fabricated through a synergistic combination of vacancy engineering and interfacial super-assembly. The composite membrane shows interlayer free-spacing of ~3.62 Å, which validates the membrane size exclusion selectivity. This strategy, validated by DFT calculations and experimental data, improves hydrophilicity and surface charge density, leading to the strong interaction with K+ ions to benefit the low ion transport resistance and exceptional charge selectivity. When employed in an artificial river water|seawater salinity gradient power generator, it delivers a high-power density of 5.35 W/m2 with long-term durability (20,000s), which is almost 400 % higher than that of the pristine NiCoLDH membrane. Furthermore, it displays both pH- and temperature-sensitive ion transport behavior, offering additional opportunities for optimization. This work establishes a basis for high-performance salinity gradient power conversion and underscores the potential of vacancy engineering and super-assembly in customizing 2D nanomaterials for diverse advanced nanofluidic energy devices.

Emerging 2D Nanomaterials-Integrated Hydrogels: Advancements in Designing Theragenerative Materials for Bone Regeneration and Disease Therapy.

This review highlights recent advancements in the synthesis, processing, properties, and applications of 2D-material integrated hydrogels, with a focus on their performance in bone-related applications. Various synthesis methods and types of 2D nanomaterials, including graphene, graphene oxide, transition metal dichalcogenides, black phosphorus, and MXene are discussed, along with strategies for their incorporation into hydrogel matrices. These composite hydrogels exhibit tunable mechanical properties, high surface area, strong near-infrared (NIR) photon absorption and controlled release capabilities, making them suitable for a range of regeneration and therapeutic applications. In cancer therapy, 2D-material-based hydrogels show promise for photothermal and photodynamic therapies, and drug delivery (chemotherapy). The photothermal properties of these materials enable selective tumor ablation upon NIR irradiation, while their high drug-loading capacity facilitates targeted and controlled release of chemotherapeutic agents. Additionally, 2D-materials -infused hydrogels exhibit potent antibacterial activity, making them effective against multidrug-resistant infections and disruption of biofilm generated on implant surface. Moreover, their synergistic therapy approach combines multiple treatment modalities such as photothermal, chemo, and immunotherapy to enhance therapeutic outcomes. In bio-imaging, these materials serve as versatile contrast agents and imaging probes, enabling their real-time monitoring during tumor imaging. Furthermore, in bone regeneration, most 2D-materials incorporated hydrogels promote osteogenesis and tissue regeneration, offering potential solutions for bone defects repair. Overall, the integration of 2D materials into hydrogels presents a promising platform for developing multifunctional theragenerative biomaterials.

Rapid fluorescent nucleic acid sensing with ultra-thin gold nanosheets

Fluorescently labeled DNA oligonucleotides and gold nanospheres have been frequently utilized in biosensors, providing efficient nucleic acid detection. Nevertheless, the restricted loading capacity of gold nanospheres undermines overall sensitivity. In this study, we employed four-atom-thick ultrathin gold nanosheets (AuNSs), utilizing a “pre-mix model” for rapid target nucleic acid detection. In this approach, fluorescently labeled DNA probes were pre-incubated with the target nucleic acid, followed by the addition of AuNSs for probe adsorption and fluorescence quenching. With the developed method, we efficiently and rapidly detected the SARS-CoV-2 N gene sequence within 30 min, involving a brief 15-min target pre-incubation and a subsequent 15-min adsorption of free probes and fluorescence quenching by AuNSs. This method exhibited heightened sensitivity compared to gold nanospheres, boasting a limit of detection (LOD) of 0.808 nM. Furthermore, exceptional recovery was achieved in simulated biological samples. The study introduces an effective strategy for nucleic acid sensing characterized by rapidity, heightened sensitivity, ease of operation, and robustness. These findings encourage further development of rapid biomarker sensing methods employing 2D nanomaterials.

Role of covalent crosslinking and 2D nanomaterials in the fabrication of advanced organic solvent nanofiltration membranes: A review of fabrication strategies, recent advances, and challenges

Organic solvent nanofiltration (OSN) membranes have gained significant attention owing to their pivotal role in various industrial applications, including pharmaceuticals, fine chemicals, and manufacturing. This review provides a comprehensive overview of the recent advances in OSN membrane technology, focusing on membrane materials, fabrication techniques, and strategies for tuning the chemistry, structure, and performance of OSN membranes. Initially, the fundamental principles underlying OSN are described, highlighting the critical parameters influencing membrane selectivity, permeability, and stability in organic solvents. It also focuses on the importance of covalent crosslinking in the design and fabrication of dense polyamide membranes. Subsequently, the design and synthesis of novel membrane materials are discussed, including polymeric, inorganic, and hybrid membranes. The use of 2D nanomaterials is summarized, with an emphasis on their structural characteristics and tailored properties for solvent separation applications. We further explored the innovative fabrication strategies, such as interfacial polymerization, modification of ultrafiltration supports, and tuning of the active layer chemistry by incorporating the membrane structure with porous nanofillers. This review also discusses the inhomogeneity issues between inorganic nanofillers and organic matrices of membranes as well as the strategies to overcome these limitations through proper functionalization. Finally, we identified emerging trends and prospects in OSN membrane research, encompassing sustainability, scalability, and integration with other membrane processes, to address existing challenges and discover new opportunities for efficient solvent separation in diverse industrial sectors.

Composite 2D Material-Based Pervaporation Membranes for Liquid Separation: A Review.

Today, chemistry and nanotechnology cover molecular separations in liquid and gas states by aiding in the design of new nano-sized materials. In this regard, the synthesis and application of two-dimensional (2D) nanomaterials are current fields of research in which structurally defined 2D materials are being used in membrane separation either in self-standing membranes or composites with polymer phases. For instance, pervaporation (PV), as a highly selective technology for liquid separation, benefits from using 2D materials to selectively transport water or other solvent molecules. Therefore, this review paper offers an interesting update in revising the ongoing progress of PV membranes using 2D materials in several applications, including solvent purification (the removal of water from organic systems), organics removal (the removal of organic molecules diluted in water systems), and desalination (selective water transport from seawater). In general, recent reports from the past 3 years have been discussed and analyzed. Attention has been devoted to the proposed strategies and fabrication of membranes for the inclusion of 2D materials into polymer phases. Finally, the future trends and current research gaps are declared for the scientists in the field.

Nanofiber-Reinforced MXene/rGO Composite Aerogel for a High-Performance Piezoresistive Sensor and an All-Solid-State Supercapacitor Electrode Material.

The assembly of two-dimensional (2D) nanomaterials into a three-dimensional (3D) aerogel can effectively prevent the problem of restacking. Here, nanofiber-reinforced MXene/reduced graphene oxide (rGO) conductive aerogel is prepared via the hydrothermal reduction of GO using pyrrole and in situ composite with MXene. Combined with low-content 2D conductive nanosheets (MXene and rGO) as "brick", conductive polypyrrole as "mortar", and one-dimensional (1D) nanofiber as "rebar", a strong interfacial cross-linking of MXene and rGO nanosheets is realized through covalent and noncovalent bonds to synergistically improve its mechanical performance. Based on the prepared MXene/rGO aerogel, a high-performance piezoresistive sensor with a sensitivity of up to 20.80 kPa-1 in a wide pressure range of 15.6 kPa is obtained, and it can withstand more than 5000 cyclic compressions. Besides, the sensor shows a stable output and can be applied to monitor various human motion signals. In addition, an all-solid-state supercapacitor electrode is also fabricated, which shows a high area-specific capacitance of up to 274 mF/cm2 at a current density of 1 mA/cm2.

Covalently modified MoS2 for the fabrication of interlayered thin film composite membranes with excellent structural stability against swelling and drying in organic solvent nanofiltration

Thin film nanocomposite (TFNi) membranes interlayered with 2D nanomaterials are promising for organic solvent nanofiltration (OSN) applications. However, swelling and drying problems can arise due to the instability of the 2D nanomaterial interlayer in different solvents and humidity conditions. To address this issue, covalently modified molybdenum disulfide (MoS2) nanosheets (MoS2–COOH and MoS2–CONH2) were used as interlayers in the fabrication of TFNi membranes. The covalent groups acted as spacers to stabilize the interlayer spacing of the MoS2 interlayer and regulate its structural stability in diverse solvents and drying conditions. The TFNi membranes interlayered with MoS2–COOH and MoS2–CONH2 nanosheets demonstrated excellent structural stability and maintained their high permeance even after exposure to various solvents and drying conditions. The TFNi-MoS2-CONH2 membrane exhibited the highest permeance of 8.60 ± 0.23 L m−2 h−1 bar−1 for MeOH, with a high rejection of 87.1 ± 1.3 % for Evans Blue (EB). Furthermore, the TFNi membranes exhibited sustained separation performance throughout the 72 h test, demonstrating their structural stability. This study highlights the potential of TFNi membranes interlayered with covalently modified MoS2 nanosheets for OSN applications, providing high permeance and structural stability in diverse solvents and drying conditions.