Abstract A novel synthesis of In2O3 porous microcolumnar structures (MCs) by a self-sacrificial template route was carried out using MIL-68. Using a modified calcination strategy, the samples could maintain the original metal organic frame work (MOF) morphology with a high gas accessibility after a slow decomposition of organic ligands. Pt nanoparticles (NPs) were loaded on the samples before or after the MOF calcination, leading to different contact states of the Pt NPs and In2O3 matrix. The gas sensing properties of the samples were systematically investigated using a dynamic testing system. Particularly, sample Pt/In2O3 MCs-1 exhibited a superior NO2 sensing performance near room temperature (Rg/Ra = 44.9 at 1 part-per-million and 5.2 at 100 parts-per-billion (ppb)). The sensor resistance could recover to its baseline even at 40 °C after purging with air without any additional treatment. This can be attributed to the chemical sensitisation of the Pt NPs as well as large contents of pores and channels for gas diffusion. The introduction of humidity in the gas mixture could remarkably decrease the sensor response and recovery times owing to the ‘wet’ NO2 adsorption mechanism. This study demonstrated a novel synthesis route of Pt-loaded In2O3 porous columnar structures and its potential applications in near-room-temperature detection of ppb-level NO2.

中文翻译：

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金属有机框架衍生的 In2O3 微柱状结构嵌入 Pt 纳米粒子，用于在室温附近检测 NO2

摘要 使用 MIL-68 通过自牺牲模板路线合成了 In2O3 多孔微柱结构 (MCs)。使用改进的煅烧策略，样品可以在有机配体缓慢分解后保持原始金属有机骨架 (MOF) 形态，并具有高气体可及性。在 MOF 煅烧之前或之后，将 Pt 纳米粒子 (NPs) 负载在样品上，导致 Pt NPs 和 In2O3 基质的不同接触状态。使用动态测试系统系统地研究了样品的气敏特性。特别是，样品 Pt/In2O3 MCs-1 在接近室温时表现出优异的 NO2 传感性能（Rg/Ra = 44.9 在 1 ppm 时和 5.2 在 100 ppb 时）。即使在 40 °C 下用空气吹扫后，传感器电阻也可以恢复到其基线而无需任何额外处理。这可归因于 Pt NPs 的化学敏化以及用于气体扩散的大量孔隙和通道。由于“湿”NO2 吸附机制，在气体混合物中引入湿气可以显着降低传感器响应和恢复时间。本研究展示了载铂 In2O3 多孔柱状结构的新合成路线及其在近室温检测 ppb 级 NO2 中的潜在应用。由于“湿”NO2 吸附机制，在气体混合物中引入湿气可以显着降低传感器响应和恢复时间。本研究展示了载铂 In2O3 多孔柱状结构的新合成路线及其在近室温检测 ppb 级 NO2 中的潜在应用。由于“湿”NO2 吸附机制，在气体混合物中引入湿气可以显着降低传感器响应和恢复时间。本研究展示了载铂 In2O3 多孔柱状结构的新合成路线及其在近室温检测 ppb 级 NO2 中的潜在应用。