Wide‐Range Adaptive Metal Oxide for Hydrogen Sulfide Detection From Earth to Space‐Like Environments

ABSTRACT Chemiresistive gas sensors based on semiconducting metal oxides for toxic gas detection are widely explored for terrestrial applications under ambient environments, but their potential in extraterrestrial applications remains underexplored. Herein, we developed porous Cu‐doped SnO ₂ microspheres, enabling high sensitivity and selectivity toward hydrogen sulfide (H ₂ S), from the ambient air (25°C, 10 ⁵ Pa) to extreme conditions (−40°C, ∼10 ^{− 4} Pa) designed to simulate the space‐like oxygen defects and cryogenic environments. Hierarchical porosity enables efficient gas diffusion across pressure regimes, and Cu ^{2 +} doping and oxygen vacancies thus enable oxygen‐independent chemisorption. Moreover, in situ‐formed chemical adsorption promotes interfacial charge transfer, which exhibits partial reversibility. The semi‐quantitative framework represented by a CuS kinetic proxy, combining numerical simulations based on Wolkenstein adsorption theory, finite element methods, and experimental results, reveals a dual‐mechanism paradigm. At ambient conditions, the oxygen‐adsorption‐driven redox reaction is dominant. In contrast, under a vacuum around 10 ⁻⁴ Pa, direct chemisorption and interfacial charge transfer primarily govern the gas adsorption responses. This study offers a generalized metal‐oxide platform for gas detection for future space exploration and life‐support monitoring systems.