Co 3 O 4 nanoparticle decorated ZnO nanorods for high-sensitivity acetone detection

Abstract A MEMS-based gas sensor was developed using hydrothermally grown ZnO nanorods (ZnONRs) decorated with Co 3 O 4 nanoparticle (Co 3 O 4 NP) to improve sensitivity. The ZnO nanorods, synthesized on a SnO 2 layer, offer a high surface-to-volume ratio that facilitates efficient gas adsorption, while the Co 3 O 4 NP enhance the concentration of adsorbed oxygen, further promoting gas molecule interactions. Gas sensing results show that the Co 3 O 4 NP decorated ZnONRs sensor achieves the response of 80.1% to 1 ppm acetone at 310 °C, outperforming 63.1% of pristine ZnONRs sensor under the same condition. The device operates effectively across an acetone concentration range of 0.1–10 ppm and exhibits stable, repeatable responses with excellent selectivity toward acetone compared to other tested gases.