ChemNanoMat最新文献

Tantalum carbide MXene (Ta₄C₃T_x) were synthesized via HF etching of the Al intermediate layer from the parental tantalum aluminium carbide MAX phase (Ta₄AlC₃). The structural and vibrational studies confirm the formation of MXene from the MAX phase without disturbing the hexagonal crystal structure. The synthesized samples were analysed using XRD to understand the phase structure. In and out of plane vibrational properties were examined by Raman spectrometer. XPS confirms the successful HF etching of Al in MXene phase and all other elemental configurations. HR-SEM and HR-TEM revile the exfoliated layered structure of the MXene and hexagon diffraction pattern of the tantalum carbide MXene sample with increased d-spacing. The TGA analysis demonstrated the thermal stability of the as-synthesized post measured compounds. The synthesized tantalum carbide MXene shows stable thermoelectric properties over six thermal cycles. The temperature dependent transport properties were measured from 303 K to 803 K. Ta₄C₃T_x MXene shows a maximum Seebeck coefficient of 13.8 μV/K and a power factor of 1.88 μW/mK² with the low lattice thermal conductivity of 5.42 W/mK at 803 K. In this present investigation, Tantalum carbide MXene demonstrated a decent thermoelectric property with high thermal cycling stability.

Recently, the electronic skin (E-skin) based on triboelectric nanogenerators (TENGs) has exhibited enormous potential in smart sports. However, TENGs device installed on human body usually faces challenges in complex mechanical environments. Here, we proposed a flexible TPU/MXene/carbon conductive electrode and combined with PDMS to prepare triboelectric nanogenerator (PT-TENG) to harvest mechanical energy. Moreover, to demonstrate the application of PT-TENG in smart sports, we can use it to monitor the posture changes of human joints during Tai Chi exercise and heart rate. The transfer charge (Q_sc) of PT-TENG can arrive at 104.65 nC, which is superior to the output performance produced by using traditional metal aluminum foil to prepare TENG device. The PT-TENG can obtain the maximum output power of 132.34 μW under the working frequency 2 Hz. The experimental results show that PT-TENG installed on the fingers, wrists, and knees of the human body can effectively perceive the bending angle of joints, which is very meaningful for evaluating the posture of movements in Tai Chi training. This research provide an effective path to promote the application of the self-powered E-skin based on TENG device on the smart sport field.

The quest for novel chromophoric materials with tunable properties to match the natural spectrum of skin tones lacks comprehensive solutions, particularly in harnessing natural proteins for pigment synthesis. This research delved into the synthesis of sub-micron Keratin-Cysteine particles inspired by natural pigment production pathways. Adjustment of the initial conditions of the water-based reaction between keratin, tyrosinase and cysteine, yielded Keratin-Cysteine particles with colors tunable within the light to intermediate skin tone range. A systematic investigation of the reaction conditions through factorial design of experiment (DOE) identified the sequence of addition of tyrosinase and cysteine as the key determinant of color tone. Ultraviolet-visible (UV-Vis) spectroscopy, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and color analysis were performed to elucidate the reaction mechanism. This research presents a promising approach to chromophore synthesis for cosmetic and biomedical applications.

The exploration of semiconductor nanostructures utilizing mixed metal materials is an emerging area of study across fields including field-effect transistors, chemical sensors, photodetectors, photocatalysts, and many more. In this study, Schottky diodes based on ZnFe₂O₄ (ZFO) were constructed with an aim to tune their electronic and optoelectronic characteristics. Here, Ni doping facilitated the tuning of electronic properties, leading to a significant increase in the rectification ratio from 238 to 1172, along with a reduction in the potential barrier height from 0.67 V to 0.65 V. This is attributed to Ni's role as a charge carrier in ZFO, enhancing carrier concentration, confirmed by Mott-Schottky analysis. The 5 mol % Ni-doped ZFO also exhibited remarkable light sensitivity, with its rectification ratio surging to 1795 under illumination, four times that of the undoped version. Additionally, its photo-sensitivity soared to 42.46 %, nearly quadrupling the undoped device's performance, and its power gain impressively climbed to 38.4 %, which is over twelvefold the undoped sample's output. Furthermore, the diode responds strongly to optical illumination, making this structure suitable for use as a photodiode or photosensor. Apart from that by employing a doping strategy, we achieved 64.61 % degradation of methylene blue dye under visible light in 120 minutes, compared to 36.85 % for the undoped sample. These indicate that hydrothermally synthesized Ni-doped ZFO is promising for visible light-driven multifunctional applications.

In recent years, the research and development of various flexible wearable devices have rapidly advanced due to the continuous introduction of flexible electronic product. These devices have found applications in health monitoring, cardiovascularcare, internal and external workload, and more.Flexible sensors, being a vital component of flexible devices, determine the functionalities and performance capabilities of the devices. Metal nanomaterials, especially silver nanowires, are widely used in flexible sensors in past research due to their great advantages in flexibility and sensitivity. In this work, Silver nanowires with aspect ratios of 600, 1000, and 1400 were synthesized by adjusting the synergy of Br- and Cl-, along with other process parameters, leading to an improved production efficiency of silver nanowires.The stability of the conductive network is enhanced when the aspect ratio of silver nanowires is 1000 and 1400.The sensor demonstrated high sensitivity at high strain, along with an extended strain range.Moreover, it was observed that increasing the aspect ratio of silver nanowires led to a more stable conductive network, thus enhancing the sensor's stability with over 10000 stretching cycles. under the appropriate deposition density, silver nanowires with aspect ratio of 600 have high sensitivity to low strain, and silver nanowires with aspect ratio of 1400 have high sensitivity to high strain, up to 247.3. Introducing microstructures on the surface of PDMS resulted in an increased maximum sensitivity of the sensor with decreasing microstructure size, reaching a maximum sensitivity of 322.2.

The global issue of plastic waste accumulation is now widely acknowledged as a significant environmental challenge that affects all aspects of life, economies, and natural ecosystems worldwide. Hence, it is crucial to develop sustainable solutions to traditional disposal methods. One promising solution involves upcycling plastic waste into valuable carbon nanomaterials such as carbon nanotubes, graphene, and carbon nanofibers, among others. This critical review provides an overview of the problems associated with plastics, including their various types and properties, as well as their significant impact on the environment and the methods currently employed for waste management. Furthermore, it delves into recent advancements in upcycling plastic waste into carbon nanomaterials through four state-of-the-art methods with the potential for scaling up and enabling industrial applications: thermal decomposition, flash joule heating (FJH), chemical vapor decomposition (CVD), and stepwise conversion. For each method, highly influential and seminal papers were selected, and their research approaches and observed results were thoroughly analysed. This upcycling approach transforms plastic waste into valuable resources, promoting a waste-to-value concept that reduces environmental impact and supports the circular economy. By creating new materials from discarded plastics, it addresses waste management challenges while generating economic value.

Environmental hazards, especially particulates, and microbiological pollutants, have resulted in significant negative impacts on human health. In this study, 3D biodegradable cellulose filters were made from nanocellulose and tested for the removal efficiency of airborne particulates. Cellulose was first extracted from palm empty fruit bunches (EFBs) using green Deep Eutectic Solvents (DESs) under moderate temperature and then homogenized at high pressure to produce cellulose at the nanoscale size. Three types of renewable choline chloride (ChCl)-based DESs were used: lactic acid, 1,3-butanediol, and oxalic acid. The maximum cellulose yield from DES pretreatment was 38.78 % based on raw EFB (100 % cellulose yield based on cellulose in EFB) with ChBu60 C and the maximum nanocellulose yield was 68.49 % based on cellulose in EFB with ChLa80 C after 12-pass high pressure homogenization. The cellulose air filter was fabricated using tert-butyl alcohol (tBuOH) solvent exchanged under freeze-drying conditions and characterized by different state-of-the-art techniques. It was shown that the ChBu80 C filter had the lowest pressure drop (10.16 mmH₂O or 2.07 mmH₂O cm⁻²) and the maximum particle filtration efficiency (32.51 % for 0.1 μm and 93.63 % for 1.0 μm particles). The process simulation and techno-economic analysis were performed for nanocellulose production and air filter fabrication to select the most feasible technology.

Green hydrogen production by water splitting holds great potential as a clean and renewable source of energy for sustainable energy solutions. However, the efficiency of this process is hampered by the sluggish oxygen evolution reaction (OER). Overcoming these kinetic hurdles requires the development of highly efficient electrocatalysts. This study explores the effect of transition metal doping on the electrocatalytic properties of Ni(OH)₂ microflowers towards alkaline OER. Transition metal-doped Ni(OH)₂ microflowers, with highly porous structures due to interconnected nanosheets, are synthesized by a facile, cheap, and scalable chemical bath deposition (CBD), and combined with graphene paper (GP) substrates to fabricate electrodes. Through a systematic exploration of the relationship between the transition metal dopant element type (Mn, Fe, Co, Zn) or concentration and the consequent electrochemical properties, Co-doping demonstrates improvement in the overpotential at a current density of 10 mA cm⁻² (329 mV), Tafel slope (45 mV dec⁻¹), and other key performance indicators of Ni(OH)₂ microflowers for OER. These results are attributed to the high number of active sites and their enhanced electrocatalytic activity benefiting from the presence of the transition metal dopant. The proposed strategy paves the way for the development of cost-effective and highly efficient electrocatalysts for water splitting technologies.

In recent years, Ag−In−Ga−S (AIGS) quaternary quantum dots (QDs) have garnered significant attention as a novel class of environmentally friendly and non-toxic QDs. However, the hydrothermal synthesis method for aqueous QDs has been plagued by issues such as inconsistent size, subpar crystallinity, and low photoluminescence quantum yield (PLQY). Herein, we developed a dual ligand strategy based on the hard and soft acids and bases (HSAB) theory to synthesize aqueous AIGS QDs with an impressive PLQY of up to 64.3 %, currently the highest value among hydrothermal-synthesized uncoated I–III–VI QDs. The QDs exhibit better crystallinity, narrow size distribution (3.07±0.31 nm), and remarkable stability. The mechanism underlying this dual ligand strategy was further elucidated, shedding light on the distinct influences of different ligands on the growth of QDs. The high PLQY contributes to the further application of aqueous AIGS QDs in luminescent displays and the field of biology. Meanwhile, this ligand strategy has broad reference significance for efficient preparation of other water-soluble QDs.