Rapid and Efficient NO 2 Sensing Performance of TeO 2 Nanowires.

Gas sensors play a pivotal role in environmental monitoring, with NO 2 sensors standing out due to their exceptional selectivity and sensitivity. Yet, a prevalent challenge remains: the prolonged recovery time of many sensors, often spanning hundreds of seconds, compromises efficiency and undermines the precision of continuous detection. This paper introduces an efficient NO 2 sensor using TeO 2 nanowires, offering significantly reduced recovery times. The TeO 2 nanowires, prepared through a straightforward thermal oxidation process, exhibit a unique yet smooth surface. The structural characterizations confirm the formation of pure-phase TeO 2 after the anneal oxidation. TeO 2 nanowires are extremely sensitive to NO 2 gas, and the maximum response (defined as the ratio of resistance in the air to that under the target gas) to NO 2 (10 ppm) is 1.559. In addition, TeO 2 nanowire-based sensors can return to the initial state in about 6-7 s at 100 °C. The high sensitivity can be attributed to the length-diameter rate, which adsorbs more NO 2 to facilitate the electron transfer. The fast recovery is due to the smooth surface without pores on TeO 2 nanowires, which may release NO 2 quickly after stopping the gas supply. The present approach for sensing TeO 2 nanowires can be extended to other sensor systems as an efficient, accurate, and low-priced tactic to enhance sensor performance.