Design of a ppb-level Gas Sensor Based on Hollow Nanosphere Structures for H 2 S Detection in Aerospace Environments

Abstract

Detecting hydrogen sulfide (H 2 S) is crucial for aerospace applications, as it is commonly present in planetary soils. However, the vacuum conditions encountered in aerospace, characterized by ultra-low pressure and oxygen scarcity atmospheres, pose significant challenges for conventional sensors. In this work, we report the design and fabrication of a ppb-level H 2 S gas sensor based on hollow CuO-SnO 2 nanosphere structures (~200 nm). Remarkably, the sensor achieves reliable detection of H₂S at concentrations as low as 50 ppb, even under high-vacuum conditions (3 × 10 -3 Pa).Moreover, it maintains stable sensing performance from room temperature (25℃) down to sub-zero environments (-40°C), with responses of 464.6 and 3.9 toward 5 ppm H 2 S, respectively. Unlike conventional sensors that rely on oxygen vacancies and require ambient oxygen to function, our sensor exploits a direct chemical reaction between CuO and H 2 S, enabling efficient operation in oxygen-free vacuums. The hollow nanosphere architecture enhances gas adsorption, while built-in p-n heterojunction provides charge modulation independent of oxygen. This synergistic structural and electronic design delivers ppb-level H 2 S sensing under extreme vacuum, positioning CuO-SnO 2 nanospheres as a versatile platform for gas sensing in both ambient and aerospace environments.