Yonsei University recently published a research article "Sensing with MXenes

Yonsei University recently published a research article "Sensing with MXenes:" in the internationally renowned journal Advanced Materials. Progress and Prospects ", MXene's two-dimensional structure facilitates functionalization with various end groups, providing a large number of surface active sites. These parts can serve as highly sensitive sensory platforms for various external stimuli. In addition, the high conductivity of the MXenes is ideal for achieving low noise sensory responses. Thus, these properties suggest that MXenes is a very promising alternative sensor material that enables high sensitivity, extremely low detection limits (LOD) and minimum detectable quantities in a variety of sensor applications. Finally, the water dispersion of MXenes is conducive to environmentally friendly preparation and modification treatment; Therefore, they are more advantageous in terms of processing. This paper is divided into three parts, the first part: MXene introduction and sensor development; The second part: synthesis and properties of MXene; Part III: MXene Sensing applications (3.1 Chemical sensors; 3.2 Biosensor; 3.3 Physical Sensors).

21 September-2023

Overview of MXene sensors

MXene is considered by many research fields to be a revolutionary 2D material. Especially in the field of sensors, the high electrical conductivity and large surface area of MXENes-like metals are ideal properties as an alternative sensor material that can transcend the boundaries of existing sensor technology. This objective review provides a comprehensive overview of the latest advances in MXene-based sensor technology, as well as a roadmap for the commercialization of MXene-based sensors. The existing sensors are systematically divided into chemical sensors, biological sensors and physical sensors. Each category is divided into different subcategories according to the four basic working mechanisms of the sensor, namely, electrical, electrochemical, structural or optical sensing mechanisms. Representative structural and electrical methods are presented to improve performance in each category. Finally, the factors that hinder the commercialization of MXene sensors are discussed, and several breakthroughs are proposed to realize the commercialization of MXene sensors. This review provides broad insights on previous and existing MXene-based sensor technologies, as well as a vision for the future generation of low-cost, high-performance, and multimodal sensors for software electronics applications.

21 September-2023

Breakthrough progress! Ti3C2Tx new application

Studies have shown that single-layer Ti3C2Tx nanosheets have a light transmittance of about 97% in the visible region, and have metal conductivity and hydrophilicity, and can be stably dispersed in the water medium. Therefore, researchers have used single-layer Ti3C2Tx nanosheets to prepare transparent conductive materials, and have made a breakthrough. On February 7, 2023, ACS Nano reported that researchers developed a MXene dispersion solution with a high monolayer ratio, large size and narrow particle size distribution through the three-step method of etching, stripping and gradient centrifugation. The average size of Ti3C2Tx nanosheets is 12.2μm, and the maximum size can reach 30μm. The dispersion liquid contains almost no Ti3C2Tx fragments with the transverse size of nanometer. The researchers then prepared a transparent conductive electrode (TCE) with a highly dense microstructure by inducing the orientation of the nanosheets by shear force, which has good mechanical bending properties. In addition, the number of grain boundaries between the nanosheets is significantly reduced in the film assembled from the large-size nanosheets compared to the small-size nanosheets. Therefore, at a given thickness, the former has a higher conductivity, and its maximum TCE conductivity can reach ~20000 S/cm, while there is no obvious seepage problem at high light transmittance. On the same day, Advanced Functional Materials reported that by continuously optimizing the particle size distribution of MXene and the adaptation parameters of the slit coating, the researchers developed a large area uniform highly conductive film at room temperature, with extremely low surface roughness, which showed a significant mirror effect from a macro perspective. By adjusting the processing conditions, ink concentration and substrate type of slit coating, various transparent conductive films with excellent photoelectric properties can be obtained. At T=93%, the nanosheets can still be closely connected with each other, and the compact stack is arranged on the substrate to form a continuous conductive path, avoiding the seepage phenomenon under high light transmittance, achieving an average conductivity of 13 000 S/cm, and having a strong adhesion on the PET and glass substrate. On March 6, 2023, Nano Energy reported that researchers have integrated the Ti3C2Tx/ZnO structure into a flexible photodetector with integrated properties, including transparency and energy efficiency, with a transparent photodetector (TPDs) on an ITO/PET substrate with a visible light transmittance of up to 68%. Density functional theory calculations suggest Ti3C2Tx function layer has better charge transport channel, so as to improve the Ti3C2Tx/Al2O3 / ZnO/Ti3C2Tx/ITO/PET thermal photoelectric current detector, makes the TPDs response rate is 0.34 W - 1 A, The detection rate is 1.4 × 10 13Jones. Based on the ultra-fast optical response characteristics of TPDs (8 μs), it can effectively convert the Moss code in the encrypted optical signal into text information. We are looking forward to whether the single-layer Ti3C2Tx dispersion will glow and heat up in the field of transparent conductive films like graphene, carbon nanotubes and metal nanowires in the future.

21 September-2023

How did the carbon nanotubes in the top issue of 2023 perform

Carbon nanotubes, as one of the most representative materials in carbon nanomaterials, have been intensively studied for more than 30 years, and countless results have been achieved, and a number of excellent works have emerged in the top journal of 2023. On January 26, 2023, Nature Energy reported the application of CNT yarns in mechanical energy collectors. The device uses stretching to make the capacitance of the capacitor change, causing a current in the circuit, which converts mechanical energy into electrical energy. The researchers prepared the twisted yarn of CNT by modifying the twisting mode of conical rotation to twisting mode. This mechanical energy collector based on CNT yarns has improved its energy conversion efficiency from 7.6% to 17.4% (stretching) and 22.4% (twisting). For mechanical energy harvesting between 2 and 120 Hz, this twisted pair wire has higher gravitational peak power and average power than non-twisted pair mechanical energy harvesters that have been reported. On February 9, 2023, Advanced Energy Materials reported that researchers have used a self-assembly strategy of covalent organic scaffold membranes to give the membranes (HB/CNT@COF) multiple functions (sodium ion transport, confinement, and polysulfide conversion) to maintain the stability of RT/Na-S battery systems. Due to the synergistic action of hydroxynaphthol blue (HB) and multi-walled carbon nanotubes (CNT), the HB/CNT@COF battery has a capacity of 733.4mAh g-1 with limited capacity attenuation after 400 cycles at 4 C, which is almost 4 times that of commercial glass fiber membranes. In addition to the above reports, Applied Catalysis B: Environmental reported the application of carbon nanotubes in oxygen catalysis, oxygen reduction catalysis in zinc-air batteries, and efficient electrochemical CO2 conversion in a number of consecutive articles in February, and carbon nanotubes have mushroomed in various top journals, which shows their position in the field of nanomaterials. How did the carbon nanotubes in the top issue of 2023 perform

21 September-2023

Transition metal catalysts include transition

Transition metal catalysts include transition metal hydroxides, oxides, sulfides, phosphates, and alloys. Molybdenum is a transition metal for NRR, and several molecular complexes based on molybdenum have been developed for electrocatalytic ammonia synthesis, such as molybdenum oxide, molybdenum nitride, molybdenum carbide and molybdenum sulfide, which can be used for NRR reactions, with MoS2 being the most widely studied. The edge of MoS2 is the active site of the electrocatalytic reaction and can be used to electrocatalyze NRR. In addition, MXenes materials have good mechanical properties and large specific surface area, and their electrical conductivity and abundant active sites on the base surface play an important role in the development of electrocatalysis. MXene materials have been shown to be useful for electrocatalysis of HER/OER/ORR reactions. Transition metal catalysts include transition metal hydroxides, oxides, sulfides, phosphates, and alloys. Molybdenum is a transition metal for NRR, and several molecular complexes based on molybdenum have been developed for electrocatalytic ammonia synthesis, such as molybdenum oxide, molybdenum nitride, molybdenum carbide and molybdenum sulfide, which can be used for NRR reactions, with MoS2 being the most widely studied. The edge of MoS2 is the active site of the electrocatalytic reaction and can be used to electrocatalyze NRR. In addition, MXenes materials have good mechanical properties and large specific surface area, and their electrical conductivity and abundant active sites on the base surface play an important role in the development of electrocatalysis. MXene materials have been shown to be useful for electrocatalysis of HER/OER/ORR reactions.

21 September-2023