The metal-oxide-based gas sensors show great potential in exhaled breath analysis owing to their simple, fast, and noninvasive characteristics. However, the exhaled breath contains moisture, and the surface-active sites of metal oxides are easily poisoned by water molecules, leading to degradation of the sensor performance, particularly the gas response and selectivity. Therefore, it is essential to develop oxide sensors that can reliably sense target gases over a wide humidity range without sacrificing the gas response. In this study, a facile strategy was proposed to incorporate hydrophobic La into an oxide sensor to simultaneously improve the humidity-stability and sensitivity of NH₃ detection for early prediction of kidney failure. WO₃ sensors doped with various concentrations of La were successfully synthesized, and their gas-sensing performances under various humid conditions were systematically investigated. Interestingly, a small amount of La doping (1 at. %) effectively prevented water poisoning and improved the gas response simultaneously. This sensor was able to selectively detect NH₃ up to 200 ppb with a limit of detection (LOD) of ∼780 ppt over a wide range of humidity. The concurrent enhancement in gas response and humidity-immunity was attributed to the surface hydrophobicity and increased specific surface area caused by the incorporation of La.

中文翻译：

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同时提高半导体金属氧化物传感器的抗湿性和气体响应的简单方法


基于金属氧化物的气体传感器由于其简单、快速和无创的特性，在呼气分析中显示出巨大的潜力。然而，呼出的气息中含有水分，金属氧化物的表面活性位点很容易被水分子毒害，导致传感器性能下降，尤其是气体响应和选择性。因此，必须开发氧化物传感器，该传感器能够在很宽的湿度范围内可靠地感应目标气体，而不会牺牲气体响应。在这项研究中，提出了一种简单的策略，将疏水性 La 整合到氧化物传感器中，以同时提高 NH₃ 检测的湿度稳定性和灵敏度，用于肾衰竭的早期预测。成功合成了掺杂不同浓度 La 的 WO₃ 传感器，并系统研究了其在各种潮湿条件下的气敏性能。有趣的是，少量的 La 掺杂 （1 at. %） 有效防止了水中毒，同时改善了气体反应。该传感器能够在较宽的湿度范围内选择性地检测高达 200 ppb 的 NH₃，检测限 （LOD） 为 ∼780 ppt。气体响应和湿度免疫力的同步增强归因于 La 的掺入引起的表面疏水性和比表面积增加。