The development of one-step deposition technology for metal oxide-based coatings is significant for the rapid fabrication of gas sensors. Gas sensors based on LaFeO₃ were fabricated by solution precursor plasma spraying (SPPS) strategy. Through a comparative analysis of material composition and cross-sectional morphology, we have determined the optimal spray distance (8 cm), ensuring the highest level of thickness uniformity in the coating (17.13 ± 0.34 μm). Furthermore, the influence of the number of passes on coating morphology and gas sensing performance was investigated. The optimal gas sensor possessed a higher response to isoamyl alcohol (236 at 25 ppm) at 250 °C. Meanwhile, excellent selectivity, repeatability, long-term stability (431.6 ± 9.2 at 60 ppm for 20 days), and a low limit of detection (144 ppb) were obtained. The superior low-concentration (< 25 ppm) gas-sensing performance should be ascribed to the loose porous morphology with uniform thickness and the higher surface activity of the optimal coating. Moreover, the practical experiment demonstrated the application potential of the sensors for monitoring wheat mildew. This work may provide a direction for the characteristic gas detection of wheat mildew and a successful case for the deposition of LaFeO₃ coating by SPPS.

金属氧化物基涂层一步沉积技术的发展对于气体传感器的快速制造具有重要意义。采用溶液前驱体等离子喷涂（SPPS）策略制备了基于LaFeO _{3 的气体传感器。}通过对材料成分和横截面形貌的比较分析，我们确定了最佳喷涂距离（8厘米），确保涂层厚度均匀性达到最高水平（17.13±0.34微米）。此外，还研究了遍数对涂层形貌和气敏性能的影响。最佳气体传感器在 250 °C 时对异戊醇（25 ppm 时为 236）具有更高的响应。同时，还获得了优异的选择性、重复性、长期稳定性（60 ppm，20 天为 431.6 ± 9.2）和低检测限（144 ppb）。优异的低浓度（< 25 ppm）气敏性能应归因于最佳涂层的疏松多孔形态、厚度均匀和较高的表面活性。此外，实际实验证明了该传感器在监测小麦霉变方面的应用潜力。该工作为小麦霉变特征气体检测提供了方向，也为SPPS沉积LaFeO _{3涂层提供了成功案例。}