HCHO Sensor Based on CuO@In₂O₃ Hollow Spheres Film for Lung Cancer Detection: Exploration of Superior Performance in High Humidity Environments

Formaldehyde (HCHO), a key marker of lung cancer, is found in the exhaled breath of patients. Detecting low concentration HCHO (In2O3hollow sphere and forming a heterojunction withIn2O3. The impact of CuO sputtering time on sensor performance was analyzed in detail. The sample with CuO sputtering time of 15 s exhibits the best performance. When the environment RH is 90%, 15-CuO@In2O3had a high response of 22.3 to 100 ppm HCHO and a 10 ppb detection limit. When the environmental RH increases from 10% to 90%, the response of sample 15-CuO@In2O3decreases with a decrease rate of about 27%, which is better than the decrease rate of sampleIn2O3(46.9%). The sensors also have good selectivity and long-term stability, meeting the needs for detecting formaldehyde in lung cancer patients’ exhaled breath. Its superior performance is ascribed to its large specific surface area, the interface effect of CuO on the band structure, and the synergistic catalytic effect. This work offers a new approach for developing high performance diagnostic sensors.