UV-activated In₂O₃-decorated ZnO gas sensor with fully recoverability for ppb-level NO₂ detection

One-dimensional metal oxide semiconductors exhibit a large specific surface area and broad interaction zone over cross-section area, which significantly enhances the gas sensitivity toward target gas. However, the strong chemisorbed gas molecules hinders the desorption process at room temperature, resulting in the irreversible sensing performances. The reversible sensing performance can be obtained under higher working temperature, but the additional heating unit limits the integration of sensors. In this work, to further improve the reversibility and sensing response capability of pristine ZnO-based NO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> sensors at room temperature, the synergistic strategy of enhancing activation energy through highly-activated photocarriers and one-dimensional heterojunction construction were proposed to exploit an ultraviolet-assisted NO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> sensor based on In<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>@ZnO nanofiber. The fabricated NO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> sensor presented remarkable detection limit (2 ppb), selectivity (at least 7.4 times higher than other interfering gases), repeatability (relative variation < 2%), and fully recoverability. This work proposes an effective strategy on ppblevel NO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> detection with fully recoverability.