Ti3C2 MXene Research Articles

Self-assembled sensing interface based on specific aptamer functionalized Ti3C2 MXene for ultrasensitive antibiotic detection in milk

A self-assembled sensing interface based on Ti3C2 MXene functionalized by aptamer had been successfully constructed in this work, which fully utilizes the electrical properties of Ti3C2 MXene and the specific recognition ability of the aptamer. Subsequently, we studied the performance of the sensing interface using two antibiotic residues as examples. Under the optimal conditions, the sensing interface showed a linear range of 100 fM–1 μM and a limit of detection of 1 fM to detect kanamycin and tetracycline, furthermore the recovery rates were 97.15%–103.00% and 99.559%–106.36%, respectively. In addition, the sensing behaviors of aptamers specific recognition of target can be perceived by the interface, thereby exhibiting different electrical responses. Therefore, the self-assembled sensing interface not only provided a new avenue for the development of ultrasensitive technology in the food analysis field but also for investigating aptamer configurational transformations.

All in one doubly pillared MXene membrane for excellent oil/water separation, pollutant removal, and anti-fouling performance

Given the diversity and complexity of coexisting oil/dyes/heavy metal ions/microorganisms in wastewater and volatile organic compounds (VOCs) in the air, developing separation materials featured in higher separation efficiency and lower energy consumption for oil and water separation, pollutant removal, and anti-fouling is urgently needed, but it remains a major challenge till now. Herein, a multifunctional Ti3C2 MXene membrane with unique double pillar support was proposed by liquid phase ultrasonication and vacuum filtration to overcome the above challenge. Introducing cetyl-trimethyl ammonium bromide (CTAB) and calcium chloride/sodium alginate (CaCl2/SA) to the MXene membrane as crossed double pillars and superhydrophilic surface increases the tolerance and wettability of the membrane. The fabricated doubly pillared MXene (d-Ti3C2) membrane exhibits superior oil/water (O/W) separation efficiency (99.76%) with flux (1.284 L m−2 h−1) for canola oil and organic dye removing efficiency for methyl blue (MB) 99.85%, malachite green (MG) 100%, and methyl violet (MV) 99.72%, respectively, which is 1.05, 1.44, 1.22, and 1.28 fold compared with pre-pillared Ti3C2 (p-Ti3C2). The superior anti-oil/dye/fouling is attributed to lower oil conglutination, high hydrophily, and antibacterial activity. The versatile MXene membrane also shows distinguished separation of VOCs (η > 99%) from polluted air. The experimental and molecular dynamics (MD) computational simulation results illustrate that the superior separation efficiency of the Ti3C2 MXene membrane is ascribed to the unique doubly pillared space channel. This study paves a new road to further research on one step integration strategy for complex O/W separation, wastewater and VOCs removal, and anti-fouling via tuning nano/macro architecture.

Ti3C2 MXene flakes assisted Mn0.5Cd0.5S/Ti3C2 MXene/g-C3N4 Z-scheme heterojunction for enhancing photocatalytic hydrogen evolution

Efficient carrier separation and high electron migration efficiency are essential for sustainable H2 energy production via photocatalysis. In this work, a Mn0.5Cd0.5S/Ti3C2 MXene/g-C3N4 all-solid-state Z-scheme photocatalyst is constructed by a series of processes, including low temperature calcination, etching, ultrasonication and solvothermal process. The appropriate energy band structures of g-C3N4 and Mn0.5Cd0.5S enable the formation of the Z-scheme system, achieving efficient carrier separation. The Ti3C2 MXene flakes assembled between g-C3N4 nanosheets and Mn0.5Cd0.5S particles can accelerate the charge migration rate in the system. The optimized ternary composite exhibits the highest hydrogen evolution rate (HER) of 13.7 mmol g−1 h−1, which is much higher than that of the pure g-C3N4 and Mn0.5Cd0.5S. Meanwhile, the apparent quantum yield (AQY) value of the composite at 420 nm reaches up to 24.07 % and exhibits high stability. Based on the characterization, the photocatalytic mechanism of carrier transfer in the Z-scheme heterojunction is also revealed. The finding of this article provides insights into the high efficiency of carrier transfer and separation in the photocatalytic reactions.

Synchronization of Ti3C2 MXene/Fe3+ with sodium persulfate for the degradation of reactive dyes

Rapid activation of sodium persulfate (SPS) for the degradation of C.I. Reactive Red 218 (RR218) was achieved using Ti3C2 MXene reduction of trace Fe3+. The degradation rate of RR218 reached 97.7% using a mixture containing 3 g L−1 of SPS, 3.35 mg L−1 of Fe3+ and 60 mg L−1 of MXene stirred at 25 °C for 30 min. The intense reduction of Ti3C2 MXene triggers the Fe3+/Fe2+ cycle thereby accelerating the activation of SPS. When reactive dyes were degraded by Fe3+/SPS/MXene process, ·OH played a major role. The dye degradation capacity of the Fe3+/SPS/MXene process decreased after 5 cycles of recycling. In addition, the wastewater treated under these conditions resulted in high dyeing efficiencies in reuse experiments. This study not only improves the understanding of the catalytic reaction of MXene but also provides a wastewater treatment and reuse process with low metal consumption and high efficiency.

Water desalination across nanoporous Ti3C2 MXene

Nanostructured materials have a modest thickness, which is comparable in scale to the chemical substances to be separated making them highly efficient in membrane-based separation applications. We performed a molecular dynamics simulation to investigate the effect of the functionalization of the nanoporous Ti3C2 MXene membrane on desalination efficiency. Hydrogenated (–H) and hydroxylated (–OH) pores are the two configurations that we looked at. The calculated water permeability, in the case of hydroxylated (–OH) groups linked to carbon atoms, is equal to 100 L.m−2.h−1.bar−1, and the salt rejection is equal to 100 %.

Porphyrin-functionalized glutathione-Ti3C2 MXene quantum dots for enhanced electrochemiluminescence and sensitive detection of copper ions

Ti3C2 MXene quantum dots (MQDs) have recently gained considerable attention as promising emerging nanomaterials for biosensing applications. However, it is still in the infancy of research on the functionalisation of MQDs to improve their properties. This work synthesised glutathione (GSH)-modified MQDs by hydrothermal method and functionalised them with porphyrin (TMPyP4), resulting in porphyrin-functionalised GSH-Ti3C2 MXene quantum dots (MQDs-TMPyP4) nanocomposite with enhanced electrochemiluminescence (ECL) properties. The lack of selectivity of MQDs and the weak luminescence intensity of ECL have been solved, expanding the method for developing materials with enhanced ECL properties. Cu2+ was found to quench the ECL luminescence of MQDs-TMPyP4, which is valuable for detecting copper ions. Consequently, we constructed a sensitive “Signal on–off” biosensor for Cu2+ detection. The biosensor demonstrated a sensitive response to copper ions within the concentration range of 10 nM to 10 μM, with an impressively low detection limit of 3.22 nM. Additionally, the biosensor exhibited good stability and selectivity. The ECL biosensor performed well and provided an efficient and ultra-sensitive method for detecting Cu2+.

A metal-organic framework and quantum dot-based ratiometric fluorescent probe for the detection of formaldehyde in food.

Agreen and sensitive ratio fluorescence strategy was proposed for the detection of formaldehyde (FA) in food based on a kind of metal-organic frameworks (MOFs), MIL-53(Fe)-NO2, and nitrogen-doped Ti3C2 MXene quantum dots (N-Ti3C2 MQDs) with a blue fluorescence at 450nm. As a type of MOFs with oxidase-like activity, MIL-53(Fe)-NO2 can catalyze o-phenylenediamine (OPD) into yellow fluorescent product 2,3-diaminophenazine (DAP) with a fluorescent emission at 560nm. DAP has the ability to suppress the blue light of N-Ti3C2 MQDs due to inner filter effect (IFE). Nevertheless, Schiff base reaction can occur between FA and OPD, inhibiting DAP production. This results in a weakening of the IFE which reverses the original fluorescence color and intensity of DAP and N-Ti3C2 MQDs. So, the ratio of fluorescence intensity detected at respective 450nm and 560nm was designed as the readout signal to detect FA in food. The linear range of FA detection was 1-200µM, with a limit of detection of 0.49µM. The method developedwas successfully used to detect FA in food with satisfactory results. It indicates that MIL-53(Fe)-NO2, OPD, and N-Ti3C2 MQDs (MON) system constructed by integrating the mimics enzyme, enzyme substrate, and fluorescent quantum dots has potential application for FA detection in practical samples.

Tailoring the morphology and charge transfer pathways of ultrathin Cd0.8Zn0.2S nanosheets via ionic liquid-modified Ti3C2 MXenes towards remarkable photocatalytic hydrogen evolution

Small-sized CdxZn1–xS solid solution nanomaterial is an important candidate for efficient photocatalytic hydrogen evolution (PHE), but it still suffers from easy agglomeration, severe photo corrosion, and fast photogenerated electron-hole recombination. To tackle these issues, herein, we propose a new strategy to modify CdxZn1–xS nanoreactors by the simultaneous utilization of ionic-liquid)-assisted morphology engineering and MXene-incorporating method. That is, we designed and synthesized a novel hierarchical Cd0.8Zn0.2S/Ti3C2 Schottky junction composite through the in-situ deposition of ultrathin Cd0.8Zn0.2S nanosheets on unique IL-modified Ti3C2 MXenes by a one-pot solvothermal method for efficiently PHE. The unique construction strategy tailors the thickness of ultrathin Cd0.8Zn0.2S nanosheets and prevents them from stacking and agglomeration, and especially, optimizes their charge transfer pathways during the photocatalytic process. Compared with pristine Cd0.8Zn0.2S nanosheets, Cd0.8Zn0.2S/Ti3C2 has abundant photogenerated electrons available on the Ti3C2 surface for proton reduction reaction, owing to the absence of deep-trapped electrons, suppression of electron-hole recombination in Cd0.8Zn0.2S and high-efficiency charge separation at the Cd0.8Zn0.2S/Ti3C2 Schottky junction interface. Moreover, the hydrophilicity, electrical conductivity, visible-light absorption capacity, and surficial hydrogen desorption of Cd0.8Zn0.2S/Ti3C2 heterostructure are significantly improved. As a result, the heterostructure exhibits outstanding photocatalytic stability and super high apparent quantum efficiency, being rendered as one of the best noble-metal-free Cd-Zn-S-based photocatalysts. This work illustrates the mechanisms of morphology control and heterojunction construction in controlling the catalytic behavior of photocatalysts and highlights the great potential of the IL-assisted route in the synthesis of high-performance MXene-based heterostructures for photocatalytic hydrogen evolution.

Construction of 2D/2D BCNS/Ti3C2 heterojunction with boron-doped g-C3N4 and Ti3C2 MXene for enhanced photocatalytic water splitting

Graphitic carbon nitride (g-C3N4) has attracted great interest in photocatalytic water splitting. However, the poor photogenerated charge carriers transfer and the insufficient driving force for oxygen evolution reaction limit its practical application. In this work, boron-doped g-C3N4 nanosheets (BCNS) have been synthesized by calcining a mixture of g-C3N4 and NaBH4. The synthesized BCNS were then combined with Ti3C2 MXene using electrostatic self-assembly to construct a 2D/2D BCNS/Ti3C2 heterojunction. The resultant BCNS retained the original framework of g-C3N4, while the optimized band structure of BCNS induced prominently enhanced visible light absorption, accelerated charge carriers separation, and the increased driving force for water oxidation compared to pure g-C3N4. Density functional theory further proved that BCNS can enhance the driving force for photocatalytic O2 evolution. Moreover, the construction of 2D/2D face-to-face BCNS/Ti3C2 heterojunction was carried out to further enhance photocatalytic performance due to the intimate contact interface and the accelerated separation and transfer of photogenerated charge carriers. As a result, the 2D/2D BCNS/Ti3C2 hetrojunction exhibited a dramatically improved photocatalytic water-splitting performance compared to pristine g-C3N4. This integrated engineering strategy, involving non-metal element doping and 2D/2D heterojunction construction, might provide a unique paradigm for the rational design of efficient photocatalysts for photocatalytic water splitting.

Ultrasensitive refractive index sensing of optical microfiber couplers coated with Ti3C2 MXene

Two-dimensional (2D) MXene has recently been found to play a significant role in constructing biosensing platforms due to its excellent biocompatibility, large specific surface area, and broad optical absorption. In this article, an ultra-sensitive refractive index (RI) sensor based on an optical microfiber coupler (OMC) coated with Ti3C2 MXene is proposed and experimentally demonstrated. Numerical results reveal that surface modification of MXene enhances the RI sensitivity of OMC and creates a new artificial dispersion turning point (ADTP). The OMC with a dispersion turning point (DTP) at 1300 nm is fabricated using a hybrid fusion elongation-wet etching method. It has a waist width of approximately 2.46 µm. We experimentally achieved the RI sensitivity of 9.1 × 104 ± 0.42 × 104 nm/RIU using the OMC. MXene improves the sensitivity of the OMC because Ti3C2 MXene can change the effective refractive index (ERI) for both the even and odd modes, leading to the interference dips shifting closer to the DTP. The experimental results demonstrate that the RI sensitivity of the OMC coated with Ti3C2 MXene can reach -1.7 × 105 ± 0.2 × 105 nm/RIU, which shows a ∼87% sensitivity boost compared with bare OMC. The proposed sensor is expected to be used for high-sensitivity biochemical molecule detection.

Defect-enriched BiOIO3/Ti3C2 MXene 2D/2D Schottky-type heterostructure for efficient and selective CH4 production via CO2 photoreduction: Unveiling the roles of defect inclusion and Ti3C2 MXene co-catalyst

The photoreduction of CO2 using solar energy to produce energy-efficient fuels is a sustainable technology that addresses energy needs while reducing carbon emissions. However, synthesizing efficient and robust photocatalysts for this process is challenging. This study introduces a viable approach for highly selective CO2 photoreduction to CH4 production by integrating defect-enriched BiOIO3 (DEBI) with a Ti3C2 (TC) MXene co-catalyst, forming an efficient 2D/2D Schottky-type heterostructure. The DEBI, enhanced with precise defect engineering, showed improved light absorption and charge separation efficiency. In tandem, the TC MXene co-catalyst facilitated rapid electron transfer and significantly minimized charge recombination. Consequently, the DEBI/TC-2 heterostructure, with an optimal 2 wt% TC MXene loading, achieved a CH4 yield of 52.8 μmol h−1 g−1, representing a remarkable 20.5- and 6.3-fold increase over pristine BiOIO3 and DEBI, respectively. The Schottky-type 2D/2D heterostructure also demonstrated an impressive apparent quantum yield of 0.72%, 99% CH4 selectivity over H2 generation, and remarkable stability across multiple cycles. This study underscores the synergistic advantages of defect engineering and MXene co-catalyst integration in a single system, proposing a novel direction for designing highly efficient photocatalysts for solar-driven CO2 reduction in energy-efficient fuel production.

Harnessing Photo‐to‐Thermal Conversion in Sulfur‐Vulcanized Mxene for High‐Efficiency Solar‐to‐Carbon‐Fuel Synthesis

AbstractHarnessing solar energy for the conversion of CO2 into value‐added chemicals and fuels represents a promising strategy for sustainable development. Photo‐to‐thermal (PTT) conversion, an often‐underestimated factor, offers a remarkable approach to enhance the photocatalytic transformation of CO2, by reducing the activation energy of catalytic reactions and accelerating reaction kinetics. In order to achieve a higher energy return on investment (EROI), in this study, a sulfur‐vulcanized, multi‐layer Ti3C2 MXene is unveiled, capable of efficient sunlight‐driven CO2 photoreduction, by capitalizing on PTT conversion across the full visible‐to‐near‐infrared (NIR) spectrum. The vulcanization strategy is pivotal here, as it not only introduces an abundance of reactive sites but also extends the NIR response (peaking at 1095 nm) of MXene. The resulting rapid PTT and synergistic photo‐thermal‐catalytic CO2 reduction constitute a significant advance in this area, where CH4 (12.03 mmol g−1 h−1) and C2H4 (3.55 mmol g−1 h−1) yields are achieved with a C2+ selectivity of 29.76% under concentrated natural sunlight. This work sets a new benchmark for EROI with an average solar‐to‐carbon‐fuel (STF) conversion efficiency greater than 0.045%.

Functionalized Ti3C2 MXene nanoporous as a reverse osmosis membrane: Insights from the atomistic level

Two-dimensional materials are highly efficient in membrane-based separation applications because of their small thickness, which is generally of the same order of magnitude as that of the chemical compounds to be separated. MXenes show an important efficiency in the desalination process, and functionalized Ti3C2 pores have not yet been investigated. We performed a molecular dynamics simulation to analyze the effect of pore area and chemical functionalization of the Ti3C2 MXene membrane on reverse osmosis desalination performance. We studied two configurations: hydrogenated (-H) pores and hydroxylated (-OH) pores. Our findings suggest the hydrophobic group (H) pores have the highest water permeability, and the hydrophilic group (OH) has an important salt rejection. The molecular dynamics results show that nanoporous Ti3C2 with an area equal to 100 Ų and a hydrogenated group linked to a carbon atom has the highest water permeability compared to other nanoporous Ti3C2 investigated with a salt rejection of more than 95 % for low pressure. In addition, the nanoporous Ti3C2 MXene membrane can be useful in the process of water desalination.

Comparing mechanism response and thermal conductivity of Ti3C2 and Ti3C2O2

This study uses molecular dynamics to investigate the effect of various temperatures and sample sizes on the mechanical mechanism and thermal conductivity of Ti3C2 and Ti3C2O2 Mxenes. The size of the Mxenes decides the severity of the crack and the von Mises stress clustering. The elastic phase trend of Ti3C2 materials in different sizes follows Hooke’s law, while the complex elastic trend is for the Ti3C2O2 models. The material toughness of Ti3C2 is relatively high, and the material’s response to the force is relatively stable and linear during the process of being subjected to pressure. The Ti3C2O2 Mxene presents a low toughness, low stability, and easier breakage during stress due to the complex structure and the formation of anatase and rutile TiO2 phases. The thermal conductivity decreases when the temperature increases or the material sizes decrease for both materials. Notably, Ti3C2 shows superior thermal conductivity in comparison to the Ti3C2O2 Mxene.

Enhanced photocatalytic performance of MXene-Modified cation-exchanged CoFe-LDH/CoFeCrO4 heterostructure for Antibiotic degradation and hydrogen production through synergistic charge dynamics

Systemizing an effective charge-transfer channel across a junction interface replete with ample active sites for enhancing the photocatalytic activity of semiconducting materials presents a formidable challenge. Here, we present a novel approach based on an in situ hydrothermal method for synthesizing CoFe-Layered Double Hydroxide (LDH)/CoFeCrO4 heterojunction materials that were partially derived from CoFe-LDH. These materials synergistically interact with Ti3C2 MXene nanosheets facilitating multi-interface interactions. Indeed, the highest tetracycline hydrochloride degradation rate of nearly 92% in 2 h was achieved because of the intense synergy between the CoFe-LDH/CoFeCrO4 heterojunction material optimized with 7.5 wt% of MXene nanosheets (CMC-7.5). This degradation performance was 3.1 times greater than that of the original CoFe-LDH. Further, CMC-7.5 produces the highest H2 gas of 458.79 μmol h−1g−1 from a photocatalytic water splitting reaction. The formation of a Schottky energy barrier between the partially derived CoFe-LDH/CoFeCrO4 unit and MXene promoted the fast transfer of photogenerated electrons from CoFe-LDH/CoFeCrO4 to the surface of MXene, thereby providing a plethora of active sites for photocatalytic reactions. Photoelectrochemical assessments using transient and linear sweep voltammetry along with electrochemical impedance spectroscopy confirmed efficient charge carrier transfer. Moreover, the optimized CMC-7.5 photoelectrode has a superior integral area and exhibited excellent stability over 100 cycles. Finally, the study outlines the construction of several advanced materials with multi-interface heterojunctions involving cation-exchanged LDH derivatives with high photogenerated charge carrier separation efficiency and minimal interfacial migration resistance to serve as stability benchmarks for practical applications.

Mxene quantum dots decorated reduced graphene oxide networks as multifunctional electrocatalyst for advanced lithium–sulfur batteries

Lithium sulfur (Li-S) battery has shown great potential as an attractive rechargeable energy storage devices, but the shuttle behavior and slow conversion kinetics of the intermediate lithium polysulfides (LiPSs) are the main obstacles to the practical application of Li-S battery. Herein, a simple and scalable spray drying strategy was used to construct conductive polar Ti3C2 MXene quantum dots (QDs)-decorated reduced graphene oxide (rGO) microsphere (rGO@Ti3C2 QDs) as efficient electrocatalyst and absorbent for Li-S battery. Firstly, the DFT results show that Ti3C2 QDs can effectively adsorb and catalyze LiPSs conversion. This ability can be attributed to the Ti3C2 QDs can provide a large number of LiPSs catalytic active sites. In addition, the rGO provides physical LiPSs constraint and a flexible substrate to prevent QDs from aggregating. Moreover, both parts are conductive, effectively improving the electron/charge transfer. Therefore, this unique structure and composition show high LiPSs adsorption and catalysis, while allowing rapid Li+/electron transfer. As a result, the S/rGO@Ti3C2 QDs electrode provides high initial capacity (1185 mAh/g at 0.2C), good rate capability (758 mAh/g at 3C), and excellent long-term cyclability (500 cycles at 1C with low attenuation of 0.07% per cycle), as well as an excellent electrochemical performance even at high sulfur loading. Meanwhile, the Li-S pouch cell based on S/rGO@Ti3C2 QDs also achieved a high initial energy density of 230.9 Wh kg−1. This work may provide a promising strategy to obtain better electrochemical performance by introducing quantum dots into Li-S cathodes.

Cooperative Cu with defective MXene for enhanced nitrate electroreduction to ammonia

AbstractThe electroreduction of nitrate (NO3RR) to ammonia (NH3) provides a promising solution to enable environmental remediation caused by ‐containing waste and also allows for energy‐saving NH3 generation. Adsorption of *NO2 intermediate may be strengthened to decrease byproducts (e.g., ) and favor the eight‐electron NO3RR into NH3. In this work, copper‐incorporated O‐vacancy containing Ti3C2 MXene (Cu@Ti3C2Ov) is reported, which cooperatively inhibits production and facilitates hydrogenation, leading to approximately 100% Faradaic efficiencies of NH3 and high yield rates at various potentials. Density functional theory calculations show that and the *NO2 intermediates have a significant interaction with the Cu@Ti3C2Ov catalyst. Moreover, the formation of has a high energy barrier, which explains the appealing catalytic performance of the Cu@Ti3C2Ov toward NO3RR with suppressed and elevated NH3 selectivity. This work would motivate the prudent design of new catalysts for high‐performance NO3RR to NH3 by elucidating the significance of stabilizing the *NO2 intermediate.

Regulating nitrogen/sulfur terminals on 3D porous Ti3C2 MXene with enhanced reaction kinetics toward high-performance alkali metal ion storage

In this paper, we have developed a simple and efficient sulfur-amine chemistry strategy to prepare a three-dimensional (3D) porous Ti3C2Tx composite with large amounts of N and S terminal groups. The well-designed 3D macroporous architecture presents enlarged interlayer spacing, large specific surface area, and unique porous structure, which successfully solves the re-stacking issue of MXene during storage and electrode fabrication. It is the amount of concentrated hydrochloric acid added to the S-EDA (ethylenediamine)/MXene colloidal suspension that is critical to the formation of 3D morphology. In addition, N and S terminals on MXene could improve the adsorption ability of K+. Owing to the synergistic effect of the structure design and terminal modification, the N, S codoped three-dimensional porous Ti3C2Tx (3D-NSPM) material shows a high surface capacitive contribution and rapid diffusion kinetics for K+ and Na+. As a result, the as-prepared 3D-NSPM delivers high reversible capacity (237 and 273 mAh g−1 at 0.1 A g−1 for PIBs and SIBs, respectively), superb cycling stability (84.9% capacity retention after 10,000 cycles at 1 A g−1 in PIBs and 74.0% capacity retention after 2200 cycles at 1 A g−1 in SIBs), and excellent rate capability (111 and 196 mAh g−1 at 5 A g−1 for PIBs and SIBs, respectively), which are superior to other MXene-based anodes for PIBs and SIBs. Moreover, the described strategy provides a new insight for constructing the 3D porous structure from 2D building blocks beyond MXene.

Self-validating photothermal and electrochemical dual-mode sensing based on Hg2+ etching Ti3C2 MXene

Mercury ions can cause serious damage to the ecological environment, and it is necessary to develop reliable and elegant mercury ion sensors. In this protocol, a label-free photothermal/electrochemical dual-mode strategy for Hg2+ is proposed based on delaminated Ti3C2 MXene nanosheets (DL-Ti3C2 MXene). Hg2+ exists in water in the form of HgCl2, Hg(OH)2, and HgClOH, and the electron-rich elements O and Cl can specifically bind to the positively charged DL-Ti3C2 MXene at the edge, and further oxidation-reduction reaction occurs to obtain TiO2/C and Hg2Cl2. In view of the reduction activity and the performance of photothermal conversion of DL-Ti3C2 MXene itself, the electrochemical and photothermal responses decrease with the increase of the logarithm of Hg2+ concentration. The corresponding linear ranges are 50 pmol L−1-500 nmol L−1 and 1 nmol L−1-50 μmol L−1, and their detection limits calculated at 3 S/N are 17.2 pmol L−1 and 0.43 nmol L−1, respectively. DL-Ti3C2 MXene has the characteristics of a wide range of raw materials, low cost, and easy preparation. In addition, the design takes full advantage of the properties of the material itself, avoids the complex assembly and detection process of conventional sensors, and enables high selectivity and sensitivity for mercury detection. In particular, the dual-mode sensing endows self-confirmation of mercury ion detection results, thereby improving the reliability of the sensor.

Electro‐Conductive Ti3C2 MXene Multilayered Membranes: Dye Removal and Antifouling Performance

AbstractThis work describes the fabrication of a novel electroconductive membrane made of Ti3C2Tx (MXene) nanosheet coating through a one‐step pressure‐assisted technique. Ti3C2‐MXene is firmly attached over a polyamide–imide (PAI) microfilter by employing a binder composed of carboxymethyl cellulose (CMC)/glutaraldehyde (GA). Through coating a proper amount of multilayer Ti3C2‐MXene, the electrical conductivity of 174 ± 0.16 S m−1 is achieved. The rejection rates of reactive red 120 (RR120), reactive black (RB), and methyl orange (MO) by the pristine PAI membrane are 45.2%, 40.81%, and 33.65%, respectively. However, rejection rates significantly improve with the Ti3C2 MXene coating to over 99.71%, 97.95%, and 68.91% for RR120, RB, and MO. Applying a 4 V cathodic potential resulted in a flux recovery ratio (FRR) of 99.83% and a flux decline rate (FDR) of less than 1% during humic acid (HA) filtration. Without applying voltage, the MXene‐coated membrane shows an FRR and FDR of 92.51% and 45.56%, respectively. Surface energy analysis reveals strong repulsive interactions between foulants and the membrane surface. Moreover, the surface free energy indicates that foulants such as sodium alginate (SA) and bovine serum albumin (BSA) exhibit stronger adhesion to the membrane than HA, consistent with the fouling experiment results.