One-dimensional hierarchical core-shell metal oxide semiconductor@WO 3 nanocomposites for Ppb-level acetone sensing

Detecting acetone is vital for both environmental safety and human health. However, many existing detection methods suffer from bulky equipment, complex processes, and limited efficiency. Metal oxide semiconductor (MOS) based gas sensors, particularly WO 3 , have gained attention due to their portability, cost-effectiveness, and sensitivity. In this study, we successfully synthesize a series of 1D hierarchical core -shell metal oxide semiconductor MOS@WO 3 structures (MOS: TiO 2 , WO 3 , and SnO 2 ) via a hydrothermal method employing selfassembly. Notably, the TiO 2 @WO 3 sensor exhibits an exceptional response value (R a /R g = 23.6) at a concentration of 50 ppm for acetone. It also demonstrates a rapid response recovery time (12/35.5 s) and a remarkably low detection limit, as low as 10 ppb (R a /R g = 1.29). This exceptional sensing performance is attributed to the large specific surface area, abundant oxygen vacancy, narrow bandgap, additional depletion layer of the heterostructure, and the main conduction channel in the shell of TiO 2 @WO 3 NCs. This study not only promotes acetone sensor development but also contributes to innovative layered core -shell material fabrication methodologies.