Highly sensitive H₂S sensors based on Cu₂O/Co₃O₄ nano/microstructure heteroarrays at and below room temperature

Gas sensors with high sensitivity at and below room temperature, especially below freezing temperature, have been expected for practical application. The lower working temperature of gas sensor is better for the manufacturability, security and environmental protection. Herein, we propose a H₂S gas sensor with high sensitivity at and below room temperature, even as low as -30 °C, based on Cu₂O/Co₃O₄ nano/microstructure heteroarrays prepared by 2D electrodeposition technique. This heteroarray was designed to be a multi-barrier system, and which was confirmed by transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy and scanning probe microscopy. The sensor demonstrates excellent sensitivity, sub-ppm lever detection, fast response, and high activity at low temperature. The enhanced sensing property of sensor was also discussed with the Cu₂O/Co₃O₄ p-p heterojunction barrier modulation and Cu₂S conductance channel. We realize the detection of the noxious H₂S gas at ultra-low temperature in a more security and environmental protection way.