Multilayer Ti3C2 Research Articles

Nanofluidic sensing inspired by the anomalous water dynamics in electrical angstrom-scale channels

Manipulation of confined water dynamics by voltage keeps great importance for diverse applications. However, limitations on the membrane functions, voltage-control range, and unclear dynamics need to be addressed. Herein, we report an anomalous electrically controlled gating phenomenon on cation-intercalated multi-layer Ti3C2 membranes and reveal the confined water dynamics. The water permeation rate was improved rapidly following the application and rise of voltage and finally reached a maximum rate at 0.9 V. The permeation rate starts to decrease from 0.9 V. Below 0.9 V, the electric field affects the charge and polarity of water molecules and then leads to ordered and denser rearrangement in the two-dimensional (2D) channel to accelerate the permeation rate. Above 0.9 V, with the assistance of metal cations, the surge in current induced aggregation of water molecules into clusters, thereby limiting the water mobility. Based on these findings, a high-performance humidity sensor was developed by simultaneously optimizing the response and recovery speeds through electric manipulation. This work provides flexible strategies in intelligent membrane design and nanofluidic sensing.

Multilayer Ti3C2-CNTs-Au Loaded with Cyclodextrin-MOF for Enhanced Selective Detection of Rutin.

In this work, multi-layer Ti3C2 - carbon nanotubes - gold nanoparticles (Ti3C2-CNTs-Au) and cyclodextrin metal-organic framework - carbon nanotubes (CD-MOF-CNTs) have been prepared by in situ growth method and used to construct the ultra-sensitive rutin electrochemical sensor for the first time. Among them, the large number of metal active sites of Ti3C2, the high electron transfer efficiency of CNTS, and the good catalytic properties of AuNPs significantly enhance the electrochemical properties of the composite carbon nanomaterials. Interestingly, CD-MOF has a unique host-guest recognition and a large number of cavities, molecular gaps, and surface reactive groups, which gives the composite outstanding accumulation properties and selectivity for rutin. Under the optimized conditions, the constructed novel sensor has satisfactory detection performance for rutin in the range of 2 × 10-9 to 8 × 10-7M with a limit of detection of 6.5 × 10-10M. In addition, the sensor exhibits amazing anti-interference performance against rutin in some flavonoid compounds and can be used to test natural plant samples (buckwheat, Cymbopogon distans, and flos sophorae immaturus). This work has promising applications in the field of environmental and food analysis, and exploring new directions for the application of Mxene-based composites.

2D TiO2/Ti3C2 conductive substrate enhanced the photoelectrochemical performance of hematite for water splitting

Since the photoelectrochemical properties of hematite are affected by its bulk and surface charge recombination, the introduction of a conductive substrate is a feasible way to improve its properties. In this paper, the Ti3C2 and TiO2/Ti3C2 conductive substrates were prepared by electrophoretic depositing multilayered Ti3C2 and TiO2/Ti3C2 nanosheet powders onto F-doped SnO2 glass (FTO), respectively. Then, the TiO2/Ti3C2-hematite and Ti3C2-hematite photoanodes were obtained by in-situ growth of hematite on Ti3C2 and TiO2/Ti3C2 conductive substrates by hydrothermal method. The photoanodes were characterized by scanning electron microscopy (SEM), UV–vis spectroscopy, X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS) and photoelectrical measurements. The photocurrent density of TiO2/Ti3C2-hematite reaches 1.29 mA cm−2 at 1.23 V (vs. RHE), which is 3.7 times than that of the FTO-hematite as 0.35 mA cm−2. The enhancement of the photocurrent response of TiO2/Ti3C2-hematite is mainly due to the great improvement of the bulk charge separation efficiency and the surface charge injection efficiency. This is attributed to the fact that the layered TiO2/Ti3C2 conductive substrate can improve the interface property of FTO/hematite, provide Ti source and a larger specific surface area for the growth of hematite.

Step-by-Step Guide for Synthesis and Delamination of Ti3 C2 Tx MXene.

To advance the MXene field, it is crucial to optimize each step of the synthesis process and create a detailed, systematic guide for synthesizing high-quality MXene that can be consistently reproduced. In this study, a detailed guide is provided for an optimized synthesis of titanium carbide (Ti3 C2 Tx ) MXene using a mixture of hydrofluoric and hydrochloric acids for the selective etching of the stoichimetric-Ti3 AlC2 MAX phase and delamination of the etched multilayered Ti3 C2 Tx MXene using lithium chloride at 65 °C for 1 h with argon bubbling. The effect of different synthesis variables is investigated, including the stoichiometry of the mixed powders to synthesize Ti3 AlC2 , pre-etch impurity removal conditions, selective etching, storage, and drying of MXene multilayer powder, and the subsequent delamination conditions. The synthesis yield and the MXene film electrical conductivity are used as the two parameters to evaluate the MXene quality. Also the MXenes are characterized with scanning electron microscopy, x-ray diffraction, atomic force microscopy, and ellipsometry. The Ti3 C2 Tx film made via the optimized method shows electrical conductivity as high as ≈21,000 S/cm with a synthesis yield of up to 38 %. A detailed protocol is also provided for the Ti3 C2 Tx MXene synthesis as the supporting information for this study.

Pt nanoparticles anchored on Ti3C2 MXene‐derived TiO2 nanosheets for enhanced hydrogen evolution reaction

AbstractPlatinum (Pt)‐based electrocatalysts are the most excellent catalysts for hydrogen evolution reaction (HER). But Pt is limited and expensive on earth, adding the proper matrix to disperse and anchor Pt is a viable way to reduce Pt consumption. Based on the excellent structure and electrochemical properties of two‐dimensional (2D) MXene, the Ti3C2 MXene‐derived TiO2 supported Pt nanoparticles (NPs) catalysts should have good catalytic performance in theoretically, but it has not been studied in experimentally. In this study, Pt NPs were anchored on the multilayer Ti3C2 MXene‐derived TiO2 nanosheets (NSs) to obtain super catalyst. The as‐prepared Pt/TiO2/Ti3C2 catalyst exhibited excellent HER performance under acidic conditions, with an overpotential of 147 mV and a small Tafel slope (54 mv dec−1) at 10 mA cm−2. Meanwhile, it has good stability under acidic conditions, and the activity has no obvious attenuation after 1000 CV cycles. In addition, the results show that anchoring Pt NPs on Ti3C2 MXene‐derived TiO2 NSs can help to reduce the binding energy and hybridization strength between H atoms and the support, thereby promoting the fast hydrogen adsorption‐desorption kinetics and enhancing the activity of HER. This work provides a new avenue for rational construction of high‐performance Ti3C2‐based catalysts.

3D printing aqueous Ti3C2Tx inks for MXene-based energy devices

The in situ HF acid etching of Ti3AlC2 yielded multilayered Ti3C2. Sonication delaminated nanosheets, suspended in DI water, post rheological optimization 3D printed using DIW platform to produce conductive patterns of MXene.

Efficient Interfacial Charge Transfer Based on 2D/2D Heterojunctions of Fe-C3N4/Ti3C2 for Improving the Photocatalytic Degradation of Antibiotics.

Graphitic carbon nitride (g-C3N4) has shown to be a promising photocatalyst that, however, suffers from strong charge recombination and poor conductivity, while MXenes have shown to be perfect cocatalysts for the photocatalytic process but show poor stability. In this study, we successfully constructed 2D/2D heterojunctions of Fe-C3N4/Ti3C2 for the photocatalytic degradation of antibiotics. In this study, multilayer Ti3C2 was obtained by etching Ti3AlC2, and then Fe-C3N4/Ti3C2 photocatalyst was prepared by the one-pot microwave method and high-temperature calcination method. The synthesized samples were characterized by XRD, SEM, TEM, XPS, TGA, BET, DRS, PL, and other means. The photocatalytic degradation of tetracycline hydrochloride by Fe-C3N4/Ti3C2 was in accordance with the first-order reaction kinetics model, and the apparent rate constant k was 2.83, 2.06, and 1.77 times that of g-C3N4, Fe-C3N4, and g-C3N4/Ti3C2, respectively. Through the mechanism study, it was shown that the most active species in the reaction system was • O2 −, while h+ and •OH had a relatively lower effect on the degradation system.

A high-sensitive dopamine electrochemical sensor based on multilayer Ti3C2 MXene, graphitized multi-walled carbon nanotubes and ZnO nanospheres

Dopamine is one of the most important neurotransmitters in the human body, and its sensitive detection and quantification are important for the diagnosis, prevention, and treatment of related neurological diseases. Herein, a highly-sensitive dopamine electrochemical sensor has been constructed based on the two-dimensional transition metal carbide Ti3C2 MXene, graphitized multi-walled carbon nanotubes and ZnO nanospheres. Dopamine presents a standard reversible redox reaction on the sensor, and density flooding theory has been successfully applied to reveal the redox process of dopamine. Under optimal experimental conditions, the sensor exhibits a wide linear range (0.01–30 μM), low limit of detection (3.2 nM) and high sensitivity (16 A/M). Furthermore, the sensor has excellent stability and anti-interference ability, satisfactory accuracy in human serum samples, which can be used for the detection of actual samples. This work has provided a novel method for detecting dopamine and a new idea for the application of MXene and metal oxide semiconductor in electrochemical sensors.

Synthesis of Ti3C2 MXene@PANI composites for excellent anticorrosion performance of waterborne epoxy coating

Ti3C2 MXene nanosheets have become a research hotspot in the anticorrosion field owing to their excellent barrier performance and mechanical properties. However, the utilization of different etching agents for the preparation of Ti3C2 MXene nanosheets has positive or negative influence on corrosion protection of waterborne epoxy coating (WEP) for metal owing to their quiet distinct electrical conductivity. In this study, we successfully synthesized multilayer Ti3C2 MXene nanosheets, and Ti3C2 MXene@PANI composites, such that PANI with high doping levels were uniformly anchored on the Ti3C2 MXene nanosheets' surface via in situ intercalation polymerization. Moreover, we verified the LiF and HCl treatment of Ti3C2 MXene accelerated the failure of WEP coating, which can be attributed to its higher electrical conductivity caused by the intercalation of Li+ than that of HF treatment. Ti3C2 MXene@PANI composites significantly improved the corrosion resistance of the WEP coating, thus greatly resolving the accelerating corrosion issue of Ti3C2 MXene. 0.3 wt% or more Ti3C2 MXene@PANI-1.0/WEP coatings' corrosion current density, impedance modulus, and charge transfer resistance increased by 1–2 orders of magnitude than that of pure WEP and Ti3C2 MXene/WEP in 3.5 wt% NaCl after 10 days of immersion. These results demonstrated that the synergistic effect of Ti3C2 MXene nanosheets' barrier effect and PANI's passivation effect enable Ti3C2 MXene@PANI composites with lower electrical conductivity to achieve long-term and efficient corrosion protection in WEP coating for Q235 steel.

Promoted charge separation on 3D interconnected Ti3C2/MoS2/CdS composite for enhanced photocatalytic H2 production

The construction of heterojunction has been regarded as an effective way to promote photocatalytic H2 evolution activity, in which an intimately interfacial contact between the materials forming heterojunction is a positive effect on enhancing activity. Herein, a ternary 3D interconnected nanocomposite Ti3C2/MoS2/CdS was synthesized by a hydrothermal method. MoS2 nanosheet with a vertically aligned structure grew on the surface of multi-layered Ti3C2 to form 3D Ti3C2/MoS2 with tightly interfacial contact, which works as a cocatalyst for enhancing photocatalytic H2 evolution. CdS as a photocatalyst covered the surface of Ti3C2/MoS2 to absorb light energy. Benefitting to the synergistic effect between Ti3C2 and MoS2, the Ti3C2/MoS2 further accelerates electron transfer and inhibits the recombination of carriers. The H2 evolution rate of Ti3C2/MoS2/CdS reaches 15.2 mmol h−1 g−1 and the apparent quantum yield is 42.1% at λ = 420 nm. The result provides a useful insight for developing cocatalysts with new nanostructures via controlled interfacial engineering.

2D/2D nanohybrid of Ti3C2 MXene/WO3 photocatalytic membranes for efficient water purification

Photocatalytic membrane is attracting a great deal of current attention for water decontamination by taking the full advantage of photocatalysis and membrane separation. Herein, the well-defined WO3 nanoplates are homogeneously dispersed onto the surface of multilayer Ti3C2 MXene to create a novel 2D/2D nanohybrid with various Ti3C2 contents (3–7 wt%) through a facile and cost-effective approach, and then photocatalytic membrane system is developed by anchoring these heterostructured-photocatalysts on polyvinylidene fluoride (PVDF) membrane by means of vacuum filtration. Ti3C2/WO3/PVDF photocatalytic membranes exhibit enhanced RhB degradation and cyclability, alongside with refreshing behavior under visible-light illumination. We demonstrate that the excellent electrical conductivity of Ti3C2, the formation of built-in electric field and the large interface contact area between Ti3C2 and WO3 synergetically promote the spatial charge separation and increase the surface reactive sites, which is responsible for boosting the photoreactivity and photostability. Besides, a significant high flux recovery of ∼ 94% is obtained by 5 wt% Ti3C2/WO3/PVDF membrane under visible light irradiation. This study opens possibilities to construct multi-functional and robust MXenes-based photocatalytic membrane for long-term water purification.

Non-toxic 2D Ti[formula omitted]C[formula omitted] MXene surface-modified with Al, Ga, In alkoxides by chemical reactions with metal trialkyls

Understanding the surface chemistry and reactivity of 2D MXenes is of fundamental importance in developing more advanced functional materials. In this work, we describe multilayered Ti3C2 MXene-based materials such as Ti3C2/Al3＋, Ti3C2/In3+ and Ti3C2/Ga3+, obtained by modifying the MXene surface with aluminum-, indium- and gallium alkoxides. In the synthesis of these materials, organometallic compounds of group 13 metals (Et3Al, Me3In, and Et3Ga) were chosen as precursors for the alkoxides to modify the surface. To attach organometallic compounds to the MXene surface, their high reactivity towards the terminal OH, = O and F groups present on the MXene surface was used. In the next step, exposure of the surface-attached aluminum-, indium and gallium alkyls to air allowed their transformation into metal alkoxides due to the high reactivity of the metal-carbon bonds to oxygen and water. In our method of MXene modification, the alkoxide precursors can be extended to other organometallic compounds, such as groups 1, 2 and 12 alkyls. Microbiological studies of the developed 2D Ti3C2/Al3＋, Ti3C2/In3+ and Ti3C2/Ga3+ alkoxides showed no acute ecotoxicity to the tested microorganisms. The obtained materials did not influence bioluminescent/biosensor-type microorganisms nor reduce the viability of other types of microorganisms, such as Staphylococcus aureus, Escherichia coli or Candida albicans. The obtained results clearly indicate that the surface modification of 2D Ti3C2 MXene with group 13 metal compounds is highly prospective toward the development of various types of materials that do not show any adverse effects to living organisms.

Investigation on Tribological and Thermo-Mechanical Properties of Ti3C2 Nanosheets/Epoxy Nanocomposites.

In this study, two-dimensional Ti3C2 nanosheets were employed to improve the tribological and thermo-mechanical properties of epoxy resin. The Ti3C2 nanosheets were prepared by ultrasound-assisted delamination of multilayered Ti3C2 microparticles, and the Ti3C2 nanosheets/epoxy (Ti3C2/epoxy) nanocomposites were fabricated through physical blending and curing reaction. Scanning electron microscopy results showed that the Ti3C2 nanosheets were dispersed uniformly in the epoxy matrix. Tribological test results showed that the wear rate of Ti3C2/epoxy nanocomposites was only 6.61 × 10–14 m3/(N m) at a 1% mass fraction, which was reduced by 72.1% compared to that of neat epoxy. The morphologies of worn surfaces revealed that the wear form of Ti3C2/epoxy nanocomposites transformed gradually from fatigue wear to adhesive wear with the increase of mass fraction of Ti3C2 nanosheets. Moreover, the results of thermo-mechanical properties indicated that incorporation of Ti3C2 nanosheets effectively improved the storage modulus and glass-transition temperature (Tg) of epoxy resin. This work provides guidance for improving the tribological and thermo-mechanical properties of epoxy resin.

Ten Years of Progress in the Synthesis and Development of MXenes (Adv. Mater. 39/2021)

MXenes In article number 2103393, Michael Naguib, Michel W. Barsoum, and Yury Gogotsi present a brief historical overview of the first 10 years of MXene research and a perspective on their synthesis and future development. The cover shows a colored SEM image of a multilayer Ti3C2 MXene particle with an accordion-like morphology, which is produced by individual MXene layers stacked together. The variety of colors represents the diversity of MXene structures and compositions. Image Credit: The SEM image was taken by Dr. Tyler Mathis and colored by Dr. Armin VahidMohammadi.

The Improvement in Hydrogen Storage Performance of MgH2 Enabled by Multilayer Ti3C2.

MgH2 has become a hot spot in the research of hydrogen storage materials, due to its high theoretical hydrogen storage capacity. However, the poor kinetics and thermodynamic properties of hydrogen absorption and desorption seriously hinder the development of this material. Ti-based materials can lead to good effects in terms of reducing the temperature of MgH2 in hydrogen absorption and desorption. MXene is a novel two-dimensional transition metal carbide or carbonitride similar in structure to graphene. Ti3C2 is one of the earliest and most widely used MXenes. Single-layer Ti3C2 can only exist in solution; in comparison, multilayer Ti3C2 (ML-Ti3C2) also exists as a solid powder. Thus, ML-Ti3C2 can be easily composited with MgH2. The MgH2+ML-Ti3C2 composite hydrogen storage system was successfully synthesized by ball milling. The experimental results show that the initial desorption temperature of MgH2-6 wt.% ML-Ti3C2 is reduced to 142 °C with a capacity of 6.56 wt.%. The Ea of hydrogen desorption in the MgH2-6 wt.% ML-Ti3C2 hydrogen storage system is approximately 99 kJ/mol, which is 35.3% lower than that of pristine MgH2. The enhancement of kinetics in hydrogen absorption and desorption by ML-Ti3C2 can be attributed to two synergistic effects: one is that Ti facilitates the easier dissociation or recombination of hydrogen molecules, while the other is that electron transfer generated by multivalent Ti promotes the easier conversion of hydrogen. These findings help to guide the hydrogen storage properties of metal hydrides doped with MXene.

Ultrasensitive dual-quenching electrochemiluminescence immunosensor for prostate specific antigen detection based on graphitic carbon nitride quantum dots as an emitter.

Early monitoring of prostate-specific antigen (PSA) is crucial in diagnosis and proactive treatment of prostate disease. Herein, a dual-quenching ternary ECL immunosensor was designed for PSA detection based on graphitic carbon nitride quantum dots (g-CNQDs, as an emitter), potassium persulfate (K2S2O8, as a coreactant), and silver nanoparticles doped multilayer Ti3C2 MXene hybrids (Ag@TCM, as a coreaction accelerator). First, Ag@TCM was immobilized on the surface of a glassy carbon electrode, then g-CNQDs was further adsorbed on Ag@TCM to acquire a higher initial ECL signal at a potential window from - 1.3 to 0.0V (vs. Ag/AgCl). Ag@TCM not only acted as the coreaction accelerator, but also as a matrix to load enormous g-CNQDs and prostate-specific capture antibody via Ag-N bond. Meanwhile, prostate-specific detection antibody was marked by gold nanoparticles modified manganese dioxide as a dual-quenching probe (Ab2- Au@MnO2). When Ab2-Au@MnO2 was introduced into the ternary ECL system via sandwiched immuno-reaction, the high-sensitive detection of PSA was achieved by the dual-quenching effect, caused by the resonant energy transfer from g-CNQDs (energy donor) to Au@MnO2 (energy acceptor). As a result, this ECL immunosensor showed a good dynamic concentration range from 10fg·mL-1 to 100ng·mL-1 with a detection limit of 6.9fg·mL-1 for PSA detection. The dual-quenching ECL strategy presented high stability and good specificity to open up a new pathway for ultrasensitive immunoassay.

Electrochemical Performance and Charge Storage Mechanism of Few-Layer MXene Titanium Carbide for Supercapacitors

MXene Titanium Carbide has attracted extensive attention in the application fields of energy storage devices such as supercapacitors. However, most scholars study multi-layer MXene Ti3C2 and its composite. In particular, the effect of few-layer Ti3C2 on electrochemical performance and the charge storage mechanism in the process of energy storage still need to be further explored. To improve the specific capacitance, a microwave assisted hydrothermal technique was used to prepare few-layer Ti3C2. The microstructure of few-layer Ti3C2 was further analyzed by SEM and TEM. The dense Ti3AlC2 (0002) planes were bent and van der Waals bonds between the layers broken. The layers became more distorted under the joint action of etching agent and microwave hydrothermal solution, finally fractured and dissociated, forming few-layer Ti3C2. The mass specific capacitance of few-layer Ti3C2 is 418.07 F g−1, which is 102.63% higher than that of multi-layer Ti3C2. Through the kinetic analysis of the electrochemical energy storage processes, it was found that the charge storage of the few-layer Ti3C2 is mainly from the contribution of the surface capacitance. This provides a new direction for the simple and efficient synthesis of high specific mass capacitance MXene Ti3C2 as electrode material for supercapacitors.

High-energy ball milling assisted one-step preparation of g-C3N4/TiO2@Ti3C2 composites for effective visible light degradation of pollutants

Degradation and mineralization of pollutants has attracted great interest because of its ability to resolve some global environmental water-related issue. In this study, we synthesized ternary Z-type photocatalytic materials g-C3N4/TiO2@Ti3C2 with multilayer Ti3C2 as the carrier, loaded with g-C3N4 and in situ oxidized TiO2 by one-step calcination assisted by high-energy ball milling using g-C3N4 precursors (CAM) and MXene as raw materials. The influence of Ti3C2 addition and calcination temperature on the degradation efficiency of the composites were explored. Also, phase composition, microscopic morphology and optical properties of the g-C3N4/TiO2@Ti3C2 ternary composites were characterized. When Ti3C2 was added at 60 mg, the calcination temperature was 580 °C, composites showed eximious catalytic activity with Methyl Orange (MO) degradation rate, which is 3.62 times that of g-C3N4 and 6.60 times as that of Ti3C2. The improvement in photocatalytic performance is formed due to Z-type heterojunctions in the composites, and the close connect among the multilayer Ti3C2, perforated g-C3N4 flake with huge specific surface area and oxidation-generated TiO2 promotes the separation of photocatalytic carriers and the catalytic reaction. In addition, Ti3C2 acts as a transport medium for the Z-type heterojunction structure, further promoting phototransfer of electrons. This project shows that the g-C3N4/TiO2@Ti3C2 composites have prominent development prospects and provide an important reference for the design of ternary heterojunction materials.

Preparation of Ti3 C2 Tx MXene based solid-phase microextraction coating for sensitive determination of polychlorinated biphenyls in environmental water samples.

In this study, a new Ti3 C2 Tx -coated fiber was synthesized and utilized as coatings for solid-phase microextraction of seven polychlorinated biphenyls. The as-produced multilayered Ti3 C2 Tx MXene was characterized by X-ray diffractometer, thermos-gravimetric analysis, scanning electron microscopy, and energy dispersive spectroscopy. It is noteworthy that the Ti3 C2 Tx showed some attractive features including unique 2D layered structures, large surface area, good hydrophilicity, and rich active recognition sites, endowing it has a high affinity towards the target polychlorinated biphenyls. Subsequently, the affecting parameters on the extraction efficiency of polychlorinated biphenyls were optimized. Under the optimal conditions, a novel method for the analysis of polychlorinated biphenyls in water samples was proposed. The Ti3 C2 Tx -coated fiber-based solid-phase microextraction method showed good linearity (r2 >0.9928), high enrichment factors (268-442), low limits of detection (0.06-0.15ng/L), and satisfactory repeatability (RSDs<7.5%) for the polychlorinated biphenyls. The excellent method recoveries were in the range of 90.0-98.4, 92.0-98.2, and 92.0-98.0% for river water, lake water, and tap water samples, respectively. These results suggested that the proposed Ti3 C2 Tx -coated fiber-based method represents a promising alternative for the analysis of polychlorinated biphenyls.

Enhanced NO2 gas-sensing performance of 2D Ti3C2/TiO2 nanocomposites by in-situ formation of Schottky barrier

Two-dimensional (2D) Ti3C2 MXene, derived from the Ti3AlC2 MAX phase, is a potential candidate for gas sensing materials due to its high conductivity, but it has a shortcoming of weak sensitivity towards gases. Here, we firstly synthesized Ti3C2/TiO2 nanocomposites by in-situ growth of TiO2 on the surface of multilayer Ti3C2 MXene via a hydrothermal oxidation process, and investigated the gas-sensing performances (involving response, operation temperature and selectivity) of Ti3C2/TiO2 composites by combining experiments and first-principles calculations. The experimental results show that the hydrothermal oxidation temperature plays a key role in the morphology evolution and gas-sensing performance of Ti3C2/TiO2 composites. Compared to the pristine Ti3C2, the Ti3C2/TiO2 composites display outstanding response to NO2 gas due to the formation of a Schottky barrier at the Ti3C2/TiO2 interface, as a result of that the excellent response of ~ 1.13 to 5 ppm NO2 is achieved at room temperature. In particular, the optimal Ti3C2/TiO2 composite presents higher response value (86 times) and faster response and recovery time (2 and 3.8 times) to 100 ppm NO2 than pristine Ti3C2 at optimum temperatures, and shows good selectivity and linear response to NO2 gas. This work provides a simple process to in-situ form the Schottky barrier for improving the gas-sensing performance of pristine MXene in practical applications.