In a high relative humidity (RH) environment, it is challenging for ethanol sensors to maintain a high response and excellent selectivity. Herein, tetragonal rutile SnO 2 nanosheets decorated with NiO nanoparticles were synthesized by a two-step hydrothermal process. The NiO-decorated SnO 2 nanosheet-based sensors displayed a significantly improved sensitivity and excellent selectivity to ethanol gas. For example, the 3 mol% NiO-decorated SnO 2 (SnO 2 -3Ni) sensor reached its highest response (153 at 100 ppm) at an operating temperature of 260 °C. Moreover, the SnO 2 -3Ni sensor had substantially improved moisture resistance. The excellent properties of the sensors can be attributed to the uniform dispersion of the NiO nanoparticles on the surface of the SnO 2 nanosheets and the formation of NiO-SnO 2 p–n heterojunctions. Considering the long-term stability and reproducibility of these sensors, our study suggests that the NiO nanoparticle-decorated SnO 2 nanosheets are a promising material for highly efficient detection of ethanol.

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Scanning Kelvin probe microscopy is widely used to measure surface work functions and electrostatic potentials. However, its measurement accuracy suffers from a cantilever effect. The authors introduce a surface potential shield with aperture structure to eliminate cantilever effect. By varying dc biases on the shield, the strength of cantilever effect is deliberately moderated and linear regression can be used to extract the true surface potential. Experimental results show that this approach yields accurate potential measurement, especially when there is only a single potential domain within aperture. A mobile potential shield structure mounted on a micromanipulator can make this approach more versatile.

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Halloysite nanotubes (HNTs) were used to prepare polypropylene (PP) nanocomposites through a novel vane mixer. The effects of melt blend time and halloysite content on properties of composites were investigated. SEM analysis was performed to show that HNTs were well dispersed in PP matrix with the increase of mixing time. DSC showed both the degree of crystallinity and crystallization temperature increased due to the introduction of HNTs into PP, which indicating a potential nucleation effect induced by the nanotubes. TGA illustrated that the presence of HNTs had two opposite effects on the thermal behavior. A surface catalytic action of the halloysite speeded up thermal degradation of PP. However, this effect was reduced with improved HNTs dispersion. Rheological investigations revealed that rheological properties were significantly increased by the addition of low fraction of halloysite to PP. The 2 wt% HNTs nanocomposites reached maximum tensile strength because HNTs dispersed evenly in PP.