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Hydrazine is considered a powerful reducing agent and catalyst, showing diverse applications in agricultural industries, toxic degradation research, and wastewater management. Additionally, hydrazine can trigger some specific reactions when combined with suitable oxidants. Due to its highly polar nature, hydrazine can easily dissolve in alcohol, water, and various other polar solvents. Therefore, it can be extensively utilized in different areas of application and industries such as rocketry and various chemical applications. Despite its beneficial properties, hydrazine is unstable, posing significant risk due to its highly toxic nature. It is extremely hazardous to both human health and the environment. It can cause various illnesses and symptoms such as dizziness, temporary blindness, damage to the central nervous system, and even death when inhaled in sufficient quantities. Therefore, it is highly important to monitor the level of hydrazine to prevent its toxic and hazardous effects on human beings and the environment. In the present study, we discuss the simple fabrication of a disposable cost-effective and eco-friendly hydrazine sensor. We used a screen-printed carbon electrode, i.e., SPCE, as a base for the construction of a hydrazine sensor. The Ti3AlC2 MAX has been used as a suitable and efficient electrode material for the fabrication of disposable hydrazine sensors. We modified the active surface of the SPCE using a drop-casting approach. The resulting Ti3AlC2 MAX modified SPCE (Ti3AlC2@SPCE) has been utilized as an efficient and low-cost hydrazine sensor. Cyclic voltammetry, i.e., CV, and linear sweep voltammetry, viz., LSV, was employed as a sensing technique in this study. The optimization of pH and electrode material loading was conducted. The Ti3AlC2@SPCE exhibited excellent sensing performance toward hydrazine oxidation. A reasonable detection limit (0.01 µM) was achieved for hydrazine sensing. The fabricated sensor also demonstrated a reasonable linear range of 1–50 µM. This work provides the design and fabrication of simple disposable Ti3AlC2@SPCE as a suitable electrode for the determination of hydrazine using LSV technology. [ABSTRACT FROM AUTHOR]

The MAX phase is a material with excellent electrical and thermal conductivity and thermal shock and oxidation resistance owing to its metallike bonding properties. The impurities in the Ti3AlC2 MAX phase must be controlled because the oxides and TiC derived from the synthesis process remain in MXene and markedly affect the electrical conductivity and chemical stability. This study investigated whether the Ti3AlC2 MAX phase can be synthesized from titanium powder prepared from low‐cost titanium scrap by hydrogenation–dehydrogenation (HDH) and deoxidation in the solid‐state (DOSS) processes. Almost single‐phase Ti3AlC2 MAX phase was obtained by synthesis at 1450°C for 5 h. The oxygen concentrations of the HDH‐MAX and DOSS‐MAX powders (25–45 μm) were 7215 and 3875 ppm, respectively. Oxygen reduction of titanium powder through DOSS can help improve the purity of Ti3AlC2 MAX phase by minimizing the imbalance in the stoichiometric ratio during synthesis. The HDH‐MAX and DOSS‐MAX powders prepared from titanium scrap displayed a higher Ti3AlC2 phase fraction and lower oxygen concentration than those of commercial Ti3AlC2 MAX phase powders. This cost reduction and purity improvement will increase the accessibility of the Ti3AlC2 MAX phase, supporting further research into its applications. [ABSTRACT FROM AUTHOR]

MAX phase, as a group of layered ternary carbides and nitrides exhibiting combined properties of metallic and ceramic materials, attracts increasing interest because they own exceptionally chemical, physical, electrical, thermal, and mechanical properties. In the present paper, a novel Ti3AlC2-based green part was manufactured by extrusion-based fused filament fabrication (FFF) and 3D printing technologies. The morphology, thermal/electrical conductivity, thermal stability, electromagnetic interference (EMI) shielding effectiveness (SE), and mechanical properties of Ti3AlC2/binder with the volume ratio of 1:1 were investigated. The tensile and compressive strengths and elongation are measured to be 8.29 MPa and 18.20%, 44.90 MPa and 33.76%, respectively. The morphology of the filament reveals that Ti3AlC2 powders are well bonded by the thermoplastic binder. More importantly, the composite shows good thermal and electrical conductivities together with the excellent EMI shielding effectiveness, which is of great potential in the practical applications as conductor, heat dissipating, anti-static, and EMI shielding materials. The successful fabrication of Ti3AlC2-based composites via FFF-based 3D printing technology is beneficial to develop other MAX phase products with complex geometries and additional functionalities. [ABSTRACT FROM AUTHOR]

Hydrazine is considered a powerful reducing agent and catalyst, showing diverse applications in agricultural industries, toxic degradation research, and wastewater management. Additionally, hydrazine can trigger some specific reactions when combined with suitable oxidants. Due to its highly polar nature, hydrazine can easily dissolve in alcohol, water, and various other polar solvents. Therefore, it can be extensively utilized in different areas of application and industries such as rocketry and various chemical applications. Despite its beneficial properties, hydrazine is unstable, posing significant risk due to its highly toxic nature. It is extremely hazardous to both human health and the environment. It can cause various illnesses and symptoms such as dizziness, temporary blindness, damage to the central nervous system, and even death when inhaled in sufficient quantities. Therefore, it is highly important to monitor the level of hydrazine to prevent its toxic and hazardous effects on human beings and the environment. In the present study, we discuss the simple fabrication of a disposable cost-effective and eco-friendly hydrazine sensor. We used a screen-printed carbon electrode, i.e., SPCE, as a base for the construction of a hydrazine sensor. The Ti3AlC2 MAX has been used as a suitable and efficient electrode material for the fabrication of disposable hydrazine sensors. We modified the active surface of the SPCE using a drop-casting approach. The resulting Ti3AlC2 MAX modified SPCE (Ti3AlC2@SPCE) has been utilized as an efficient and low-cost hydrazine sensor. Cyclic voltammetry, i.e., CV, and linear sweep voltammetry, viz., LSV, was employed as a sensing technique in this study. The optimization of pH and electrode material loading was conducted. The Ti3AlC2@SPCE exhibited excellent sensing performance toward hydrazine oxidation. A reasonable detection limit (0.01 µM) was achieved for hydrazine sensing. The fabricated sensor also demonstrated a reasonable linear range of 1–50 µM. This work provides the design and fabrication of simple disposable Ti3AlC2@SPCE as a suitable electrode for the determination of hydrazine using LSV technology.

[Display omitted] • A Ti-Al-C MAX phase (Ti 3 AlC 2) is used to recover gold from acidic solutions. • High gold extraction capacity (>6000 mg/g) is achieved at pH < 1. • High selectivity for gold is observed in the presence of interfering metal ions. • Gold recovery is likely to proceed via a reduction reaction similar to cementation. • High purity gold (92 mass%) is recovered without any posttreatment. Given the scarcity of natural gold sources and associated mining challenges, the recovery of gold from secondary sources, such as electronic equipment waste (e-waste), becomes imperative. E-waste is typically treated with aqua regia to obtain highly acidic gold-containing solutions, which are subsequently processed by various methods to recover gold. Gold recovery materials offer numerous benefits but often exhibit insufficient selectivity, efficiency, and cost-effectiveness. To address this problem, we herein used a nonmodified pristine Ti-Al-C MAX phase (Ti 3 AlC 2) to realize the one-pot room-temperature recovery of gold from highly acidic solutions (pH < 1) in the form of easily collectable bulky ball-shaped Au0 aggregates. High gold selectivity (K d = 2.03 × 106 mL/g) and extraction efficiency (∼99 %) were observed even in the presence of interfering metal ions (Pd2+, Pt4+, Co2+, Ni2+, Cu2+, Zn2+), and the maximum gold extraction capacity (>6000 mg/g) surpassed that of previously reported gold recovery materials. The recovered gold was highly pure (>90 mass%) and contained minimal amounts of the original MAX phase, which obviated the need for intensive postpurification. The results of instrumental analyses suggested that gold recovery relied on electron transfer, similar to cementation, and primarily involved the reduction of solution-phase Au3+ to Au0 via electron transfer from the Ti and Al of Ti 3 AlC 2. Thus, our work demonstrates the significant potential of pristine Ti 3 AlC 2 for the energy-efficient recovery of gold from highly acidic solutions and paves the way for the efficient valorization of e-waste. [ABSTRACT FROM AUTHOR]

In this research, we propound a facile and efficient strategy for the synthesis of carbide-derived nanocarbon structures (CDCs) by electrochemical etching of Ti 3 AlC 2 MAX phase in hydrofluoric acid solutions. Al, Ti and C powders were milled and used to synthesize Ti 3 AlC 2 MAX phase powders and then, the obtained powders were sintered using spark plasma sintering (SPS) method. The obtained bulk sample was then electrochemically etched for 2 h at 5v and 20v and concentrations of 20 wt% and 10 wt% hydrofluoric acid to obtain CDC. The results showed that titanium and aluminum were extracted from the Ti 3 AlC 2 MAX phase structure by electrochemical etching in HF solution. Structural and morphological studies of CDCs obtained by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and scanning field emission electron microscopy (FESEM) were performed. Examination of SEM and FESEM illustrations showed that the structure of CDCs consisted of graphene nanosheets. The distance and number of graphene layers were obtained according to the XRD results and the I D /I G value was assessment to be 0.81 according to Raman spectroscopy, demonstration plenty of oxygen functional groups on the surface of graphene sheets. Also, EDS analysis and XRD and Raman spectroscopy outcomes were in well agreement with SEM and FESEM images. The results were shown, at constant voltage, increasing the concentration has led to the production of more CDC nanostructures. At a constant concentration with increasing voltage amorphous carbon was formed instead of graphite. Eventually it was found that by changing the voltage and concentration of the solution, both titanium and aluminum were still extracted and CDC was formed. [ABSTRACT FROM AUTHOR]

• Ti 3 AlC 2 were prepared by in-situ reaction of Ti-Al-C system by powder metallurgy. • The proportion of raw powders has the greatest influence on purity of the sample. • The Ti 3 Al 1.2 C 2 -1300-60 sample has the highest purity 97.23 wt% of Ti 3 AlC 2. • The Ti 3 AlC 2 prepared by this work has better comprehensive mechanical properties. In order to clarify the effects of the proportion of raw powders, heating temperature and holding time on the purity and properties of MAX phase Ti 3 AlC 2 , powder mixtures of Ti, Al and C powder with different ratio were prepared by planetary ball mill and heated under different conditions by spark plasma sintering. The microstructures and phase structures of the as-synthesized samples were characterized, the correlation between the mechanical properties and microstructure and fracture mechanism were investigated systematically. The results show that with the proportion of raw powders Ti:Al:C = 3:1.2:2, the sample heated at 1300 °C for 60 min has the highest purity 97.23 wt% of MAX phase. It has a compact and uniform lath-like structure with the length-thickness ratios of 3–5 and excellent comprehensive mechanical properties: the Vickers hardness, bending strength and fracture toughness are 5.26 GPa, 500 MPa and 7.35 MPa∙m1/2, respectively. The experimental results show that among the three factors, the proportion of raw powders has the greatest influence on purity of Ti 3 AlC 2 phase, followed by heating temperature and holding time. The fracture morphologies of the tested samples demonstrate that under the action of external force, extrusion and kink occurred in the layered structures of Ti 3 AlC 2 phase. These two forms of energy dissipation lead to the bending strength and fracture toughness of Ti 3 AlC 2 are higher than that of traditional ceramics. [ABSTRACT FROM AUTHOR]

A Ti3AlC2 MAX phase-based saturable absorber (SA) is successfully demonstrated to induce passive Q-switching in an erbium-doped fiber laser (EDFL) at the $1.5~\mu \text{m}$ region. The Ti3AlC2-PVA film is fabricated using the solution casting method and incorporated into the laser cavity which uses a 0.89 m long erbium doped fiber as the gain medium. Stable and self-starting Q-switched laser pulses are observed above a threshold pump power of 87.81 mW at a central wavelength of 1567.4 nm. The repetition rate is observed to increase from 24.07 kHz to 46.3 kHz, while the corresponding pulse width decreases from $5.0~\mu \text{s}$ to $0.99~\mu \text{s}$ over a pump power range of 108.9 mW to 244.5 mW. At the maximum pump power of 244.5 mW, the highest pulse energy of 102.7 nJ and the maximum output power of 4.75 mW are obtained. These findings demonstrated the feasibility of the Ti3AlC2 MAX phase as an SA material with significant promise for photonic applications. This is also, to the best knowledge of the authors, the first report of a Ti3AlC2 MAX phase-based SA for inducing passive Q-switching in an EDFL. [ABSTRACT FROM AUTHOR]

The reported study involves the synthesis of high purity layered ternary carbide Ti 3 AlC 2 MAX phase material by mixing the TiH 2 , Al and TiC powders in a planetary ball mill followed by two step pressureless sintering in flowing Argon (Ar) atmosphere. XRD and Raman analysis confirms the presence of Ti 3 AlC 2 phase without impurities of Al 2 O 3 and TiC. The morphology studies using SEM confirms the lamellar structure of Ti 3 AlC 2 and EDS measurements shows atomic percentage of Ti, Al and C are in compliance with the XRD phase analysis. X-ray Photoelectron spectroscopy investigations confirm the Ti–C bond. Core level XPS data of Al2p peak show a negative shift indicating electrostatic bonding of Al in Ti 3 AlC 2. Ti2p and C1s core level spectra show the bonding of M n+1 X n i.e TiC bond. TG-DSC results revealed approximately 7% increase in weight. Ti 3 AlC 2 phase follows an endothermic pattern and does not undergo decomposition upto 1400 °C in vacuum environment. From XRD analysis at different temperatures, it was seen that Al 2 O 3 and TiC x peaks started to form along with Ti 3 AlC 2 at 1000 °C because of selective oxidation of Al into Al 2 O 3. Thus, this study provides a beneficial approach to synthesis of high-purity Ti 3 AlC 2 materials and understanding the thermal behaviour of Ti 3 AlC 2 for high temperature applications. • High Purity single phase Ti 3 AlC 2 was synthesised by Pressureless Sintering using commercial powders i.e. TiH 2 , Al and TiC powders. • XPS investigations revealed a negative shift than the metallic Al signal, indicating electrostatic bonding. • The DSC analysis showed the selective oxidation of Al resulting in the formation of alumina along with Ti 3 AlC 2. • High Temperature X-ray diffraction analysis reveals the formation of Al 2 O 3 at 1000 °C. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ti 3 AlC 2 MAX phase with purity of 99.0% was synthesized by molten salt method. • Powder is prepared in a vacuum quartz tube without inert gas protection. • Mechanical activation reduces reaction temperature and improves product purity. • Two mechanisms have been proposed. Many methods have been used to synthesize the Ti 3 AlC 2 MAX phase, but obtaining high-purity (>99.0 %) Ti 3 AlC 2 is still a challenge. In this work, nano/submicro-sized Ti 3 AlC 2 powder was prepared using Ti/Al/C elemental powders by the molten salt method in a vacuum quartz tube system. The effects of reaction temperature and dwell time, mechanical activation, the ratio of flux to reactants, and the ratio of Al on the synthesis of Ti 3 AlC 2 were systematically investigated. The results show that Ti 3 AlC 2 powder with a high purity of up to 99.0 % was prepared using ball milled 3Ti/1.1Al/2C mixture as the reaction material, and NaCl-KCl as the molten salt at 1150 °C for 2 h. The reaction mechanisms of Ti 3 AlC 2 in molten salt have been discussed. [ABSTRACT FROM AUTHOR]

The study presents an investigation of irradiation resistance properties of Ti3AlC2 under 500keV He ions irradiation with the doses ranging from 5.0×1016 to 1.0×1018 ionscm−2 at certain temperatures, like room temperature (RT), 300 and 500°C. X-ray diffraction (XRD) and Transmission electron microscopy (TEM) are used to study the evolution of structural damage and the behavior of deposited He ions respectively. XRD analysis reveals that for the highest dose irradiation (∼52dpa at peak), no amorphization occurs. And the structural recovery of Ti3AlC2 is more significant accompanied with the gradual disappearance of the irradiation-induced TiC phase as the temperature rises from RT to 300 and to 500°C with the same dose irradiation. TEM observations show that He bubbles appear in the shapes of sphere, string and platelet but no big bubbles are formed for all irradiations. Moreover, no large cracks form in the sample implanted with the highest helium concentration of ∼6.4×105 appm. [ABSTRACT FROM AUTHOR]

[Display omitted] • Deoxidation was conducted to remove α-Al 2 O 3 inclusions in the Ti 3 AlC 2 powder. • Ti 3 AlC 2 powder without α-Al 2 O 3 inclusion was manufactured. • Ti 2 AlC phase was formed when using the excess Ca. • Ti 2 AlC phase was suppressed when reducing usage of Ca. • Oxygen concentration of the deoxidized Ti 3 AlC 2 powder decreased to 3,400 ppm. This study investigates the decrease in oxygen concentration caused by the removal of α-Al 2 O 3 inclusions in Ti 3 AlC 2 MAX powder. The Ti 3 AlC 2 MAX powder was deoxidized in the solid-state using calcium (Ca) as the reductant under contact and noncontact conditions. The oxygen concentration was decreased by removing the α-Al 2 O 3 inclusions in Ti 3 AlC 2 MAX powder through Ca contact and non-contact deoxidation. In the α-Al 2 O 3 reduction reaction, Al diffusion and excess Ca interactions led to the formation of a Ti 2 AlC phase, which was suppressed by reducing amount of Ca used. Oxygen reduction without any phase change was possible through contact deoxidation at 750 °C for 5 h. The oxygen concentration of deoxidized MAX powder was 9,450 ppm. In the case of noncontact deoxidation, the Ti 2 AlC phase was suppressed by reducing the amount of Ca used to 0.5 g. The oxygen concentration of the deoxidized MAX powder was 3,400 ppm. [ABSTRACT FROM AUTHOR]

• MAX phase coating can be applied for improving BPs properties. • Preparation of nano-Ti 3 AlC 2 coatings. • The ICR of Ti 3 AlC 2 -coated sample is 3.725 mΩ cm2 at 140 N cm−2. • Ti 3 AlC 2 -coatings exhibit the excellent electrochemical corrosion resistance. Conductive ceramic MAX-phase (Ti 3 AlC 2) coated stainless-steel 304 exhibits good corrosion resistance in pH 3 H 2 SO 4 solution containing 2 ppm F− at 70 °C in simulated PEMFC environments. The corrosion current density of the Ti-Al-C films is 0.44 μA·cm-2 were calculated using the potentiodynamic polarization, and the current density during the 24 h potentiostatic polarization test is 0.8 μA·cm-2. The interfacial contact resistance value of the Ti 3 AlC 2 -coated samples is 3.725 mΩ·cm2 at 140 N·cm-2 pressure, which is very low as compared to the bare SS304. [ABSTRACT FROM AUTHOR]