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Composed of the heart, cardiac valves and blood vessels, the blood circulation system can manage the aggregation and the movement of the blood regularly and efficiently. Due to the analogical fluidity of the charge carrier and the blood, such system may act as the inspiration to design the advanced gas-sensing material. As a proof-of-concept, firstly, the porous WO 3 monomer was synthesized and recombined with the one-dimensional NiO monomer through the P-N junction to construct a similar structure. Subsequently, a series of gas-sensing tests towards the ethanol were measured. The obtained result indicates this nature-inspired nanocomposite indeed shows an enhanced gas-sensing property towards the ethanol, testifying the rationality of our design. [ABSTRACT FROM AUTHOR]

In this paper, WO 3 ·H 2 O with different nanostructures from 0D to 3D were successfully synthesized via a simple yet cost-effective hydrothermal method with the assistance of surfactants. The structures and morphologies of products were investigated by XRD and SEM. Besides, we systematically explained the evolution process and formation mechanisms of different WO 3 ·H 2 O morphologies. It is noted that both the kinds and amounts of surfactants strongly affect the formation of WO 3 ·H 2 O crystals, as reflected in the tailoring of WO 3 ·H 2 O morphologies. Furthermore, the gas sensing performance of the as-prepared samples towards methanol was also investigated. 3D flower-like hierarchical architecture displayed outstanding response to target gas among the four samples. We hoped our results could be of great benefit to further investigations of synthesizing different dimensional WO 3 ·H 2 O nanostructures and their gas sensing applications. [ABSTRACT FROM AUTHOR]

Hollow spheres are usually fabricated by hard template methods or soft template methods with soft surfactants, which is quiet tedious and time-consuming. In this paper, NiO hollow spheres with fluffy surface were successfully synthesized by a facile hydrothermal method and subsequent calcination, where bubbles acted as the template. NiO hollow spheres exhibited excellent gas sensing performances, which results from its hollow structure and high specific surface area. In addition, a possible evolution mechanism of NiO hollow spheres was proposed based on experimental results. [ABSTRACT FROM AUTHOR]

Abstract: WO3 H2O with different morphologies were synthesized through hydrothermal method by adding different surfactants. The effect of surfactants on tailing morphology was investigated through XRD and SEM analyses in detail and the possible formation mechanism was discussed. Furthermore, the gas-sensing performances of obtained samples to ethanol were investigated. The results revealed that the WO3 H2O with the hierarchical architectures assembled by nanosheets shows the highest response to ethanol among four kinds of the nanostructures WO3. These results on the preparation, mechanism and gas sensing properties of WO3 H2O nanostructures hold great potential for the syntheses of oxide materials with novel nanostructures and their applications. [Copyright &y& Elsevier]

Abstract: NiO nanowires with high aspect ratio and dispersive distribution have been synthesized by a hydrothermal reaction of NiCl2 with Na2C2O4 and H2O in the simultaneous presence of ethylene glycol (EG) and polyethylene glycol (PEG). Then the products were obtained by the subsequent annealing at 400°C in air. The effect of –OH from EG and –O– from PEG in the formation of nanowires was discussed. And the gas sensing properties of the as-prepared NiO nanowires toward ethanol were investigated. A novel formation mechanism of nanowires was presented and the NiO nanowires were proved to have an excellent gas sensing performance. [Copyright &y& Elsevier]

Abstract: The structural, adsorptive and electronic properties of H2 adsorption on SnO2–F (110) surface are investigated by first-principles calculation. The results show that the F-doped (110) surface is more reducible than that of undoped SnO2 surfaces, which is mainly attributed to formation of the surface states and larger charges transfer between H2 molecule and the F-doped (110) surface. This simulation mechanism may provide the instruction to further explore the SnO2-based sensing materials. [Copyright &y& Elsevier]

Abstract: New morphologies often play an important role in deciding the properties of nanomaterials. In current study, we synthesize various types of low dimensional SnO2 nanostructure materials using a simple hydrothermal process. We find that the SnO2 nanorods, nanowires and nanosheets show higher gas response as well as lower operating temperature as compared to that of nanospheres. In addition, the obtained nanosheets SnO2 are found to show best sensing performances owing to the largest surface area and porous structure providing many quick passages to absorb and desorb gas, suggesting that the gas sensing properties of nanocrystals can be significantly improved by tailoring the shape and morphology of nanocrystals. Such an unexpected morphology holds substantial promise for rendering low dimensional nano-SnO2 as a potential gas sensing material for future sensor application. [Copyright &y& Elsevier]

Abstract: In this work we report microstructure and gas sensing property of the pristine SnO2 and (Ti,Sn)O2 solid solutions prepared via the hydrothermal method. Of all the examined volatile organic compound gases, the (Ti,Sn)O2 solid solution exhibits somewhat lower gas response as compared to that of pristine SnO2. Further, we perform a first principles calculation to establish a surface model for solid solution and estimate its atomic configuration. The tightness of Ti6C(Sn6C)O2C bond and high oxygen vacancy formation energy for solid solution suggest that less amount of pre-adsorbed oxygen was formed on the surface, ultimately resulting in sensing performance weakening. [Copyright &y& Elsevier]

Abstract: We report the microstructure and gas-sensing properties of La–TiO2 nanobelts prepared by the hydrothermal method. In particular, we make a comparison of the volatile organic compounds (VOCs) sensing properties between La–TiO2 nanobelts and La–TiO2 nanospheres. The results show that La–TiO2 nanobelts exhibit higher gas response as well as lower working temperature as compared to that of La–TiO2 nanospheres, suggesting that the gas sensing properties of nanocrystals can be significantly improved by tailoring the shape and the surface structure of nanocrystals. [Copyright &y& Elsevier]

Abstract: Most of volatile organic compounds (VOCs) are often harmful or even toxic for environment, which require in situ detection. Here, we demonstrate that the TiO2 additive can enhance significantly gas-sensing properties of the SnO2-based sensor to VOCs, independent of its content and the concentration of tested gases. The improved gas-sensing quantities of matter, i.e., maximum sensitivity, minimum gas concentration, optimal operating temperature, and response and recovery times, are found to satisfy the basic needs for a practical application, which renders the TiO2–SnO2 composite material promising for the development of sensor devices to VOCs. [ABSTRACT FROM AUTHOR]

Abstract: Unique assembled sphere-like WO3 architectures were successfully synthesized through a facile hydrothermal method in the presence of malic acid followed by subsequent heat treatment. We found that malic acid played a significant role in governing morphologies of WO3·xH2O precursors during hydrothermal process. A possible formation mechanism was also proposed in detail. Experimental results showed that the optimized hydrothermal precursor could be dehydrated to mixed composition of hexagonal and monoclinic WO3 with the unique sphere-like porous architecture after being annealed at 400°C for 2.5h. Besides, gas-sensing measurement indicated that the well-defined 3D assembled sphere-like architectures exhibited the highest sensor response to ethanol at the optimal temperature of 250°C among the samples. [Copyright &y& Elsevier]

Abstract: ZnO nanocrystals with various morphologies are synthesized via a simple and facile HMT assisted hydrothermal process. Here, HMT is introduced as a structure directing and assembling agent to controllable synthesis of ZnO architectures and the concentration of HMT play a critical role in producing such different ZnO morphologies. We find that the sandglass-like ZnO exhibit excellent sensing performances to the target ethanol gas owing to its largest amount of Zn-terminated ZnO (0001) polar surfaces, which can easily adsorb more oxygen species on the surface and therefore improve the gas-sensing performances of ZnO. Such an unexpected morphology holds substantial promise for rendering ZnO as a potential gas-sensing material for future sensor applications. [Copyright &y& Elsevier]