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Three-dimensional (3D) tungsten oxide nanowire networks have been demonstrated as a high-surface area material for building ultrasensitive and highly selective gas sensors. Utilizing the 3D hierarchical structure of the networks, high sensitivity has been obtained towards N O 2⁠, revealing the capability of the material to detect concentration as low as 50 ppb (parts per billion). The distinctive selectivity at different working temperatures is observed for various gases. The results highlight that the nanobelts (nanowires) technology can be adopted for the development of gas sensors with performances suitable for practical applications.

The performance of a solid-state gas sensor is characterized by its sensitivity, stability, and selectivity. The working principle relies on modulation of electrical conductivity due to surface oxidation (reduction) caused by gas exposure. Because only the surface layer is affected by such …