School of Materials and Chemical Engineering, Xi'an Technological University, Xi'an, Shaanxi 710021, China.
Research Institute of Chemical Defense, Beijing 102205, China.
ACS Sens. 2024 Aug 23;9(8):4007-4016. doi: 10.1021/acssensors.4c00862. Epub 2024 Jul 30.
Achieving selective detection of ppb-level CO is important for air quality testing at industrial sites to ensure personal safety. Noble metal doping enhances charge transfer, which in turn reduces the detection limit of metal oxide gas sensors. In this work, metal-organic framework-derived Au-doped InO nanotubes with high electrical conductivity are synthesized by pyrolysis of the Au-doped metal-organic framework (In-MIL-68) as a template. Gas-sensing experiments reveal that the detection limit of 0.2% Au-doped InO nanotubes (0.2% Au, mass fraction) is as low as 750 ppb. Meanwhile, the sensing material shows a response value of 18.2 to 50 ppm of CO at 240 °C, which is about 2.8 times higher than that of pure InO. Meanwhile, the response and recovery times are short (37 s/86 s). The gas-sensing mechanism of CO is uncovered by in situ DRIFTS through the reaction intermediates. In addition, first-principles calculations suggest that Au doping of InO significantly enhances its adsorption energy for CO and improves the electron transfer properties. This study reveals a novel synthesis pathway for Au-doped InO nanotubular structures and their potential application in low concentration CO detection.
实现对 ppb 级 CO 的选择性检测对于工业现场的空气质量测试至关重要，以确保个人安全。贵金属掺杂可以增强电荷转移，从而降低金属氧化物气体传感器的检测限。在这项工作中，通过 Au 掺杂的金属有机骨架（In-MIL-68）作为模板热解，合成了具有高导电性的金属有机骨架衍生的 Au 掺杂 InO 纳米管。气敏实验表明，0.2% Au 掺杂 InO 纳米管（质量分数为 0.2% Au）的检测限低至 750 ppb。同时，该传感材料在 240°C 下对 50 ppm 的 CO 表现出 18.2 的响应值，约为纯 InO 的 2.8 倍。此外，响应和恢复时间较短（37 s/86 s）。通过原位 DRIFTS 揭示了 CO 的气敏机制，通过反应中间体。此外，第一性原理计算表明，Au 掺杂 InO 显著提高了其对 CO 的吸附能，并改善了电子转移性能。本研究揭示了一种新型的 Au 掺杂 InO 纳米管状结构的合成途径及其在低浓度 CO 检测中的潜在应用。
