Cu/Cu2O/C nanoparticles and MXene based composite for non-enzymatic glucose sensors.

Copper/Cuprous oxide/Carbon nanoparticles decorated MXene composite was prepared and subsequently examined for its potential application as a non-enzymatic glucose sensor. To carry out this, initially the Cu MOF/MXene composite was synthesised by the hydrothermal method and was annealed in an unreacted environment at different time intervals. During this process, petal like Cu MOF on MXene loses the organic ligands to form a Cu/Cu2O/C based nanoparticles on MXene. Further, an electrode was fabricated with the developed material for understanding the sensing performance by cyclic voltammetry and chronoamperometry in 0.1 M NaOH solution. Results reveal that the highest weight percentage of copper oxide in the composite (15 min of annealed material) shows a higher electro catalytic activity for sensing glucose molecules due to more active sites with good electron transfer ability in the composite. The formed composite exhibits a wide linear range of 0.001-26.5 mM, with a sensitivity of 762.53µAmM-1cm-2(0.001-10.1 mM), and 397.18µAmM-1cm-2(11.2-26.9 mM) and the limit of detection was 0.103µM. In addition to this, the prepared electrode shows a good reusability, repeatability, selectivity with other interferences, stability (93.65% after 30 days of storage), and feasibility of measuring glucose in real samples. This finding reveals that the metal oxide derived from MOF based nanoparticle on the MXene surface will promote the use of non-enzymatic glucose sensors.

Experimental and computational DFT, drift-diffusion studies of cobalt-based hybrid perovskite crystals as absorbers in perovskite solar cells.

The optimised designs of dimethyl ammonium cobalt formate-based perovskite crystals [(CH3)2NH2]Co(HCOO)3 were experimentally synthesized and computationally utilized as absorbers for perovskite solar cells (PSCs). Crystals were grown using solvothermal synthesis. Additive materials (Fe, Ni) are responsible for the growth and suppression of crystals in the micrometre range. Temperature and pressure were altered to obtain optimum growth conditions. Grown crystals were characterized by spectroscopy (XRD, FT-IR, UV-Vis) and optical microscopy. Combined density functional theory (DFT) and drift-diffusion modelling frameworks were simulated. These simulators were used to examine various perovskite absorbers for solar-cell configurations. Field calculations were used to examine the structural stability, band structure, and electronic contribution of the constituent elements in [(CH3)2NH2]Co1-nMn(HCOO)3 (M = Fe, Ni and n = 0, 0.1) as absorber material. Conventional TiO2 and spiro-OMeTAD were used as the electron-transport layer and hole-transport layer, respectively, and Pt was used as a back contact. Comprehensive analysis of the effects of several parameters (layer thickness, series and shunt resistances, temperature, generation-recombination rates, current-voltage density, quantum efficiency) was carried out using simulation. Our proposed strategy may pave the way for further design of new absorber materials for PSCs.

Editorial: Focus on green nanomaterials for a sustainable internet of things.

In the dynamic landscape of the Internet of Things (IoT), where smart devices are reshaping our world, nanomaterials can play a pivotal role in ensuring the IoT's sustainability. These materials are poised to redefine the development of smart devices, not only enabling cost-effective fabrication but also unlocking novel functionalities. As the IoT is set to encompass an astounding number of interconnected devices, the demand for environmentally friendly nanomaterials takes center stage. ThisFocus Issuespotlights cutting-edge research that explores the intersection of nanomaterials and sustainability. The collection delves deep into this critical nexus, encompassing a wide range of topics, from fundamental properties to applications in devices (e.g. sensors, optoelectronic synapses, energy harvesters, memory components, energy storage devices, and batteries), aspects concerning circularity and green synthesis, and an array of materials comprising organic semiconductors, perovskites, quantum dots, nanocellulose, graphene, and two-dimensional semiconductors. Authors not only showcase advancements but also delve into the sustainability profile of these materials, fostering a responsible endeavour toward a green IoT future.

Multi-walled carbon nanotube-based nanobiosensor for the detection of cadmium in water.

Industrial and agricultural processes have led to the prevalence of cadmium in the ecosystem. A successive build-up of cadmium in food and drinking water can result in inadvertent consumption of hazardous concentrations. Such environmental contamination of cadmium can pose a substantial threat to human and animal life. In humans, it is known to cause hypertension, cardiovascular diseases, DNA lesions, inhibition of DNA repair protein or disturb the functioning of lung, liver, prostate and kidney. The development of a reliable method for Cd (II) ions detection would reduce the exposure and complement existing conventional methods. In this study, a DNA based electrochemical method is employed for the detection of Cd (II) ions using ethyl green (EG) and multi-walled carbon nanotube (MWCNT). Glassy carbon electrode (GCE)/MWCNT forms the working electrode for differential pulse voltammetry (DPV) analysis for the detection of Cd (II) ions. The dsDNA is immobilized onto the working electrode. The indicator dye EG, preferably binds to ssDNA and its reduction peak current is noticeably less in the presence of dsDNA. The Cd (II) ions after interacting with dsDNA, unwinds the dsDNA to ssDNA, upon which the EG molecules bind to ssDNAs, giving a higher reduction peak current. The difference in the reduction peak currents in the presence and absence of Cd (II) ions is proportional to its concentration. The linear detection range achieved in this method is 2 nM-10.0 nM with a sensitivity of around 5 nA nM-1 and the limit of detection is 2 nM, which is less than the permissible limit of WHO for human exposure. This study considerably broadens the possible application of multi-walled carbon nanotube modified electrodes as biosensors and holds prospects for the detection of other heavy metals in environmental samples.

NH2-MIL-125(Ti) doped CdS/Graphene composite as electro and photo catalyst in basic medium under light irradiation.

The development of active electrocatalysts and photocatalysts for hydrogen evolution reaction (HER) and for environmental remediation is a huge challenge. Research is still underway on the development of low-cost catalytic materials with appreciable efficiency for HER. In the present study, a composite of metal organic framework (MOF) with CdS and graphene (NH2-MIL-125(Ti)/CdS-graphene) composites were developed with different loadings of graphene material via solvothermal technique. Further the electrocatalytic activity of the synthesized catalysts were investigated for HER and photocatalytic degradation of dye. Results show that the synthesized catalyst with a less amount of graphene was more active. HER results showed a less Tafel slope of 70.8 and 61.9 mVdec-1 with 15.6 mA/cm2 and 15.46 mA/cm2 current densities under light on and off conditions. Further the dye degradation activity of the synthesized catalysts was tested with Rhodamine B dye and results showed that the catalyst showed excellent activity for low weight loading of graphene with a degradation efficiency of 95 % and followed pseudo first order kinetic model. Overall results showed that the synthesized composites are promising for HER and photocatalytic applications.

Crotalaria verrucosa Leaf Extract Mediated Synthesis of Zinc Oxide Nanoparticles: Assessment of Antimicrobial and Anticancer Activity.

In this work, we present an ecofriendly, non-hazardous, green synthesis of zinc oxide nanoparticles (ZnO NPs) by leaf extract of Crotalaria verrucosa (C. verrucosa). Total phenolic content, total flavonoid and total protein contents of C. verrucosa were determined. Further, synthesized ZnO NPs was characterized by UV-visible spectroscopy (UV-vis), X-ray diffractometer (XRD), Fourier transform infra-red (FTIR) Spectra, transmission electron microscope (TEM), and Dynamic light scattering (DLS) analysis. UV-vis shows peak at 375 nm which is unique to ZnO NPs. XRD analysis demonstrates the hexagonal phase structures of ZnO NPs. FTIR spectra demonstrates the molecules and bondings associated with the synthesized ZnO NPs and assures the role of phytochemical compounds of C. verrucosa in reduction and capping of ZnO NPs. TEM image exhibits that the prepared ZnO NPs is hexagonal shaped and in size ranged between 16 to 38 nm which is confirmed by DLS. Thermo-gravimetric analysis (TGA) was performed to determine the thermal stability of biosynthesized nanoparticles during calcination. The prepared ZnO NPs showed significant antibacterial potentiality against Gram-positive (S. aureus) and Gram-negative (Proteus vulgaris, Klebsiella pneumoniae, and Escherichia coli) pathogenic bacteria and SEM image shows the generalized mechanism of action in bacterial cell after NPs internalization. In addition, NPs are also found to be effective against the studied cancer cell lines for which cytotoxicity was assessed using MTT assay and results demonstrate highest growth of inhibition at the concentration of 100 µg/mL with IC50 value at 7.07 µg/mL for HeLa and 6.30 µg/mL for DU145 cell lines, in contrast to positive control (C. verrucosa leaf extract) with IC50 of 22.30 µg/mL on HeLa cells and 15.72 µg/mL on DU145 cells. Also, DAPI staining was performed in order to determine the effect on nuclear material due to ZnO NPs treatment in the studied cell lines taking leaf extract as positive control and untreated negative control for comparison. Cell migration assay was evaluated to determine the direct influence of NPs on metastasis that is potential suppression capacity of NPs to tumor cell migration. Outcome of the synthesized ZnO NPs using C. verrucosa shows antimicrobial activity against studied microbes, also cytotoxicity, apoptotic mediated DNA damage and antiproliferative potentiality in the studied carcinoma cells and hence, can be further used in biomedical, pharmaceutical and food processing industries as an effective antimicrobial and anti-cancerous agent.

Investigation and development of photocathodes using polyaniline Encapsulated Ti3C2Tx MXene nanosheets for dye-sensitized solar cells.

In the current study, polyaniline (PANI) modified two-dimensional Ti3C2Tx MXene composites (PANI-Ti3C2Tx) are exploited as photocathodes in dye-sensitized solar cells (DSSCs). The study revealed that incorporating PANI into Ti3C2Tx improved the material's electrochemical properties, owing to the presence of amino groups in PANI that enhanced the material's electrical conductivity and thereby facilitated more rapid ion transport. In addition, PANI enhanced the surface wettability of Ti3C2Tx, resulting in an increase in the number of electroactive sites. The presence of PANI molecules in the interlayer and on the surface of Ti3C2Tx was confirmed through X-ray diffraction (XRD), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX), and X-ray photoelectron spectroscopy (XPS). Subsequently, electrochemical analysis of the PANI-Ti3C2Tx photocathode or counter electrode (CE) revealed a commendable electrocatalytic activity with the iodide/triiodide electrolyte, a favourable charge transfer kinetics, and a charge transfer resistance as low as platinum. Additionally, at AM 1.5G, the performance of the DSSC constructed using the thermally decomposed Pt-CE was 8.3% when subjected to simulated 1 sun light, whereas the efficiency of the DSSC constructed using the as-prepared composite material was 6.9% under corresponding conditions. PANI-Ti3C2Tx as the photocathode (CE) in a DSSC showed a higher power conversion efficiency (PCE) improvement than PANI CE and Ti3C2Tx CE DSSCs, emphasizing its potent catalytic activity and quick mass transport of electron capability. By capitalizing on the conductivity and electrocatalytic property of the two components, the as-fabricated PANI-Ti3C2Tx photocathode significantly increased the overall PCE of DSSCs. Furthermore, the DSSC utilizing the PANI-Ti3C2Tx CE demonstrated exceptional reproducibility and stability. This underscores its consistently high performance and significant resistance to corrosion in the iodide/triiodide redox electrolyte environment. Overall, these findings show that the PANI-Ti3C2Tx composite has the potential to be a competitive alternative to platinum-based CE materials for the development of DSSCs with exceptional performance.

Fabrication of a free-standing Ti3C2T x -PTh counter electrode via interfacial polymerization for dye-sensitized solar cells.

The current work involves the fabrication of a MXene-Polythiophene (Ti3C2T x -PTh) composite via interfacial polymerization, alongside its deployment as a counter electrode (CE) or photocathode in dye-sensitized solar cells (DSSCs). The structural properties of the synthesized materials were investigated through a comprehensive array of techniques, including X-ray diffraction (XRD), fourier-transform infrared (FT-IR) spectroscopy, high resolution scanning electron microscopy (HRSEM), energy-dispersive X-ray analysis (EDAX), and X-ray photoelectron spectroscopy (XPS). The electrochemical performance, assessed via cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), revealed that the Ti3C2T x -PTh CE exhibits superior electro-catalytic activity, and reduction in charge transfer resistance compared to other individual CEs. These observations are in concordance with the data obtained from Tafel analysis. The incorporation of Ti3C2T x sheets into the composite significantly augmented its catalytic efficacy for triiodide reduction, manifesting in elevated short-circuit photocurrent density and enhanced fill factor metrics. A DSSC utilizing the Ti3C2T x -PTh CE exhibited a power conversion efficiency (PCE) of 5.83%, which stands on par with that of traditional Pt CEs. Thus, the Ti3C2T x -PTh CE material is posited as a viable, cost-efficient alternative to Pt, heralding a new era in the engineering of counter electrodes for the next generation of DSSCs.

The dawn of MXene duo: revolutionizing perovskite solar cells with MXenes through computational and experimental methods.

Integrating MXene into perovskite solar cells (PSCs) has heralded a new era of efficient and stable photovoltaic devices owing to their supreme electrical conductivity, excellent carrier mobility, adjustable surface functional groups, excellent transparency and superior mechanical properties. This review provides a comprehensive overview of the experimental and computational techniques employed in the synthesis, characterization, coating techniques and performance optimization of MXene additive in electrodes, hole transport layer (HTL), electron transport layer (ETL) and perovskite photoactive layer of the perovskite solar cells (PSCs). Experimentally, the synthesis of MXene involves various methods, such as selective etching of MAX phases and subsequent delamination. At the same time, characterization techniques encompass X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy, which elucidate the structural and chemical properties of MXene. Experimental strategies for fabricating PSCs involving MXene include interfacial engineering, charge transport enhancement, and stability improvement. On the computational front, density functional theory calculations, drift-diffusion modelling, and finite element analysis are utilized to understand MXene's electronic structure, its interface with perovskite, and the transport mechanisms within the devices. This review serves as a roadmap for researchers to leverage a diverse array of experimental and computational methods in harnessing the potential of MXene for advanced PSCs.

MXene-Embedded Porous Carbon-Based Cu2O Nanocomposites for Non-Enzymatic Glucose Sensors.

This work explores the use of MXene-embedded porous carbon-based Cu2O nanocomposite (Cu2O/M/AC) as a sensing material for the electrochemical sensing of glucose. The composite was prepared using the coprecipitation method and further analyzed for its morphological and structural characteristics. The highly porous scaffold of activated (porous) carbon facilitated the incorporation of MXene and copper oxide inside the pores and also acted as a medium for charge transfer. In the Cu2O/M/AC composite, MXene and Cu2O influence the sensing parameters, which were confirmed using electrochemical techniques such as cyclic voltammetry, electrochemical impedance spectroscopy, and amperometric analysis. The prepared composite shows two sets of linear ranges for glucose with a limit of detection (LOD) of 1.96 µM. The linear range was found to be 0.004 to 13.3 mM and 15.3 to 28.4 mM, with sensitivity values of 430.3 and 240.5 µA mM-1 cm-2, respectively. These materials suggest that the prepared Cu2O/M/AC nanocomposite can be utilized as a sensing material for non-enzymatic glucose sensors.

CO2 absorption and sequestration as various polymorphs of CaCO3 using sterically hindered amine.

One aspect of the attempt to restrain global warming is the reduction of the levels of atmospheric CO2 produced by fossil fuel power systems. This study attempted to develop a method that reduces CO2 emissions by investigating the absorption of CO2 into sterically hindered amine 2-amino-2-methyl-1-propanol (AMP), the acceleration of the absorption rate by using the enzyme carbonic anhydrase (CA), and the conversion of the absorption product to stable carbonates. CO2 absorbed by AMP is converted via a zwitterion mechanism to bicarbonate species; the presence of these anions was confirmed with (1)H and (13)C NMR spectral analysis. The catalytic efficiency (kcat/Km), CO2 absorption capacities, and enthalpy changes (ΔHabs) of aqueous AMP in the presence or absence of CA were found to be 2.61 × 10(6) or 1.35 × 10(2) M(-1) s(-1), 0.97 or 0.96 mol/mol, and -69 or -67 kJ/mol, respectively. The carbonation of AMP-absorbed CO2 was performed by using various Ca(2+) sources, viz., CaCl2 (CAC), Ca(OOCCH3)2 (CAA), and Ca(OOCCH2CH3)2 (CAP), to obtain various polymorphs of CaCO3. The yields of CaCO3 from the Ca(2+) sources were found in the order CAP > CAA > CAC as a result of the effects of the corresponding anions. CAC produces pure rhombohedral calcite, and CAA and CAP produce the unusual phase transformation of calcite to spherical vaterite crystals. Thus, AMP in combination with CAA and CAP can be used as a CO2 absorbent and buffering agent for the sequestration of CO2 in porous CaCO3.

Nanocellulose-based aerogel electrodes for supercapacitors: A review.

Recently, in response to the challenges related to energy development and environmental issues, extensive efforts are being made towards the development of supercapacitors based on green and sustainable resources. Aerogel electrodes offer high energy/power autonomy, fast charge-discharge rates, and long charge/discharge cycles over composite film electrodes due to their unique structure, ultra-lightness, high porosity, and large specific surface area. Nanocellulose (NC), a sustainable nanomaterial, has gained popularity as a supercapacitor electrode material owing to its remarkable properties such as biodegradability, tunable surface chemistry, ability to develop 3D aerogel structures, etc. This comprehensive review summarizes the research progress on developing NC-based aerogels for supercapacitor applications. First, the fundamentals of NC extraction from cellulose sources and aerogel processing routes are discussed. An attempt is made to correlate the electrochemical performance of NC-based electrodes with their aerogel structures. Finally, challenges and future prospects for the advancement of NC-based aerogels are addressed.

Reduced graphene oxide supported MXene based metal oxide ternary composite electrodes for non-enzymatic glucose sensor applications.

Diagnosis and monitoring of glucose level in human blood has become a prime necessity to avoid health risk and to cater this, a sensor's performance with wide linearity range and high sensitivity is required. This work reports the use of ternary composite viz. MG-Cu2O (rGO supported MXene sheet with Cu2O) for non-enzymatic sensing of glucose. It has been prepared by co-precipitation method and characterized with X-ray powder diffraction, Ultraviolet-visible absorption spectroscopy (UV-Vis), Raman spectroscopy, Field emission scanning electron microscopy, High resolution transmission electron microscopy and Selected area diffraction. These analyses show a cubic structure with spherical shaped Cu2O grown on the MG sheet. Further, the electrocatalytic activity was carried out with MG-Cu2O sensing element by cyclic voltammetry and chronoamperometry technique and compared with M-Cu2O (MXene with Cu2O) composite without graphene oxide. Of these, MG-Cu2O composite was having the high defect density with lower crystalline size of Cu2O, which might enhance the conductivity thereby increasing the electrocatalytic activity towards the oxidation of glucose as compared to M-Cu2O. The prepared MG-Cu2O composite shows a sensitivity of 126.6 µAmM-1 cm-2 with a wide linear range of 0.01to 30 mM, good selectivity, good stability over 30 days and shows a low Relative Standard Deviation (RSD) of 1.7% value towards the sensing of glucose level in human serum. Thus, the aforementioned finding indicates that the prepared sensing electrode is a well suitable candidate for the sensing of glucose level for real time applications.

Development of Cu3N electrocatalyst for hydrogen evolution reaction in alkaline medium.

A wide variety of electrocatalysts has been evolved for hydrogen evolution reaction (HER) and it is reasonable to carry out HER with low cost electrocatalyst and a good efficiency. In this study, Cu3N was synthesized by nitridation of Cu2O and further utilized as an electrocatalyst towards HER. The developed Cu3N electrocatalyst was tested and results showed a low overpotential and moderate Tafel slope value (overpotential: 149.18 mV and Tafel slope 63.28 mV/dec at 10 mA/cm2) in alkaline medium with a charge transfer resistance value as calculated from electrochemical impendence spectroscopy being 1.44 Ω. Further from the experimental results, it was observed that the reaction kinetics was governed by Volmer-Heyrovsky mechanism. Moreover, Cu3N has shown an improved rate of electron transfer and enhanced accessible active sites, due to its structural properties and electrical conductivity. Thus the overall results show an excellent electrochemical performance, leading to a new pathway for the synthesis of low cost electrocatalyst for energy conversion and storage.

Effect of the Graphene- Ni/NiFe2O4 Composite on Bacterial Inhibition Mediated by Protein Degradation.

Recent investigations have demonstrated that nickel ferrite nanoparticles and their derivatives have toxicity effects on bacterial cells. In this study, we have prepared nickel ferrite nanoparticles (Ni/NiFe2O4) and nickel/nickel ferrite graphene oxide (Ni/NiFe2O4-GO) nanocomposite and evaluated their toxic effects on E. coli cells ATCC 25922. The prepared nanomaterials were characterized using X-ray diffraction, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, and vibrating sample magnetometry techniques. The toxicity was evaluated using variations in cell viability, cell morphology, protein degradation, and oxidative stress. Ni/NiFe2O4-GO nanocomposites likewise prompt oxidative stress proved by the age of reactive oxygen species (ROS) and exhaustion of antioxidant glutathione. This is the first report indicating that Ni/NiFe2O4-GO nanocomposite-initiated cell death in E. coli through ROS age and oxidative stress.

Construction of magnetically recoverable ZnS-WO3-CoFe2O4 nanohybrid enriched photocatalyst for the degradation of MB dye under visible light irradiation.

Easily recyclable photocatalysts have received considerable attention for their practical application, in order to address the wastewater treatments. Here, we report efficient and magnetically recyclable ZnS-WO3-CoFe2O4 nanohybrid prepared through wet impregnation method. The photophysical and optical properties of as-prepared photocatalysts was investigated by different spectroscopic techniques. The photocatalytic activity of as synthesized samples were assessed by the photodegradation of methylene blue (MB) dye under visible light irradiation. Amongst, ZnS-WO3-CoFe2O4 nanohybrid exhibit higher photodegradation activity than the other bare and hybrid samples. The enhanced light absorption and lower emission intensity provide the improved photocatalytic activity of ZnS-WO3-CoFe2O4 nanohybrid. The ZnS-WO3-CoFe2O4 nanohybrid exhibit excellent photostability after four consecutive cycles. The ferromagnetic behavior of the hybrid sample using easily recover from the dye solution using an external bar magnet.

In-situ development of metal organic frameworks assisted ZnMgAl layered triple hydroxide 2D/2D hybrid as an efficient photocatalyst for organic dye degradation.

Metal organic framework (MOF) supported layered triple hydroxide (LTH) 2D/2D hybrid material was prepared by a simple hydrothermal method. The photophysical properties of the prepared samples were investigated through a set of analytical methods such as X-ray diffraction, Fourier-transform infrared spectroscopy, field emission scanning electron microscope, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy and mapping. The photocatalytic degradation activity of as prepared 2D/2D MOF-5/LTH hybrid sample was investigated against methylene blue (MB) dye under the UV-visible light irradiation. The degradation efficiency of the MOF-5/LTH hybrid sample was twice a time greater than that of pristine MOF-5, particularly degradation efficiency of the MOF-5, LTH and MOF-5/LTH hybrid samples are 43.3, 57.7 and 98.1% respectively. The Pseudo first order rate and the reusing investigation was further used to study the catalytic activity and stability of the as-synthesized 2D/2D photocatalyst. The observed improvement in the photocatalytic activity of the hybrid samples were owed to enhance visible light absorption, efficient separation and transportation of photoinduced electrons and holes.

Au integrated 2D ZnO heterostructures as robust visible light photocatalysts.

Integration of semiconducting nanostructures with noble metal nanoparticles are turning highly desirable for cost efficient energy and environmental related applications. From this viewpoint, we report on a facile aqueous synthesis of polymer capped gold (Au) nanoparticles on free standing 2D layered structures of zinc oxide (ZnO) to result with ZnO/Au nanocomposites. Concentration of Au nanoparticles were observed to promote the preferential growth of ZnO along the (002) wurtzite plane. The ZnO/Au structures and their morphological dissemination was noted to be of few. This flake like structure was also noted to be greatly influenced by the concentration of Au in the colloidal blend. Optical band edge transformations noted in the absorption spectra across the lower wavelength region and the shift in surface plasmon resonance (SPR) towards the red region of the visible spectrum signify the improved absorptivity of the heterostructures along the visible spectrum. These heterostructures exhibited remarkable visible light driven photocatalytic activity (99% efficiency) on par with pristine ZnO. The findings also attest this new class of composite structures to open up new openings in diversified solar energy conversion related functions.

Double transition metal MXene (TixTa4-xC3) 2D materials as anodes for Li-ion batteries.

A bi-metallic titanium-tantalum carbide MXene, TixTa(4-x)C3 is successfully prepared via etching of Al atoms from parent TixTa(4-x)AlC3 MAX phase for the first time. X-ray diffractometer and Raman spectroscopic analysis proved the crystalline phase evolution from the MAX phase to the lamellar MXene arrangements. Also, the X-ray photoelectron spectroscopy (XPS) study confirmed that the synthesized MXene is free from Al after hydro fluoric acid (HF) etching process as well as partial oxidation of Ti and Ta. Moreover, the FE-SEM and TEM characterizations demonstrate the exfoliation process tailored by the TixTa(4-x)C3 MXene after the Al atoms from its corresponding MAX TixTa(4-x)AlC3 phase, promoting its structural delamination with an expanded interlayer d-spacing, which can allow an effective reversible Li-ion storage. The lamellar TixTa(4-x)C3 MXene demonstrated a reversible specific discharge capacity of 459 mAhg-1 at an applied C-rate of 0.5 °C with a capacity retention of 97% over 200 cycles. An excellent electrochemical redox performance is attributed to the formation of a stable, promising bi-metallic MXene material, which stores Li-ions on the surface of its layers. Furthermore, the TixTa(4-x)C3 MXene anode demonstrate a high rate capability as a result of its good electron and Li-ion transport, suggesting that it is a promising candidate as Li-ion anode material.