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• Synthesis of heterostructure NiO-ZnO nanodisks. • Utilization of NiO-ZnO nanodisks as gas sensor. • Fabrication of high sensitive and low-concentration sulfur dioxide gas sensor based on NiO-ZnO nanodisks. This paper reports the synthesis and characterization of NiO-ZnO nanodisks synthesized through a facile hydrothermal method. The morphological characterizations confirmed the formation of well-defined nanodisks in high density with an average thickness of 60 ± 5 nm. The x-ray diffraction analysis confirmed the well incorporation of the NiO into the matrix of ZnO crystal and the average crystallite size for the NiO-ZnO nanodisks was found to be 39.71 nm. The compositional analysis revealed the formation of pure NiO-ZnO nanostructures. The synthesized NiO-ZnO nanodisks were used as electrode materials to fabricate Sulfur dioxide (SO 2) gas sensors and the gas sensor response and recovery times were systematically analyzed with respect to the operating temperatures and the SO 2 gas concentration. The observed sensor gas response, response time and recovery time of the fabricated NiO-ZnO nanodisks based gas sensor were 16.25, 52 s and 41 s, respectively, towards 20 ppm SO 2 gas at an optimized temperature of 240 °C. Thus, it is believed that the NiO-ZnO nanodisks could be a promising candidate for the fabrication of efficient gas sensors towards toxic and hazardous gases. [ABSTRACT FROM AUTHOR]

Here, we reported the synthesis of pure CoSn(OH) 6 and Fe-doped CoSn(OH) 6 nanocubes for gas sensing application by hydrothermal method. The extensive characterizations determined the crystal structure, morphology and chemical composition of the samples, such as, XRD, SEM, XPS, etc. Compared with the pure CoSn(OH) 6 , the gas sensing performance of 5Fe-CoSn(OH) 6 to N-butyl alcohol is improved significantly. The 5Fe-CoSn(OH) 6 based sensor presented high gas response of 60.309 toward 30 ppm N-butyl alcohol at relatively low operating temperature of 200 °C. Moreover, the 5Fe-CoSn(OH) 6 based sensor also exhibited excellent stability, selectivity and humidity resistance to N-butyl alcohol. The gas sensing properties of 5Fe-CoSn(OH) 6 is greatly improved due to the large specific surface area, narrow band gap, sufficient oxygen vacancies and quickly separation efficiency of electrons-hole pairs. The results demonstrate that the doping of Fe3+ is an effective way to improve the gas sensing properties of CoSn(OH) 6 sensors to detect N-butyl alcohol. [Display omitted] • The pure CoSn(OH)6 and Fe-doped CoSn(OH)6 were successfully synthesized by a hydrothermal method. • The sensing properties of the pure CoSn(OH)6 and Fe-doped CoSn(OH)6 to N-butyl alcohol were investigated for the first time. • 5Fe-CoSn(OH)6 exhibits the most remarkable gas sensing performance to N-butyl alcohol at 200 ℃. • The doping of Fe3 + is a promising approach for achieving an excellent gas sensing performance for the development of CoSn(OH)6 gas sensors to detect N-butyl alcohol. [ABSTRACT FROM AUTHOR]

In this work, we designed and prepared CuO-loaded In 2 O 3 /CeO 2 nanofiber heterojunctions, which are promising for trace CO gas detection. We characterized the materials, confirmed the morphology of the nanofibers and structure of the p-n heterojunctions, and analyzed the effect of morphology and structure on the gas sensing performance. In gas sensing tests, the sensor is found to show a low optimum operating temperature of 70 °C, with a limit of detection that reaches as low as 50 ppb. At concentrations ranging from 50 ppb to 10 ppm, the sensor shows a sensitive and linear response for CO gas. In particular, the sensor shows a response (R a /R g) of 11.7–10 ppm CO gas, and a response/recovery time of 125 s/12 s for 2 ppm CO gas. In addition, we tested the selectivity, humidity response and long-term stability of the gas sensors. Finally, based on the structure of the materials, we propose a mechanism for the enhanced CO gas sensing performance. • CuO-loaded In 2 O 3 /CeO 2 nanofibers were synthesized for fabricating superior CO gas sensors. • CuO was loaded onto the surface of nanofibers to form p-n junctions, leading to enhanced sensing properties. • The CO gas sensor shows a low optimum operating temperature of 70 °C, with a limit of detection as low as 50 ppb. • Combined with the experimental results, the mechanism for the enhanced performance of the gas sensor is discussed. [ABSTRACT FROM AUTHOR]

In this work, we designed and prepared CuO-loaded In 2 O 3 /CeO 2 nanofiber heterojunctions, which are promising for trace CO gas detection. We characterized the materials, confirmed the morphology of the nanofibers and structure of the p-n heterojunctions, and analyzed the effect of morphology and structure on the gas sensing performance. In gas sensing tests, the sensor is found to show a low optimum operating temperature of 70 °C, with a limit of detection that reaches as low as 50 ppb. At concentrations ranging from 50 ppb to 10 ppm, the sensor shows a sensitive and linear response for CO gas. In particular, the sensor shows a response (R a /R g) of 11.7–10 ppm CO gas, and a response/recovery time of 125 s/12 s for 2 ppm CO gas. In addition, we tested the selectivity, humidity response and long-term stability of the gas sensors. Finally, based on the structure of the materials, we propose a mechanism for the enhanced CO gas sensing performance. • CuO-loaded In 2 O 3 /CeO 2 nanofibers were synthesized for fabricating superior CO gas sensors. • CuO was loaded onto the surface of nanofibers to form p-n junctions, leading to enhanced sensing properties. • The CO gas sensor shows a low optimum operating temperature of 70 °C, with a limit of detection as low as 50 ppb. • Combined with the experimental results, the mechanism for the enhanced performance of the gas sensor is discussed. [ABSTRACT FROM AUTHOR]