The toxicity of SO₂ is well known, so real-time monitoring of SO₂ concentration is critical. Monitoring SO₂ in industrial flue gas requires specially designed sensors to adapt to the complex application environment. In this study, a YSZ-based impedancemetric SO₂ sensor was proposed and tested using non-stoichiometric La_xCuO_4-δ (x=1.7, 2, 2.3) sensing electrode (SE) prepared by impregnation method. The sensor displays excellent sensing performance to 25-500 ppm SO₂ with phase angle (Θ) as the response signal. By adjusting the deficiency or excess of La site in the LaCuO₄, more oxygen vacancies are successfully formed, thereby improving the catalytic activity and adsorption performance to SO₂, enhancing the sensitivity of the sensor. Compared with La₂CuO₄-SE (sensitivity 7.03 °/decade), the sensitivities of sensors based on La_1.7CuO_4-δ-SE (9.37 °/decade) and La_2.3CuO_4-δ-SE (7.86 °/decade) are significantly improved at 550°C. The sensor based on La_1.7CuO_4-δ-SE displays the highest sensitivity and good long-term stability. The effect of 300 ppm H₂S, CH₄, CO₂, H₂, NH₃ or NO₂ on response signal ΔΘ of the sensor to 300 ppm SO₂ is 11.4%, -2.6%, -8.0%, -0.6%, 6.6% and -7.2%, respectively, showing good anti-interference ability. However, O₂ and humidity interference needs to be calibrated in advance.

中文翻译：

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一种基于非化学计量 La2CuO4 传感电极的新型基于 YSZ 的阻抗 SO2 传感器


SO₂ 的毒性是众所周知的，因此实时监测 SO₂ 浓度至关重要。监测工业烟气中的 SO₂ 需要专门设计的传感器，以适应复杂的应用环境。本研究提出了一种基于 YSZ 的阻抗式 SO₂ 传感器，并使用浸渍法制备的非化学计量 La_xCuO_4-δ （x=1.7， 2， 2.3） 传感电极 （SE） 进行了测试。该传感器在以相位角 （Θ） 作为响应信号时，对 25-500 ppm SO₂ 表现出出色的传感性能。通过调整 LaCuO₄ 中 La 位点的缺乏或过量，成功形成更多的氧空位，从而提高对 SO₂ 的催化活性和吸附性能，增强传感器的灵敏度。与 La₂CuO_4-SE （灵敏度 7.03 °/decade） 相比，基于 La_1.7CuO_4-δ-SE （9.37 °/decade） 和 La_2.3CuO_4-δ-SE （7.86 °/decade） 的传感器在 550°C 时的灵敏度显著提高。 基于 La_1.7CuO_4-δ-SE 的传感器具有最高的灵敏度和良好的长期稳定性。300 ppm H₂S、CH₄、CO₂、H₂、NH₃ 或 NO₂ 对传感器响应信号 ΔΘ 对 300 ppm SO₂ 的影响分别为 11.4%、-2.6%、-8.0%、-0.6%、6.6% 和 -7.2%，表现出良好的抗干扰能力。但是，O₂ 和湿度干扰需要提前校准。