Titanium nitride sensor for selective NO<sub>2</sub> detection.

Zhao, Xuefei; Xu, Zhihang; Zhang, Zhaorui; Liu, Jiahao; Yan, Xiaohui; Zhu, Ye; Attfield, J Paul; Yang, Minghui · Nat Commun · 2025

basic_science · Level V

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Abstract

Efficient detection methods are needed to monitor nitrogen dioxide (NO<sub>2</sub>), a major NO<sub>x</sub> pollutant from fossil fuel combustion that poses significant threats to both ecology and human health. Current NO<sub>2</sub> detection technologies face limitations in stability and selectivity. Here, we present a transition metal nitride sensor that exhibits exceptional selectivity for NO<sub>2</sub>, demonstrating a sensitivity 30 times greater than that of the strongest interfering gas, NO. The sensor maintains stability over 6 months and does not utilize platinum or other precious metals. This notable performance has been achieved through preparation of highly active titanium nitride (TiN<sub>x</sub>) nanoparticles with exceptionally large surface area and a high concentration of nitrogen vacancies. By contrast, a commercial sample of TiN shows no gas sensing activity. Such devices are potentially scalable for everyday NO<sub>2</sub> detection and demonstrate that robust high-performance gas sensors based on inexpensive metal nitrides without precious metals are leading candidates for environmental monitoring technologies.