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Nitrogen dioxide (NO2) is a major pollutant that poses significant risks to sustainable human life. As a result, a growing focus has been placed on the development of highly selective and sensitive gas sensors for NO2. Traditional cutting-edge non-organic NO2 gas detectors often necessitate stringent production conditions and potentially harmful materials, which are not environmentally friendly, and these shortcomings have limited their widespread practical use. To overcome these challenges, we synthesized self-assembled peptide nanotubes (SPNTs) through a molecular self-assembly process. The SPNTs were then combined with SnO2 in varying proportions to construct NO2 gas sensors. The design of this sensor ensured efficient electron transfer and leverage the extensive surface area of the SPNTs for enhanced gas adsorption and the effective dispersion of SnO2 nanoparticles. Notably, the performance of the sensor, including its sensitivity, response time, and recovery rate, along with a lower detection threshold, could be finely tuned by varying the SPNTs content. This approach illustrated the potential of bioinspired methodologies, using peptide self-assemblies, to develop integrated sensors for pollutant detection, providing a significant development in environmentally conscious sensor technology. [ABSTRACT FROM AUTHOR]

This present study reported a high-performance gas sensor, based on In2O3/ZnO composite material modified by polypeptides, with a high sensibility to NO2, where the In2O3/ZnO composite was prepared by a one-step hydrothermal method. A series of results through material characterization technologies showed the addition of polypeptides can effectively change the morphology and size of In2O3/ZnO crystals, and effectively improve the sensing performance of the gas sensors. Due to the single shape and small size, In2O3/ZnO composite modified by polypeptides increased the active sites on the surface. At the same time, the gas sensing properties of four different ratios of polypeptide-modified In2O3/ZnO gas sensors were tested. It was found that the In2O3/ZnO-10 material showed the highest response, excellent selectivity, and good stability at room temperature under UV light. In addition, the response of the In2O3/ZnO-10 gas sensor showed a strong linear relationship with the NO2 gas concentration. When the NO2 gas concentration was 20 ppm, the response time was as quick as 19 s, and the recovery time was 57 s. Finally, based on the obtained experimental characterization results and energy band structure analysis, a possible gas sensing mechanism is proposed. [ABSTRACT FROM AUTHOR]

In this work, a novel gas sensor based on ZnO/silk fibroin (ZnO/SF), which was synthesized by the hydrothermal method, was proposed for efficient and fast detection of NO 2 gas under the irradiation of 365 nm UV-light at room temperature. The prepared ZnO/SF sensor activated by UV showed a high sensing response of about 85 towards 20 ppm NO 2 gas at room temperature with an average response and recovery time of 26 s and 16 s, respectively. Test results of 1 ppm, 5 ppm, 10 ppm, 20 ppm NO 2 gas indicated that the ZnO/SF sensor had a very excellent response and linearity. Additionally, the sensing mechanism was analyzed as well. [ABSTRACT FROM AUTHOR]

[Display omitted] • At present, most CO sensors possess high operation temperature, high power consumption and low stability. We proposed a high-performance CO sensor at room temperature. • The SnO 2 /graphene nanocomposite exhibits unique morphology with SnO 2 nanoparticles dispersing in graphene nanosheets, which exerts a great effect on in improving sensing performance of CO. • The sensor shows improved CO gas response (R≈5.9 at 40 ppm CO) compared with pure SnO 2 (R≈3.27 at 40 ppm CO). Moreover, the sensor also exhibits fast response and recovery time (37 s/43 s). A low concentration CO gas sensor at 25 °C based on SnO 2 modified graphene nanocomposite was reported in this paper. The SnO 2 /graphene nanocomposite has higher CO gas sensing performance than pure SnO 2. The SnO 2 /graphene nanocomposite showed a high response to CO (R ≈ 5.9 at 40 ppm CO) at 25 °C and shorter response and recovery times (37 s/43 s), excellent repeatability and good stability. The excellent CO sensing performance of the composites is due to graphene's ability to provide a large surface area for adsorption sites and its capacity to prevent the disagglomeration of SnO 2 nanoparticles. [ABSTRACT FROM AUTHOR]

In consideration of the different electron structure-associated physical properties and internal sensing merits of MoS 2 and SnO 2 , this work reports a nanocomposite with unique structure of MoS 2 nanosheets dispersed SnO 2 nanoparticles. The sensing performance of MoS 2 /SnO 2 sensor toward low concentration CO was investigated at room temperature under the UV light illumination. It was found that MoS 2 /SnO 2 sensor shows improved CO gas response (R ~ 4.97 at 40 ppm CO) compared with pure SnO 2 (R ~ 3.27 at 40 ppm CO), which is due to the unique structure and the formation of heterostructure between MoS 2 and SnO 2. Moreover, the fabricated sensor also exhibits fast response and recovery time (43 s/36 s). The sensor provides a potential platform for monitoring CO gas at room temperature. [ABSTRACT FROM AUTHOR]

• The morphology of ZnO materials were regulated with polypeptides assisted. • The ZnO/polypeptides materials have good NO 2 gas-sensing performances at room temperature under UV activated. • The ZnO/polypeptides-based sensor also has short response time and good linearity towards NO 2. In this work, nanoflowers-like, nanoneedles-like ZnO and ZnO nanorods have been successfully synthesized by polypeptide-assisted hydrothermal routes. The nanostructures and morphologies of the ZnO crystals were studied through X-ray diffraction (XRD), scanning electron microscopy (SEM), and it was shown that the additive of polypeptides could control the morphologies. The gas sensing properties of NO 2 have been investigated with the three ZnO materials, which showed that the ZnO nanorods-based sensor exhibits the highest response under 365 nm UV illumination at room temperature. Gas sensing results, towards NO 2 at a range of gas concentrations (10–25 ppm), also indicated it had good linearity and repeatability. [ABSTRACT FROM AUTHOR]