Synergistic oxygen vacancy and Pt single-atom engineering in hollow SnO2 nanospheres for ultrasensitive ppb-level DMMP detection

Abstract

The critical need for detecting neurotoxic nerve agents (e.g., sarin) demands advanced vapor sensors. Herein, we develop Pt single-atom-decorated oxygen vacancy-rich SnO₂ hollow nanospheres (SnO₂/Pt-0.5) through synergistic material engineering for ultrasensitive dimethyl methylphosphonate (DMMP) detection. By combining characterization and theoretical calculations, the hollow nanosphere architecture was proved to accelerate gas diffusion and enrich target molecules via nanoconfinement, while Pt single atoms induce lattice distortion (evidenced by extended Sn–O bonds) to generate oxygen vacancies as primary adsorption centers and simultaneously enable catalytic spillover and electron donation to lower DMMP redox energy barriers. These synergies endow the SnO₂/Pt-0.5-based sensor to achieve excellent performance at 160 °C: a high response value (3.7), rapid response (17 s), a low actual detection limit of 15 ppb, and exceptional selectivity/stability, surpassing those of most reported metal-oxide-based DMMP sensors. By synergizing nanostructure engineering and atomic-level modulation, this work surmounts conventional sensing constraints, forging a transformative paradigm for chemical threat detection.