As a typical n-type semiconductor, InO is often used in gas sensors due to the wide band gap, adjustable morphology and good electrical conductivity. However, the pristine InO has some disadvantages, such as higher operating temperature, poor sensing performance to low concentrations of gases. In this work, we fabricated flower-like NiO/InO composites via a facile one-pot hydrothermal method, and investigated their gas sensitivity to various concentrations of NO at different temperatures. The responses (R/R) of NiO/InO-0.2 composite to 0.1–80 ppm NO are 2.5 ∼ 5.8 times higher than those of pristine InO at the optimum temperature of 150 °C, respectively. The room-temperature response of the NiO/InO-0.2 composite to 20 ppb NO is 1.82 with the limit of detection (LOD) of 5 ppb, indicating great application potential for NO detection. Moreover, the NiO/InO-0.2 composite has the excellent reproducibility, good long-term stability and selectivity. The specific morphology with larger surface area and the formation of p-n heterojunction synergistically enhance the sensing properties of NiO/InO composite, demonstrated by DFT calculation and experiments. This work provides a facile fabrication of flower-like InO–based composites for room-temperature detection of ppb-level NO.

中文翻译：

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轻松制备花状 NiO/In2O3 复合材料，用于在室温和较低温度下灵敏、选择性地检测 NO2


InO作为典型的n型半导体，由于具有宽带隙、形貌可调和良好的导电性，常用于气体传感器。然而，原始InO存在一些缺点，例如工作温度较高、对低浓度气体的传感性能较差。在这项工作中，我们通过简单的一锅水热法制备了花状 NiO/In2O 复合材料，并研究了它们在不同温度下对不同浓度 NO 的气体敏感性。在最佳温度 150 °C 下，NiO/InO-0.2 复合材料对 0.1~80 ppm NO 的响应（R/R）分别是原始 InO 的 2.5~5.8 倍。 NiO/InO-0.2复合材料对20 ppb NO的室温响应为1.82，检测限（LOD）为5 ppb，表明NO检测具有巨大的应用潜力。此外，NiO/InO-0.2复合材料具有优异的重现性、良好的长期稳定性和选择性。 DFT计算和实验证明，具有较大表面积的特定形貌和pn异质结的形成协同增强了NiO/InO复合材料的传感性能。这项工作提供了一种简单的花状 InO 基复合材料的制备方法，用于室温检测 ppb 级的 NO。