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(Na 0.5 Bi 0.5 ) 0.94 TiO 3 –Ba 0.06 TiO 3 (NBT–BT6) nanofibers were synthesized by electrospinning and characterized by X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy. The humidity sensor was fabricated by coating NBT–BT6 nanofiber on a ceramic substrate with Ag–Pd interdigitated electrodes. At 100 Hz, the impedance of the humidity sensor changed by more than five orders of magnitude with the relative humidity (RH) changing from 11% to 95%. The response time and recovery time were about 2 s and 50 s, respectively, and the maximum hysteresis was around 5% RH. The results indicate that NBT–BT6 nanofibers are of great potential for high-performance humidity sensor applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • DFT calculations are performed to study the properties of S-doped MnOOH. • MnOOH nanofibers are prepared through a one-step hydrothermal method. • S doping improves the electronic/ionic transport and structural stability of MnOOH. • Ex situ XRD, Raman, XPS, and SEM tests reveal Zn2+/H+ insertion-type mechanism. • Low and high mass loading electrodes show impressive electrochemical performances. MnOOH is regarded as a product of manganese-based materials after H+ insertion. There is rare study on the Zn2+/H+ storage capability of MnOOH. Herein, MnOOH nanofibers are prepared through a one-step hydrothermal method and developed as a promising cathode. The introduction of S doping changes the crystal structure of MnOOH and is conducive to its electronic/ionic transport and structural stability, proven by density functional theory calculations and various characterizations. The reduced Zn2+ diffusion barrier of S-doped MnOOH leads to its increased Zn2+ storage capability in the test of rate capability, especially at large current density. The Zn2+/H+ insertion-type mechanism of MnOOH is revealed by ex situ XRD, Raman, XPS, and SEM tests. Therefore, this optimized material delivers a high reversible capacity of 178 mAh g−1 at 0.1 A g−1, a good rate capability of 50 mAh g−1 at 3.0 A g−1, and a long cyclic life with 108 mAh g−1 at 0.5 A g−1 over 500 cycles. Moreover, the electrode still shows satisfactory rate capability and cyclic life even at the high mass loadings of 10 and 15 mg cm−2. This work proves the Zn2+/H+ storage capability of MnOOH and its potential as a high-performance cathode in aqueous zinc ion battery. [ABSTRACT FROM AUTHOR]

(GaN) 1-x (ZnO) x composite nanofibers with hollow structure were prepared by initial electrospinning, and the subsequent calcination and nitridation. The structure and morphology characteristics of samples were investigated by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM). The characterization results showed the phase transition from ZnGa 2 O 4 to (GaN) 1-x (ZnO) x solid-solution under ammonia atmosphere. The preparation conditions were explored and the optimum nitridation temperature and holding time are 750 °C and 2 h, respectively. The photocatalytic properties of (GaN) 1-x (ZnO) x with different Ga:Zn atomic ratios were investigated by degrading Rhodamine B under the visible light irradiation. The photocatalytic activity sequence is (GaN) 1−x (ZnO) x (Ga:Zn = 1:2) > (GaN) 1−x (ZnO) x (Ga:Zn = 1:3) > ZnO nanofibers > (GaN) 1−x (ZnO) x (Ga:Zn = 1:4) > (GaN) 1−x (ZnO) x (Ga:Zn = 1:1). The photocatalytic mechanism of the (GaN) 1−x (ZnO) x hollow nanofibers was further studied by UV–vis diffuse reflectance spectra. The excellent photocatalytic performance of (GaN) 1−x (ZnO) x hollow nanofibers was attributed to the narrow band gap and high surface area of porous nanofibers with hollow structure. [ABSTRACT FROM AUTHOR]

Abstract: SnO2 nanofibers with and without block copolymer P123 (EO20PO70EO20) in the precursor are synthesized via a simple electrospinning method. The Brunauer–Emmett–Teller surface areas of the nanofibers with and without P123 are 113.261 and 18.025m2 g−1, respectively. Gas sensing properties of these two samples are investigated by exposing the corresponding sensors to NH3, C2H5OH, and CH3COCH3 at 280, 300, and 340°C, respectively. Comparing with nanofibers without P123, the SnO2 nanofibers with P123 hold enhanced response value, higher saturated-detection-concentration, and lower minimum-detection-limit. The response is 59, 75, and 65 for nanofibers with P123 to 500ppm NH3, C2H5OH, and CH3COCH3, respectively, and is 28, 50, and 43 for nanofibers without P123. The minimum-detection-limit is 5, 1, and 1ppm for nanofibers with P123 to detect NH3, C2H5OH, and CH3COCH3, respectively, and is 50, 20, and 10ppm for nanofibers without P123. The improved gas sensing properties are based on their coarse and loose morphology and higher Brunauer–Emmett–Teller surface area brought by adding P123. [Copyright &y& Elsevier]

Abstract: Pure and KCl-doped TiO2 nanofibers with different crystallographic structures are synthesized by electrospinning and calcination techniques, and their humidity sensing properties are investigated. KCl-doped TiO2 nanofibers with mixed anatase and rutile structures show the highest sensing performance. The impedance of this sample linearly decreases by more than four orders of magnitude with increasing relative humidity from 11% to 95% on a semilogarithmic scale. Both the response time and recovery time are about 3s. Excellent selectivity, prominent stability, and good reproducibility are also observed based on this sample. The high humidity sensing performance is explained in terms of the ionic contribution of KCl doping and dissociating promotion of mixed crystallographic structure. [Copyright &y& Elsevier]

Abstract: KCl-doped ZnO nanofibers are synthesized via an electrospinning method and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The humidity sensing properties of these nanofibers are investigated by screen-printing them on a ceramic substrate with a pair of Ag–Pd interdigitated electrodes. The experimental results show that the 5.7wt% KCl-doped ZnO nanofibers hold super-rapid response and recovery, high response value, good reproducibility, linearity, selectivity, and stability at 100Hz. Especially, the response time and recovery time is only about 2 and 1s, respectively. These results demonstrate the potential application of KCl-doped ZnO nanofibers for fabricating high performance humidity sensors. [Copyright &y& Elsevier]

Abstract: A simple method for the large-scale synthesis of SnO2 nanofibers has been demonstrated through an electrospinning method. The as-synthesized fibers are characterized by scanning electron microscopy, transmission electron microscopy, selected area electron diffraction, X-ray diffraction, and energy dispersive X-ray analysis. The sensor fabricated from these fibers exhibits high response to toluene at 350°C with good selectivity. The response time and recovery time are about 1 and 5s, respectively. The linear dependence of the response value on the toluene concentration is observed in the range of 10–300ppm. The potential application of SnO2 nanofibers for fabricating high performance toluene sensors at industry level has been demonstrated. [Copyright &y& Elsevier]