Preparation of\nBiOI-Functionalized ZnO Nanorods for\nPpb-Level NO₂ Detection at Room Temperature

Abstract

Light activation is an effective method to improve sensor\nperformance\nat room temperature (RT). This work realized the effective detection\nof trace-level NO₂ at RT under visible light by combining\nZnO with the excellent photocatalyst BiOI. A 1.5 atom % BiOI–ZnO-based\nsensor under 520 nm light exhibited optimal sensing properties with\nthe maximum responses (13.9 to 1 ppm NO₂), fast response/recovery\ntime (66 s/47 s to 1 ppm), and a low detection limit of 25 ppb (theoretically\n0.34 ppb). In the meantime, the sensor also possessed excellent selectivity,\nrepeatability, and stability. The excellent properties were attributed\nto the high concentration of oxygen vacancies and the prolonged lifetime\nof photogenerated carriers. In addition, the observed photovoltaic\neffect of the sensor at RT indicated that the sensor held application\nprospects in the photovoltaic self-power field.