NiWO₄ Microflowers on Multi-Walled Carbon Nanotubes for High-Performance NH₃ Detection

Abstract

NiWO4 microflowers with a large surface area up to 79.77 m2·g–1 are synthesized in situ via a facile coprecipitation method. The NiWO4 microflowers are further decorated with multi-walled carbon nanotubes (MWCNTs) and assembled to form composites for NH3 detection. The as-fabricated composite exhibits an excellent NH3 sensing response/recovery time (53 s/177 s) at a temperature of 460 °C, which is a 10-fold enhancement compared to that of pristine NiWO4. It also demonstrates a low detection limit of 50 ppm; the improved sensing performance is attributed to the porous structure of the material, the large specific surface area, and the p–n heterojunction formed between the MWNTs and NiWO4. The gas sensitivity of the sensor based on daisy-like NiWO4/MWCNTs shows that the sensor based on 10 mol % (MWN10) has the best gas sensitivity, with a sensitivity of 13.07 to 50 ppm NH3 at room temperature and a detection lower limit of 20 ppm. NH3, CO2, NO2, SO2, CO, and CH4 are used as typical target gases to construct the NiWO4/MWCNTs gas-sensitive material and study the research method combining density functional theory calculations and experiments. By calculating the morphology and structure of the gas-sensitive material NiWO4(110), the MWCNT load samples, the vacancy defects, and the influence law and internal mechanism of gas sensitivity were described.

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Ultrasensitive, Transparent, Flexible, and Ecofriendly NO2 Gas Sensors Enabled by Oxidized Single-Walled Carbon Nanotube Bundles on Cellulose with Engineered Surface Roughness

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Field Effect Transistor Sensors Based on In‐Plane 1T′/2H/1T′ MoTe2 Heterophases with Superior Sensitivity and Output Signals

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