Perovskite oxide semiconductors have attracted tremendous interest in gas sensing due to their promising properties of tunable active sites, excellent catalytic ability and good structural stability. Nevertheless, the rapid synthesis of perovskite oxides and controlled regulation of their surface oxygen vacancies remains a great challenge. Herein, we report a novel metal–organic frameworks (MOFs) self-template strategy for the rapid and large-scale preparation of LaFeO₃ nanoparticles (M−LaFeO₃) with abundant oxygen vacancies. Benefit from the introduction of oxygen vacancies, the resultant M−LaFeO₃ gas sensor exhibit excellent formaldehyde (HCHO) sensing performance at a low operating temperature of 160 °C, including high sensitivity (R_g/R_a = 8.9 @ 100 ppm), fast response/recovery rate (53 s/32 s), low detection limit (1 ppm) and excellent selectivity. Comprehensive density functional theory (DFT) calculation and spectral characterizations reveal that oxygen vacancies play a vital role in promoting the adsorption and activation of O₂ and HCHO molecules, and accelerate the chemical reaction on the sensing materials surface. Most importantly, it proves the promising application of M−LaFeO₃ sensor in food safety assessment. This work not only provides a simple strategy for constructing oxygen vacancies enriched LaFeO₃, but also demonstrates the application potential of LaFeO₃-based gas sensors in the field of formaldehyde detection.

钙钛矿氧化物半导体由于其可调节活性位点、优异的催化能力和良好的结构稳定性等前景广阔的特性，在气体传感领域引起了极大的兴趣。然而，钙钛矿氧化物的快速合成及其表面氧空位的可控调节仍然是一个巨大的挑战。在此，我们报告了一种新型金属有机框架（MOF）自模板策略，用于快速大规模制备具有丰富氧空位的LaFeO ₃纳米粒子（M−LaFeO ₃）。得益于氧空位的引入，所得的M−LaFeO ₃气体传感器在160 °C的低工作温度下表现出优异的甲醛（HCHO）传感性能，包括高灵敏度（R_g /R _a  = 8.9 @ 100 ppm)、快速响应/回收率 (53 s/32 s)、低检测限 (1 ppm) 和出色的选择性。_{综合密度泛函理论（DFT）计算和光谱表征表明，氧空位对于促进O 2}和HCHO分子的吸附和活化、加速传感材料表面的化学反应起着至关重要的作用。_{最重要的是，它证明了M−LaFeO 3}传感器在食品安全评估中的良好应用前景。该工作不仅为构建富氧空位的LaFeO ₃提供了一种简单的策略，而且展示了LaFeO _{3的应用潜力。}基于气体传感器的甲醛检测领域。