Layered Ti3C2 Research Articles

Novel sensitive electrochemical detection of paracetamol using magnetite/MXene electrode by differential pulse voltammetry

In this research work, a novel electrochemical sensor-based Fe3O4/Ti3C2 MXene @ glassy carbon electrode (GCE) for the detection of paracetamol was prepared by simple ultrasonic method by combining Ti3C2 MXene and Fe3O4 nanoparticles. The Fe3O4/Ti3C2 MXene nanomaterial was characterized by the means of different techniques: X-ray diffraction (XRD), transmission and scanning electron microscopy (TEM), nitrogen adsorption/desorption isotherms, as well as Fourier transform infrared spectroscopy (FTIR). The characterization results revealed the homogenous distribution of the prepared cubic Fe3O4 NPs within the prepared two-dimensional layered Ti3C2 MXene. The Fe3O4/Ti3C2 MXene @ GCE was used for the sensitive determination of the well-known analgesic drug paracetamol by differential pulse voltammetry (DPV). The prepared Fe3O4/Ti3C2 MXene @ GCE was characterized electrochemically, and the results showed that Fe3O4/Ti3C2 MXene @ GCE is a potential working electrode for the sensitive detection of paracetamol with very low detection limit (0.63 nM), within a linear dynamic range of 0.0–110.0 µM, high reproducibility and repeatability; with a very low relative standard deviation (SD%) for 7 days measurement (3.07–3.42 %), accuracy with a SD% of 0.89, high precision of 99.48 % in distilled water and 98.51 % in sea water. The proposed electroanalytical method was applied for the detection and quantification of paracetamol in real water samples, as well as different analgesic medical formulations, and the results showed outstanding accuracy and precision indicating the suitability of the Fe3O4/Ti3C2 MXene @ GCE electrode for the sensitive, accurate determination of paracetamol in diferrent matrices.

Magnetite/MXene (Fe3O4/Ti3C2) Nanocomposite as a Novel Adsorbent for Environmental Remediation of Malachite Green Dye.

In this work, a novel adsorbent called magnetite/MXene (Fe3O4/Ti3C2) nanocomposite was prepared, characterized, and applied for the removal of organic dye, malachite green dye (MG), from both real water and model solutions. Numerous techniques were used to characterize the prepared Fe3O4/Ti3C2 nanocomposite: XRD, SEM, TEM, FTIR, and surface area analysis. The outcomes showed that the Al layer had been selectively etched, that the MAX phase (Ti3AlC2) had been transformed into layered Ti3C2 MXene, that the cubic Fe3O4 phase had been prepared, and that the prepared Fe3O4 NPs had been evenly distributed on the MXene surface. Also, SEM pictures showed the successful etching of the MAX phase and the formation of the ultrathin multi-layered MXene, which the Fe3O4 NPs covered upon forming the Fe3O4/Ti3C2 nanocomposite at the surface and inside the ultrathin multi-layered MXene. The effect of different operational parameters affecting the removal process was explored and optimized. The MG dye was removed mostly within 60 min, with a 4.68 mg/g removal capacity using 5 mg of the Fe3O4/Ti3C2 nanocomposite. The removal was examined from both kinetic and thermodynamic perspectives, and the findings demonstrated the spontaneity of the removal process as well as the applicability of fractal-like pseudo-first-order and fractal-like pseudo-second-order kinetics when compared to other kinetics models. The Fe3O4/Ti3C2 nanocomposite was used to remove MG dye from real spiked environmental water samples, and the results revealed the successful remediation of the real samples from the organic dye by the Fe3O4/Ti3C2 nanocomposite. Accordingly, Fe3O4/Ti3C2 nanocomposite could be considered a potential adsorbent for the environmental remediation of polluted water.

Ti3C2@UiO−TCPP Schottky junction photoelectrochemical sensor for detecting alkaline phosphatase through the steric hindrance effect of phosphopeptide

Alkaline phosphatase (ALP) is a major biomarker for clinical diagnosis, but detection methods of ALP are limited in sensitivity and selectivity. In this paper, a novel method for ALP determination is proposed. A photoelectrochemical (PEC) sensor was prepared by growing UiO−tetratopic tetrakis (4-carbox-yphenyl) porphyrin (TCPP) in situ between layered Ti3C2 through a one-pot hydrothermal method. The obtained Schottky heterojunction photoelectric material Ti3C2@UiO−TCPP not only has a large light absorption range but also greatly improves the efficiency of photogenerated electron hole separation and thereby enhances sensitivity for PEC detection. The phosphate group on the phosphorylated polypeptide was utilized to form a Zr–O–P bond with the zirconium ion on UiO-66, and then photocurrent decreases due to the steric hindrance effect of phosphorylated polypeptides, that is, the hindrance of electron transfer between the photoelectric material and a solution. The specific interaction between ALP and phosphorylated polypeptides shears the bond between phosphate and zirconium ion on UiO-66 in the peptides then weakens the hindrance effect and increases the photocurrent, thus realizing ALP detection. The linear range of ALP is 0.03–10,000 U·L−1, and the detection limit is 0.012 U·L−1. The method is highly sensitive and selective, and has been applied in detection of ALP in serum samples.

Synergetic effect of Ti3C2-X (X = Fe, Co, Ni) on enhanced hydrogen storage performance of MgH2-TiCrV composite

MgH2 has been attracted extensive attention because of its superior hydrogen storage performance and good reversibility. Further improvement of its kinetics and thermodynamic performances is needed to achieve widespread application. This article investigated the hydrogen storage properties of the thermodynamic optimized Mg-TiCrV hydrogen storage composite modified by layered Ti3C2 materials containing different 3d transition metal particles (Fe, Co, Ni). Mg-TiCrV/Ti3C2-X (X = Fe, Co, Ni) composites can absorb more than 5.30 wt% hydrogen within 1 min at 453 K under 3 MPa hydrogen pressure, and desorb more than 5.25 wt% hydrogen within 60 min at 543 K to 0.1 MPa. In particular, Mg-TiCrV/Ti3C2-Ni composite exhibited the best hydrogen storage properties, which can desorb 4.98 wt% hydrogen within 60 min at 523 K to 0.1 MPa hydrogen pressure and absorb 5.80 wt% hydrogen within 1 min at 453 K under 3 MPa hydrogen pressure. Structural analysis shows that the synergistic effect of layered material Ti3C2 and Ni particles promote the hydrogen release and uptake process.

MXene-derived composite catalyst with micro-holes by a solvothermal method with tiny amount of solvent for high-efficiency catalytic hydrogen production

A strategy is reported here to introduce micro-holes in the two-dimensional layered Ti3C2 by the tiny-solve-thermal method. TiO2 grows situ either in holes and between or on layers of Ti3C2 using this method meanwhile. The special micro-holes morphology on Ti3C2 enhances the specific surface area and increases the channels for oxygen, enabling full oxidation between layers and generating more TiO2 and more in-situ generated Ti3C2–TiO2 interfaces, which is conducive to TiO2 distribution and uniformity and provides more active sites. This hydrothermal method using tiny solvents can also produce porous morphology in other MXene materials (such as NbC), and photocatalysts with the special morphology will have a broader application prospect. Moreover, a fine interface connection between Ti3C2 and the in-situ grown TiO2 and the lower work function of Ti3C2 achieve an efficient electron-hole transfer. The hydrogen production performance of the Ti3C2–TiO2 photocatalyst prepared by this simple hydrothermal method has been greatly improved, which is up to 7.28 mmol/h/g with 3 wt% Pt and is 109 times and 7 times the Ti3C2–TiO2 catalyst with no holes and P25, respectively.

Preparation of Antioxidative MXene by Deep Eutectic Solvent-Assisted Electrochemical Ultrasonic Composite Exfoliation and Its Application in Flexible Solid-State Supercapacitors

In this work, we achieved a novel preparation of Ti3C2 MXene (MXene–DES) with few layers and a high degree of hydroxylation by a deep eutectic solvent (DES)-assisted electrochemical ultrasonic composite exfoliation method which is easy to scale up. The electrochemical process used a mixture of low-cost DES (choline chloride–urea) and water as the electrolyte, in which DES acts as a triple role of intercalation, interlayer expansion, and anti-oxidation. DES attached to the surface and interlayer of layered Ti3C2 formed an antioxidative protective cover, resulting in the layered Ti3C2 being grafted with hydroxyl functional groups instead of forming TiO2 in water during the entire exfoliation process. The prepared MXene–DES exhibits fewer layers, larger interlayer spacing, higher degree of hydroxylation, and stronger oxidation resistance than the MXene prepared by traditional ultrasound in a nitrogen atmosphere (MXene–N2). The symmetric flexible solid-state supercapacitor based on an activated carbon electrode and the composite gel polymer electrolyte composed of MXene–DES, DES, and polyvinyl alcohol exhibits good mechanical properties, a wide voltage window of 2.3 V, and a high specific capacitance of 133.7 F·g–1 (0.1 A·g–1). Our strategy paved a simple, low-cost, and relatively environmentally friendly way to the scalable preparation and application of antioxidative high-quality MXene.

Sand-Fixation Model for Interface Engineering of Layered Titania and N/O-Doped Carbon Composites to Enhance Potassium/Sodium Storage.

Layered titania (L-TiO2 ) holds great potential for potassium-ion batteries (PIBs) and sodium-ion batteries (SIBs) due to their high specific capacity. Synthesizing L-TiO2 functional materials for high-capacity and long cyclability battery remains challenging due to the unstable and poor conductivity of bare L-TiO2 . In nature, plant growth can stabilize land by preventing sands from dispersing following desertification. Inspired by nature's "sand-fixation model," Al3+ "seeds" are in situ grown on layered Ti3 C2 Tx "land." Subsequently, NH2 -MIL-101(Al) "plants" with Al as metal nodes are grown on the Ti3 C2 Tx "land" by self-assembly. After annealing and etching processes (similar to desertification), NH2 -MIL-101(Al) is transformed into interconnected N/O-doped carbon (MOF-NOC), which not only acts as a plant-like function to prevent the pulverization of L-TiO2 transformed from Ti3 C2 Tx but also improves the conductivity and stability of MOF-NOC@L-TiO2 . Al species are selected as seeds to improve interfacial compatibility and form intimate interface heterojunction. Systematic ex situ analysis discloses that the ions storage mechanism can be endowed by mixed contribution of non-Faradaic and Faradaic capacitance. Consequently, the MOF-NOC@L-TiO2 electrodes exhibit high interfacial capacitive charge storage and outstanding cycling performance. The interface engineering strategy inspired by "sand-fixation model" provides a reference for designing stable layered composites.

Facile synthesis of Ti

The layered Ti3C2 was successfully fabricated by etching the Al layer of Ti3AlC2 with the assistance of trifluoroacetic acid (TFA). By controlling the reaction time, the residual Ti3AlC2 phase in the Ti3C2 materials can be well removed by the TFA and the thickness of single Ti3C2 layer is ~10 nm. The absorption activity of the samples were also evaluated by adsorbing Congo red (CR) in the aqueous solution. The layered Ti3C2 exhibits much better absorption performance than that of pristine Ti3AlC2 and the maximum adsorption amount of CR is up to 351 mg g−1. This work develops a novel strategy to synthesize layered Ti3C2 without using the corrosive solvent.

Mxene Ti3C2 generated TiO2 nanoparticles in situ and uniformly embedded in rGO sheets as high stable anodes for potassium ion batteries

Ti3C2/TiO2/rGO nanosheets were synthesized as anode materials for potassium ion batteries (KIBs) using modified Hummers, freeze drying, and thermal reduction in this paper. Layered Ti3C2 /TiO2/rGO nanosheets were synthesized by in-situ formation of rGO and TiO2 nanoparticles between Ti3C2 layers. As one of the most important members of MXenes family, Ti3C2 exhibits unique electronic characteristics, high specific surface area, strong electrical conductivity and chemically active surface, which can enhance electrode capacity. There are three ways to increase electrode conductivity and capacity: Firstly, rGO is applied as the substrate for the inlaying of TiO2 and Ti3C2 nanoparticles and nanosheets. Secondly, rGO may also buffer electrode volume changes during charging and discharging processes. In addition, the enormous surface area of rGO makes Ti3C2 and TiO2 nanoparticles dispersion well, and Ti3C2 and TiO2 nanoparticles can well separate rGO nanoparticles and prevent them from stacking up again. The synergistic effect of the three can efficiently relieve the stress and provide a rapid transport pathway between electrons and ions. The flake structure of Ti3C2/TiO2/rGO is advantageous to the stability of SEI film, which makes the material maintain good activity during charge and discharge process, and significantly increases its electrochemical performance. Therefore, Ti3C2/TiO2/rGO electrode has a high reversible capacity of 349.2 mAhg−1 after 200 cycles of 100 mAg−1 current, and a high stable capacity of 229.3 mAhg−1 after 500 cycles of 500 mAg−1 current, and has exceptional rate performance. The structure of Ti3C2/TiO2/rGO composite remains stable after 500 cycles, and no agglomeration occurs. The detailed reaction mechanism of Ti3C2/TiO2/rGO electrode as KIBs anode was analyzed by SEM, XRD, Raman, TGA, FT-IR, BET, TEM, XPS, EDS, CV, EX-situ XRD, ex-situ TEM, and so on. Therefore, it can be concluded that the Ti3C2/TiO2/rGO composite is an appropriate anode material for KIBs.

Directed Stabilization by Air-Milling and Catalyzed Decomposition by Layered Titanium Carbide Toward Low-Temperature and High-Capacity Hydrogen Storage of Aluminum Hydride.

AlH3 is a metastable hydride with a theoretical hydrogen capacity of 10.01 wt % and is very easy to decompose during ball milling especially in the presence of many catalysts, which will lead to the attenuation of the available hydrogen capacity. In this work, AlH3 was ball milled in air (called "air-milling") with layered Ti3C2 to prepare a Ti3C2-catalyzed AlH3 hydrogen storage material. Such air-milled and Ti3C2-catalyzed AlH3 possesses excellent hydrogen storage performances, with a low initial decomposition temperature of just 61 °C and a high hydrogen release capacity of 8.1 wt %. In addition, 6.9 wt % of hydrogen can be released within 20 min at constantly 100 °C, with a low activation energy as low as 40 kJ mol-1. Air-milling will lead to the formation of an Al2O3 oxide layer on the AlH3 particles, which will prevent continuous decomposition of AlH3 when milling with active layered Ti3C2. The layered Ti3C2 will grip on and intrude into the AlH3 particle oxide layers and then catalyze the decomposition of AlH3 during heating. The strategy employing air-milling as a synthesis method and utilizing layered Ti3C2 as a catalyst in this work can solve the key issue of severe decomposition during ball milling with catalysts economically and conveniently and thus achieve both high-capacity and low-temperature hydrogen storage of AlH3. This air-milling method is also effective for other active catalysts toward both reducing the decomposition temperature and increasing the available hydrogen capacity of AlH3.

Anomalous increase in specific capacitance in MXene during galvanostatic cycling studies

Layered Ti3C2 is attracting much attention as a promising electrode material for energy storage devices due to its excellent electrical conductivity and electrochemical properties due to its surface functional groups. Though various methods have been used to etch Ti3AlC2, the energy storage performance of Ti3C2 mainly depends on exfoliation of aluminium, surface functional groups and intercalation of potassium. Hence, the optimization of Ti3AlC2 etching process has been done by hydrothermal, stirring, and ultra-sonication methods which exhibits a different specific capacitance of 8.7 F g−1, 23.75 F g-1, and 141.45 F g−1 respectively in 3 M KOH electrolyte at 2 mA constant current galvanostatic charge/discharge (GCD) analysis even though same etching time and quantity of MAX materials used. Surprisingly, all the samples show an increased specific capacitance up to 2000th cycles and a maximum value of around 170 % is reached and this value is maintained until 5000 charge-discharge cycle at 10 mA by GCD analysis. These electrochemical differences are investigated in terms TiAl bond termination and formation of O-Ti-O bonds due to the removal by Al during etching process. It is found from XPS analysis that -OH surface termination has occurred with F desorption and the interaction of K+ ion has increased the interlayer space between the individual layers. Moreover, the material has been phase transformed from Ti3C2 to TiO2/Ti3C2 hybrid crystal structure during the cycling stability test. The high dipole moment in TiO2/Ti3C2 hybrid structure due to the decreased work function has increased the specific capacitance of MXene electrode material. To the best of the authors' knowledge, this has not been observed previously and reported.

Hierarchical architecture of two-dimensional Ti3C2 nanosheets@Metal-Organic framework derivatives as anode for hybrid li-ion capacitors

Two-dimensional (2D) layered metal carbides materials called MXenes (e.g., Ti3C2) are significantly attentioned as electrode material for lithium-ion capacitors (LICs) because of its large surface-to-volume ratio and ultra-high electronic conductivity. Whereas, as anode electrode material, the performance and application prospects of Ti3C2 are severely restricted to its lower theoretical capacity. In this work, a straightforward and effective strategy to surmount the restrictions was developed to combine layered Ti3C2 nanosheets with dual Co/Zn metal–organic framework (MOF) polyhedrons derivatives through electrostatic assembly. Co3O4/ZnO polyhedrons could prevent the stacking of Ti3C2 nanosheets and provide prominent lithium storage capacity. Furthermore, the advanced structure of Ti3C2@Co3O4/ZnO as anode material could provide short Li+ paths, large electrolyte channels and excellent structural stability to enhance the electrochemical performance for LICs. As a result, the prepared Ti3C2@Co3O4/ZnO composite exhibited a specific capacity of 585.7 mAh/g at 0.1 A/g, and the electrode still delivered a capacity of 229 mAh/g at 2 A/g after 1000 cycles with 93% capacity retention in lithium-ion half cell. In addition, by assembling with activated carbon (AC) as cathode and Ti3C2@Co3O4/ZnO as anode, the LIC revealed an ultra-high energy density of 196.8 Wh/kg at a power density of 174.9 W/kg, and delivered a high energy output of 87.5 Wh/kg even at a power density of 3500 W/kg. And its capacitance retention reaches 75% after 6000 cycles at 2 A/g. The advanced structure, handy preparation, and outstanding performance of layered carbon-based material Ti3C2@hollow polyhedrons composite might provide promising applications in LICs.

Catalytic effect of highly dispersed ultrafine Ru nanoparticles on a TiO2-Ti3C2 support: Hydrolysis of sodium borohydride for H2 generation

To improve the utilization rate of the precious metal, ruthenium, TiO2 nanospheres containing oxygen vacancies are grown on the surface of layered Ti3C2, and superfine Ru nanoparticles are fixed on the surface of TiO2 nanospheres via hydrogen reduction of a Ru precursor. The presence of titanium in a low oxidation state is verified by X-ray photoelectron spectroscopy, thus confirming the existence of oxygen vacancies. Spherical aberration transmission electron microscopy studies indicate the dispersion of uniform Ru nanoparticles (average diameter: ~2 nm) on TiO2, and the existence of a part of Ru in the form of single atoms. The catalyst with 0.33 wt% Ru loading exhibits the best catalytic performance in the hydrolysis of NaBH4 (NaBH4 hydrolysis rate at 303 K is 60 L·min−1·gRu−1). Further, the catalyst performs well even after five cycles of use.

Trimetal NiCoMn sulfides cooperated with two-dimensional Ti3C2 for high performance hybrid supercapacitor

Transition trimetallic sulfide NiCoMn–S attracts great attention due to its high specific capacity for hybrid supercapacitors, as well as Ti3C2 is considered essentially as a potential new electrode material with iconic two-dimensional layered structure and excellent conductivity. Herein, NiCoMn–S nanoparticles are composited with two-dimensional layered Ti3C2 via simple one-step hydrothermal method, which is first applied as positive electrode in hybrid supercapacitors (HSCs). A large number of NiCoMn–S nanoparticles distribute on the surface of Ti3C2 and even insert into the Ti3C2 layers, providing abundant electrochemical active sites for redox reaction and enhancing the mechanical stability for composites. Moreover, the NiCoMn–S/Ti3C2 composites show lower charge-transfer resistance than pure NiCoMn–S, illustrating that the two-dimensional layered structure of Ti3C2 improve the conductivity and supply additional electronic channels for ion transportation. The NiCoMn–S/Ti3C2-3.4% delivers a specific capacity of 347.1 ​C ​g−1 at a specific density of 1 ​A ​g−1, which is 28% higher than that of pure NiCoMn–S (270.2 ​C ​g−1 at 1 ​A ​g−1). Finally, a hybrid supercapacitor (HSC) is assembled by using NiCoMn–S/Ti3C2-3.4% as positive electrode and RGO as negative electrode, realizing a specific capacity of 164.3 ​C ​g−1 at 1 ​A ​g−1 and high specific energy of 16.2 ​Wh kg−1 at a specific power of 15 ​kW ​kg−1.

Role of Reactive Oxygen Species in the Toxicity of Two-Dimensional Nanomaterials: A Study on Layered Ti3c2 Mxenes

Role of Reactive Oxygen Species in the Toxicity of Two-Dimensional Nanomaterials: A Study on Layered Ti3c2 Mxenes

First-principle study on catalytic activity of functionalized Ti3C2 MXene as cathode catalyst for Li–O2 batteries

Two-dimensional layered Ti3C2, one representative MXene, is notable as promising cathode catalyst for rechargeable lithium-oxygen (Li–O2) batteries. Using first-principles calculations, we construct cathode electrochemical interface catalytic model to simulate the structural evolution during discharging and charging processes, and the calculated ORR, OER and TOT overpotentials are used to quantitatively assess the catalytic activity of Ti3C2 MXene with and without O, F and OH functional groups. Interestingly, we find that the catalytic activity follows such a trend: Ti3C2O2>Ti3C2F2>Ti3C2(OH)2>Ti3C2, which suggests that O-terminated Ti3C2 MXene has great advantages and potentiality for catalyzing ORR and OER in Li–O2 batteries. This is caused by Ti3C2O2 surface shows stronger oxidation capability toward O22− compared to Ti3C2F2, Ti3C2(OH)2 and Ti3C2. The present study may provide a guideline to accelerate ORR and OER reactions of Ti3C2 MXene as cathode catalyst in Li–O2 batteries, with O-terminated group being taken into consideration.

Edge-rich MoS2 nanosheets anchored on layered Ti3C2 MXene for highly efficient and rapid catalytic reduction of 4-nitrophenol and methylene blue

In this work, we report a simple one-step hydrothermal synthesis strategy for depositing edge-rich MoS2 nanosheets on conductive layered Ti3C2 MXene, and demonstrate the formed MoS2/Ti3C2 heterostructure has significant active site exposure and effective charge carrier flow. The resulting MoS2/Ti3C2 exhibits enhanced activity and excellent stability for the catalytic reduction of 4-nitrophenol (4-NP). The optimal MoS2/Ti3C2 catalyst displays a high pseudo-first-order rate constant of 0.61 min−1, a conversion efficiency of 96.2% within 5 min and almost unchanged activity after six consecutive reaction cycles, which is better than the pristine MoS2 nanosheets. Moreover, the MoS2/Ti3C2 catalyst achieves a pseudo-first-order rate constant as high as 0.779 min−1 for the catalytic reduction of methylene blue (MB). This study opens up new opportunities for the design and development of cost-effective, efficient and reusable alternatives to noble metal catalysts based on molybdenum disulfide for environmental applications.

Layered Ti3C2 MXene and silver co-modified g-C3N4 with enhanced visible light-driven photocatalytic activity

Novel Ag/g-C3N4/Ti3C2 heterojunction (ACN/TC) was synthesized via one-step calcining the mixture of Ag+-melamine superamolecule and Ti3C2. With robust interfacial contact of ACN/TC heterojunction, the introduction of Ag nanoparticles could induce localized surface plasmon resonance and improve the visible light responsivity. Besides, layered Ti3C2 was served as electron sink and co-catalyst to provide rapid charges transfer channel and enhance O2 adsorption, thereby accelerating the separation of photogenerated charges and production of radicals. The optimized ternary heterojunction (ACN/TC-15) exhibited that the photocatalytic removal rate of Rhodamine B (RhB) and Tetracycline hydrochloride (TC) reached 99.2% and 92.1% under visible light (λ > 420 nm) irradiation, respectively. Besides, extending to λ > 510 nm light irradiation, the removal rate of RhB and TC still 85.6% and 79.5%, respectively. During the TC degradation, the superoxide radical (·O2−) was determined as the main oxidative species. Besides, the possible degradation pathway of TC was proposed. This work not only showed a simplified method for the preparation of Ag/g-C3N4/Ti3C2 composite, but also provided insights into Ti3C2 MXene as co-catalyst to improve the photocatalytic degradation of organic pollutants.

Integrated Co4MnFe3/Ti3C2: Componential and Structural Engineering toward Boosting Electrocatalytic Oxygen Evolution

Compared with traditional two-dimensional layered materials, MXene with metal-like conductivity has excellent chemical reaction activity and hydrophilicity, which can be used as ideal substrate materials. Nanocomposites with the non-noble metal based on MXene have important application prospects in the field of electrocatalytic decomposition of water. In this study, Co4MnFe3/Ti3C2 has been successfully synthesized only by the one-step method and prepared using ultrathin two-dimensional layered Ti3C2 as substrate materials, which is much more convenient than most electrocatalyst hybridization. The hybrid exhibits excellent electrochemical performance in alkaline media with an overpotential of 263 mV and Tafel slope of 26.3 mV·dec–1, which is much lower than that of its pure Co4MnFe3 counterparts and RuO2 catalyst in alkaline medium. When the current density reaches 10 mA/cm2, excellent long-range stability is displayed. Meanwhile, a fast reaction kinetics can also be obtained. Furthermore, density functional theory calculations reveal that, due to electron interactions and d-band center of metals, the enhanced density of states in the vicinity of the Fermi level has great influence on the oxygen evolution reaction property of the electrocatalyst via adjusting the adsorption strength of intermediates, which can improve the electrocatalytic performance of the hybrid. More importantly, this work provides a new approach for the electrolytic water oxygen evolution reaction of MXene-based catalysts in alkaline media and shed light on the exploration of advanced electrocatalysts for renewable energy conversion and storage systems.

Enhanced photocatalytic activity of accordion-like layered Ti3C2 (MXene) coupled with Fe-modified decahedral anatase particles exposing {1 0 1} and {0 0 1} facets

New composites consisting of decahedral anatase particles exposing {001} and {101} facets coupled with accordion-like layered Ti3C2 with boosted photocatalytic activity towards phenol and carbamazepine degradation were investigated. The photocatalysts were characterized with X-ray diffraction (XRD), diffuse reflectance spectroscopy (DR/UV–Vis), Brunauer-Emmett-Teller (BET) specific surface area, Raman spectroscopy, scanning electron microscopy (SEM), electron paramagnetic resonance (EPR) spectroscopy, emission spectroscopy, luminescence decay analysis, electrochemical impedance spectroscopy (EIS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and electrophoretic mobility measurements. The effect of hydrothermal reaction parameters on physicochemical, structural, and photocatalytic properties was studied. In all photodegradation processes, ortho-hydroxyphenol and para-hydroxyphenol were detected as the first intermediates of phenol decomposition. For the TiO2/Ti3C2(140,12) sample containing VTi, a higher concentration of para-hydroxyphenol than ortho-hydroxyphenol was observed, whereas for sample TiO2/Ti3C2(220,24) higher concentration of ortho-hydroxyphenol was noticed. The formation of surface heterojunction between {101} and {001} facets of decahedral anatase particles grown on Ti3C2 surface led to improved photoelectron transfer and enhanced photocatalytic activity towards degradation of carbamazepine - non-biodegradable and susceptible to bioaccumulation in living organisms commonly used pharmaceutical agent. Moreover, modification of TiO2/Ti3C2 surface with iron by magnetron sputtering deposition markedly improved photocatalytic activity in carbamazepine decomposition, with nearly 100% degradation in 60 min of irradiation under simulated solar light.