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Sulfur dioxide (SO2) is highly toxic, harmful to human health, and seriously pollutes the environment. In the present report, different ratios of MXene (Ti3C2Tx) loaded LaFeO3 nanotubes were obtained through etching and electrospinning techniques. The MXene/LaFeO3 composites were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope, X-ray photoelectron spectroscopy. The characterization results show that there is a good connection between MXene and LaFeO3. The gas sensitivity test shows that the 4 wt%-MXene/LaFeO3 nanocomposite material shows higher sensitivity, rapid response and recovery rate, excellent selectivity to SO2. The MXene/LaFeO3 sensor demonstrates excellent linear response within the concentration range of 1–50 ppm, enabling precise detection of SO2. When the SO2 concentration is 20 ppm, the MXene/LaFeO3 sensor’s response/recovery time is 92 s and 54 s respectively. This work confirms the advantages of MXene-loaded catalyst in SO2 gas detection. MXene/LaFeO3 nanocomposite is a promising candidate material for rapid detection of SO2. This study provides insights into MXene-based gas sensing materials, laying the theoretical foundation for the development and application of high-performance SO2 sensors. [ABSTRACT FROM AUTHOR]

Fast and efficient detection of harmful gases is especially significant for living environments and public health. The combination of two kinds of two-dimensional materials with different properties and morphologies can improve the carrier transmission rate, and the synergistic effect between them can effectively improve the sensing performances. In this study, flower-like SnSe2 and WS2 nanosheets were prepared, and the sensing performance of WS2/SnSe2 nanostructures for NO2 was investigated. The WS2/SnSe2 (1:1 volume ratio) composite material was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD), and results are described in detail. The WS2/SnSe2 sensor has a shorter response/recovery time (15/14 s) and high response toward NO2. Besides, the sensor exhibits excellent linearity and great selectivity. In addition, we also carried out density functional theory simulations to theoretically analyze and prove the possible sensitivity mechanism of the sensor. It is revealed that the adsorption capacity of SnSe2 for NO2 is enhanced after WS2 doping. The sensing performance can be attributed to the microflower morphology of WS2/SnSe2 and the p–n heterojunction. The WS2/SnSe2 sensor has huge application prospects for NO2 detection. [ABSTRACT FROM AUTHOR]

The combination of two-dimensional material MXene and one-dimensional metal oxide semiconductor can improve the carrier transmission rate, which can effectively improve sensing performance. We prepared a trimethylamine gas sensor based on MoO3 nanofibers and layered Ti3C2Tx MXene. Using electrospinning and chemical etching methods, one-dimensional MoO3 nanofibers and two-dimensional Ti3C2Tx MXene nanosheets were prepared, respectively, and the composites were characterized via XPS, SEM, and TEM. The Ti3C2Tx MXene–MoO3 composite material exhibits excellent room-temperature response characteristics to trimethylamine gas, showing high response (up to four for 2 ppm trimethylamine gas) and rapid response–recovery time (10 s/7 s). Further, we have studied the possible sensitivity mechanism of the sensor. The Ti3C2Tx MXene–MoO3 composite material has a larger specific surface area and more abundant active sites, combined with p–n heterojunction, which effectively improves the sensitivity of the sensor. Because of its low detection limit and high stability, it has the potential to be applied in the detection system of trimethylamine as a biomarker in exhaled air. [ABSTRACT FROM AUTHOR]

Light‐driven semiconductor gas sensors are attracting considerable research attention in the recent past. Among them, silver phosphate (Ag3PO4) material has excellent photocatalytic activities due to its high separation efficiency of electron‐hole pairs under visible light. Inspired by the above point of view, in this study, Ag3PO4 nanoparticles were successfully synthesized via simple precipitation method. The microstructure of Ag3PO4 nanoparticles were characterized by scanning electron microscopy (SEM). The crystalline phase and the composition of the elements and the chemical bonding states of the material were characterized by X‐ray diffraction (XRD) and X‐ray photoelectron spectroscopy (XPS), respectively. Then the gas sensing performance of Ag3PO4 to ammonia (NH3) was systematically explored at room temperature under the illumination of LED lamp and the same was compared with the dark condition as well. Interestingly, the response value to NH3 under LED lamp was 30 % higher than that of dark condition and the detection limit was found to be as low as 10 ppm at room temperature. This can be ascribed to the generation of more oxygen species under visible light, which benefitted for enhancing the gas sensing performance of the sensor. Surprisingly, Ag3PO4 sensor exhibited superior selectivity to NH3 under mixed target gases, which can be attributed to the lone pair electrons of NH3 that tend to coordinate the empty orbitals of silver atom. [ABSTRACT FROM AUTHOR]