2D electrodeposition assembly of Cu/Cu2O nanoarrays for low temperature H2S sensing

Ultra-sensitive hydrogen sulfide (H 2 S) detection technology at low temperatures provides critical support for the application of one-time alert systems under extreme conditions, ensuring reliable monitoring of H 2 S in low-temperature environments and enhancing safety and practicability. In this study, we developed a novel low-temperature H 2 S sensor based on Cu/Cu 2 O nanoarrays, prepared through a combination of 2D electrodeposition in situ assembly and the hydrothermal method. The heterointerface between Cu nanowires and Cu 2 O nanocubes presents a high barrier, which can be modulated to zero through the formation of continuous Cu x S conductive channels via the vulcanization reaction, thereby achieving excellent sensitivity and selectivity towards H 2 S at low temperatures. At freezing temperatures and low H 2 S concentrations (≤20 ppm), the sensors show ideal recovery and reasonable sensitivity (R=150 to 10 ppm H 2 S at 0 °C). However, the response significantly increases (R=5624 at 10 ppm H 2 S at 50 °C) and recovery is lost under reversed conditions. First-principles calculations have confirmed that the enhanced H 2 S adsorption at the heterointerface is the primary reason for the robust response observed at 0 °C. Experimental results demonstrate that the Cu/Cu 2 O nanoarrays were capable of rapid detection of H 2 S at low temperatures through modulation of heterointerface barriers.