The detection of volatile organic compounds (VOCs) such as triethylamine (TEA) is essential for maintaining air quality and human health. This study explores the synergistic effects of lanthanum (La) doping and the use of willow catkins as a template for the performance of SnO₂ gas sensors for TEA detection. The morphology and structure of the as-synthesized samples were investigated, and a series of experiments were conducted to explore the TEA sensing characterization of SnO2-based sensors. The results of gas sensing demonstrated that the response of La2-SnO₂ sensors is up to about 178 at 100 ppm TEA, showing a 45 % increase compared to pure SnO₂ with a detection limit as low as 5 ppb. The fabricated sensors demonstrated a rapid response time of 60 s and a recovery time of 98 s at 100 ppm TEA concentration. Moreover, the sensors showed stable and repeatable responses over multiple cycles, indicating excellent reproducibility and long-term stability. The enhanced TEA sensing performance can be attributed to the abundant oxygen vacancies and promising tubular structure, which not only offer more active sites to absorb oxygen species but also promote the adsorption-desorption process of gas molecules. This study highlights the potential of La-doped SnO₂ sensors fabricated using a sustainable willow catkins template as a promising candidate for practical TEA detection applications.