Low-Temperature-Enhanced and Ultrasensitive Exhaled H2S Gas Sensor Based on Cu2O-CuFe2O4 Nanoarrays

In this study, employing a 2D electrodeposition in situ assembly method, a high-performance H2S sensor based on a p-n type Cu2O-CuFe2O4 heterostructure ordered nanowire arrays was successfully fabricated on silicon substrates. Compared to Cu2O, Cu2O-CuFe2O4 nanowire arrays exhibits an ideal interfacial barrier structure and higher initial resistance, with a response to 10 ppm of H2S at room temperature (20 ± 3 °C) increased by 225 times and a response time reduced by over 2400 s. The sensor demonstrates exceptional sensitivity (LOD = 10 ppb; response = 234.5), selectivity, and humidity resistance (stable response ∼6000 to 10 ppm of H2S at 60–90% RH). Notably, it shows unique low-temperature-enhanced sensing, with a response of 8.365 × 104 to 10 ppm of H2S at −10 °C (vs 1.144 × 104 at 20 °C). The sensor was successfully applied to detect H2S in human oral exhaled breath, demonstrating its potential for noninvasive disease diagnosis and offering a promising approach for developing room-temperature breath analysis sensors.