Highly sensitive acetone sensor based on ZnFe2O4/ZnO hollow core–shell nanospheres

The detection of acetone holds significant importance for both non-invasive diabetes screening and industrial safety monitoring. In this work, novel ZnFe 2 O 4 /ZnO hollow core-shell nanospheres were synthesized via a two–step hydrothermal method for acetone detecting. The sensor performance was optimized by precise control the film thickness. Compared with pure ZnO and other samples, ZnFe 2 O 4 /ZnO with the optimal shell thickness exhibited superior acetone sensing performance, showing a response of 38.1 toward 100 ppm acetone at a lower operating temperature of 200 °C, which is more than three times higher than that of pure ZnFe 2 O 4 . The sensor also demonstrated excellent selectivity, rapid response and extremely low detection limit (0.08 ppm). The improved acetone sensing performance is attributed to the synergistic effect of heterojunction and the highly active Zn-terminated surfaces. Optimizing the ZnO shell thickness balances gas diffusion with maximized active surface exposure, thereby fully utilizing both mechanisms for superior sensitivity.