Search

• SnS 2 /ZnS heterojunction was successfully obtained via transforming ZnSn(OH) 6 precursor. • The synthesized SnS 2 /ZnS microspheres were composed of ultrathin nanoflakes. • The sensor of SnS 2 /ZnS exhibited ultrafast respose/recovery time (2/8 s) to 50 ppm TEA. • The SnS 2 /ZnS sensor showed excellent selectivity and antihumidity ability. • The sensing mechanism and humidity effects were discussed in detail. At present, gas sensors have promising prospects in terms of gas monitoring. Heterostructure with high carrier transport property is an alternative strategy to enhance the gas sensitivity. Herein, we directly transformed ZnSn(OH) 6 microspheres to obtain SnS 2 /ZnS heterostructures through a low-cost hydrothermal treatment. Hierarchical SnS 2 /ZnS flowerlike microspheres consisting of ultrathin nanoflakes subunits were successfully synthesized without any impurities. The more attractive finding is the great improvement of triethylamine gas-sensing properties of the SnS 2 /ZnS composite compared to the pure SnS 2 at 180 °C. Especially, the proposed SnS 2 /ZnS sensor demonstrates ultrafast responding and recovering time (2/8 s) to 50 ppm TEA. Such significantly enhanced sensing properties can be ascribed to the merit of heterojunction and high specific surface area provided by flakes-assembled flowerlike structure. Moreover, the convenient synthetic route paves the way to the future design of various heterojunctions for diverse gas detection. [ABSTRACT FROM AUTHOR]

• The degree of lattice distortion of perovskite can be tuned by the B-site element. • The perovskite with Fe at B site has better sensing performance to ethylene glycol. • The good performance relies on pore size, oxygen vacancy, lattice distortion and conductivity. [Display omitted] The target of this work is to survey the consequences of various B (B Fe, Co) sites of SmBO 3 perovskite on crystal structure and ethylene glycol gas-sensitive properties. To this end, two samples based on SmFeO 3 and SmCoO 3 nanofibers with orthorhombic phase were prepared by a straightforward and efficient electrospinning technique and calcined at 700 °C. The XRD Rietveld refinements and tolerance factor (t) were implemented to research the crystal structure by the lattice parameters, size of B O B angles and t value, BET test shows that as-prepared two samples own different pore sizes, and XPS analyzes the composition and chemical state toward two samples, which indicates that more oxygen vacancies exist in SmFeO 3 surface. Then, the gas-sensing performance of SmFeO 3 and SmCoO 3 nanofibers were compared at their optimal working temperature of 200 °C. The gas-sensing inquiries exhibit that the response of sensor based on SmFeO 3 nanofiber (14.3) is almost 6.5 times higher than that of SmCoO 3 (2.2) toward 100 ppm ethylene glycol. Finally, the sensing mechanisms of SmFeO 3 and SmCoO 3 nanofibers were also explained based on pore size, oxygen vacancy, lattice distortion and electrical conductance. [ABSTRACT FROM AUTHOR]

• Different morphology BiVO 4 samples were fabricated via a facile hydrothermal method. • The coral-like BiVO 4 -6 has an excellent gas-sensing response and selectivity to ethylene glycol. • This modulated method is simple and easy to come true. Different morphologies of BiVO 4 samples have been successfully fabricated via a facile hydrothermal method. Their morphologies were modulated via altering the pH of solvent. The characterization results reveal that the typical BiVO 4 -1 is decagonal and BiVO 4 -6 is coral-like. The gas sensing test results illustrate that the coral-like BiVO 4 -6 has an excellent gas-sensing response. (The response value reaches 86.49–100 ppm EG at 340 °C) and the sensor still gives an obvious response value (10.21) even upon exposure to 5 ppm EG. The good selectivity toward EG might be due to that EG owns the lowest bond dissociation energy, and the reason for enhancing responses can be the reduction of grain size and the increase of surface area. Thus, all test results illustrate that the coral-like BiVO 4 -6 is a promising candidate to detect EG. [ABSTRACT FROM AUTHOR]

The coral-like pure and Sm doped PrFeO 3 (Sm-PrFeO 3) nanocrystallites were fabricated through a facile and cost-efficient hydrothermal method by employing a mixture of ethylene glycol and deionized water, and their various properties including structure, phase composition, morphology and gas sensing properties were systematically studied. The XRD and XPS test and preparation process showed that Sm3+ has been successfully embedded into the PrFeO 3 lattice. The response value reaches 44.94–50 ppm acetone at 270 °C, which decreases by 10 °C than that of the pristine PrFeO 3 sensor, even to 5 ppm acetone with a high response value of 3.70. What's more, the recovery time is vastly shorted. The improvement of gas sensing performance may be ascribed that the Sm-PrFeO 3 owns cage morphology, which modifies the diffusion paths of the gas molecules, in addition, the doping Sm3+ makes the bandgap energy get narrower and increases conductivity of materials. Besides, the Sm-PrFeO 3 owns stronger moisture resistance and well recovery speed to acetone below 71% RH. ga1 • The coral-like Sm doped PrFeO 3 were successfully fabricated for the first time via a one-step hydrothermal method. • The Sm doped PrFeO 3 gas sensor has a good sensing response to acetone at 270 °C. • The Sm doped PrFeO 3 gas sensor owns larger pore which shorted recovery time. • The Sm-PrFeO 3 owns stronger moisture resistance and well recovery speed to acetone below 71% RH. [ABSTRACT FROM AUTHOR]