Trimodally porous SnO2 nanospheres with three-dimensional interconnectivity and size tunability: a one-pot synthetic route and potential application as an extremely sensitive ethanol detector

Abstract

The rapid and effective transfer of chemical reactants to solid surfaces through porous structures is essential for enhancing the performance of nanomaterials for various energy and environmental applications. In this paper, we report a facile one-pot spray pyrolysis method for preparing highly reactant-accessible and porous SnO 2 spheres, which have three-dimensionally interconnected and size-tunable trimodal (microscale, mesoscale and macroscale) pores. For this synthetic method, macroscale polystyrene spheres and mesoscale-diameter, long carbon nanotubes were used as sacrificial templates. The promising potential of the SnO 2 spheres with trimodal pores (sizes ≈3, 20 and 100 nm) was demonstrated by the unprecedentedly high response to several p.p.b. levels of ethanol. Such an ultrahigh response to ethanol is explained with respect to the hierarchical porosity and pore-size-dependent gas diffusion mechanism.

A New Strategy for Humidity Independent Oxide Chemiresistors: Dynamic Self‐Refreshing of In2O3 Sensing Surface Assisted by Layer‐by‐Layer Coated CeO2 Nanoclusters

“…The chemiresistive gas sensing property of metal oxide semiconductors arises from the change in the carrier density due to the interaction between the gas and negatively charged oxygen ions adsorbed on the oxide surfaces . Irreplaceable advantages of oxide chemiresistors, such as high sensitivity and a simple sensing mechanism, allow the detection of trace concentrations of analyte gases, the facile integration of gas sensors or sensor arrays into a small device, and the realization of cost‐effective artificial olfaction . However, atmospheric water vapor (H 2 O) reacts with oxygen ions on the surface and forms less reactive hydroxyl groups (OH) prior to the gas sensing reaction, which significantly changes the sensor resistance and deteriorates gas response.…”

Two-Dimensional Transition Metal Disulfides for Chemoresistive Gas Sensing: Perspective and Challenges

“…Among various types of gas sensors, chemoresistive gas sensors based on semiconductors have been considered as suitable candidates for the IoT due to low cost and small size [3]. Gas sensors based on nanostructured semiconducting metal oxides (typically spherical nanoparticles) lead to high responses to various gases [4][5][6][7]. They should operate at elevated temperatures with external heaters in order to keep the materials sensitive to the target analytes.…”

Synergetic p+n Field-Effect Transistor Circuits for ppb-Level Xylene Detection

“…Although precise and reliable xylene detection can be realized by gas chromatograph spectroscopy [11]- [13] and fluorescence spectroscopy [14] etc., there are some major hurdles for real-time monitoring in sampling, high cost, and prolonged analysis time. Therefore, more and more attention has been paid to the metal oxide semiconductor (MOX) gas sensors due to their advantages of low cost, facile method, easy fabrication and real time monitoring [15]- [21]. However, though MOX sensors are successful in ppm level gas detection such as ethanol [22], [23], acetone [24]- [26], CO [27], [28] etc., it is still challenging for MOX sensors to detect xylene at ppb level, due to the relatively low response at this trace concentration.…”