MXene is a two-dimensional star material that is even more popular than graphene. As an advanced manufacturer of MXene, Beike Nano has launched special offer activities, where MXene and other materials are 10% off. At the same time, Beike Nano has launched new mesoporous material products with more preferential prices.

【 Research Background 】

Ammonia (NH3) has been widely used in the production of various materials in the chemical industry, and is often used as a refrigerant to replace the harmful hydrochlorofluorocarbons in daily life. In order to effectively reduce the potential harm to human health, this colorless gas should be monitored continuously. Therefore, gas sensors have been developed to detect toxic, harmful and volatile gases present in the surrounding atmosphere. In recent years, flexible miniature gas sensors have attracted much attention due to their low cost, good biocompatibility, and ability to be integrated into smart wearable and portable electronic devices. We note that gas sensors integrated with such devices need to operate at room temperature to achieve low energy consumption and good sensing stability. In order to expand the use of NH3 gas sensors, it is better for these sensors to operate at room temperature; Flexible, durable, fabric based; And can work under high strain or large deformation conditions. Recently, it has been reported that graphene fibers (GFs) are an emerging graphene structure that can be prepared by wet spinning and dispersing high concentration GO. In fact, GFs has great advantages in the field of wearable gas-sensitive applications due to its fiber structure, flexibility, and light weight. In addition, it is worth noting that the wet spinning process of GO colloids allows co-assembly with non-spinnable nanomaterials into a fibrous form, giving it the opportunity to be used as a material for wearable and flexible gas sensing devices.

【 Introduction to Achievements 】

Recently, Professor Hyoun Woo Kim and Professor Tae Hee Han of Hanyang University published a paper titled: Room-Temperature, Highly Durable Ti3C2Tx MXene/Graphene Hybrid Fibers for NH3 Gas Sensing A method for preparing mixed fibers composed of layered Ti3C2Tx MXene and GO sheets by a plastic one-step wet spinning process was proposed. Whereas traditional GFs wet-spinning methods use metal ions such as Ca2+ and Al3+ to hold individual GO sheets together as fibers, this paper proposes a metal-ion-free adhesive process that solidifies the gel fibers through organic solvent diffusion. Because the residual additives will deteriorate the fiber properties, we use organic solvent system to avoid the use of additives. Therefore, the proposed fiber extrusion method can continuously stretch MXene/GO fibers to several meters in length. In addition, a standard fiber optic gas sensor is fabricated using MXene/rGO hybrid fiber. Compared with other specific materials, MXene/rGO hybrid fibers showed significantly improved NH3 sensing response (ΔR/R0 = 6.77%). These self-supporting, flexible MXene/rGO fibers exhibit good elasticity and stability against mechanical deformation, making them essential materials for portable wearable sensing devices. The spinning process described in this paper is universal and can be extended to other types of MXenes or nanomaterials.

【 Text and Text Guide 】

Figure 1. Physical representation images of MXenes and graphene nanosheets.

Figure 2. Preparation flow chart and physical picture of MXene/GO mixed fiber.

Figure 3. Raman and XPS representation images of MXene, GO,MXene/GO, and MXene/rGO.

Figure 4. Characterization of gas sensitivity of MXene film,rGO fiber, and MXene/rGO hybrid fiber.

Figure 5. Performance of MXene/rGO hybrid fiber under different bending conditions.

【 Summary 】

In this paper, a reliable and effective binder free wet-spun fiber process has been developed for layer-by-layer assembly of GO and Ti3C2TxMXene sheets. Due to the different reduction potentials of the two materials during thermal reduction, the MXene/GO fibers transfer oxygen from GO to MXene through a simple current displacement reaction. MXene/rGO hybrid fibers have excellent mechanical durability, flexibility and chemical activity at room temperature, which can be used in flexible and wearable gas sensors. The optimized bandgap and synergistic effect of MXene/rGO hybrid fibers and the increase of atomic oxygen content at the MXene end significantly improve the NH3 sensing response performance and lower power consumption. The bending fatigue test of MXene/rGO hybrid fiber shows that the folded surface and small holes in the cross section are the main reasons for its flexible structure. The deformation noise at this time (δR/R0 =±0.2%) is much less than the gas reaction, making it suitable for wearable devices. In addition, highly flexible MXene/rGO hybrid fibers were woven into experimental coats by simple conventional weaving methods and demonstrated reliable sensing capabilities. The novel route presented here provides an effective strategy for simple and scalable wet spinning of MXene/ graphene hybrid fibers, whose applications are not limited to wearable gas sensing, but are also highly attractive for a variety of next-generation flexible, portable wearable energy devices.