Ultrasensitive H2S sensor based on Cu2O/Graphene heterostructures at room temperature

• Cu 2 O/graphene heterostructures are prepared by 2D electrodeposition in-situ assembly method. • The sensor exhibits a high response to 5-ppb H 2 S at room temperature. • The sensor still has a strong sensitivity at −20 °C. • User-friendly monitoring device realizes the real-time and fast detection of H 2 S. Technology development of low-concentration H 2 S sensing at low temperatures is of great significance for real-time surveillance of specific diseases and environment. In this work, a new Cu 2 O/graphene heterojunction sensor with an ideal interface is fabricated by 2D electrodeposition in-situ assembly method. The sensor is extremely selective to H 2 S and exhibits ultra-high H 2 S sensing properties at room temperature (R = 24125.785 % for 500 ppb H 2 S). Notably, the synergistic effects of barrier modulation and the sulfide reaction enable the sensor to detect H 2 S at concentrations as low as 5 ppb (R = 386 %) at 20 °C. Moreover, it exhibited good gas sensitivity even at temperatures as low as −20 °C (R = 71.26346 % for 100 ppb H 2 S). Furthermore, a sensor device was successfully manufactured for practical detection, which could be used for rapid detection of exhaled air and atmospheric monitoring. This work provides a new strategy for the design of high-sensitive and reliable room-temperature sensing materials for trace H 2 S gas detection.