Enhanced Gas‐Sensing Performances of Ru‐Loaded p‐Type Co 3 O 4 Nanoparticles

Co 3 O 4 nanoparticles (NPs) and Co 3 O 4 NPs‐functionalized with 0.25, 0.50, and 1.00 wt.% Ruthenium (Ru) are synthesized by the precipitation and impregnation methods. X‐ray diffraction data confirm that all samples are highly crystalline with a typical cubic Co 3 O 4 NPs structure. Electron microscopic images show spherical morphologies of Co 3 O 4 nanoparticles with the diameters of 10–30 nm and Ru nanoparticles with relatively small diameters of 2–4 nm loaded on Co 3 O 4 surfaces. The gas‐sensing results reveal that Ru loading at an optimally low Ru content of 0.25 wt.% led to significantly enhanced ethanol sensing performances. Specifically, the 0.25 wt.%Ru/Co 3 O 4 sensor exhibits a good p‐type response of ≈30 to 100 ppm C 2 H 5 OH, short response time (0.08 s), good recovery time (a few minutes) and high C 2 H 5 OH selectivity against H 2 S, H 2 , NH 3 , NO 2 , and SO 2 . Therefore, the Ru‐loaded Co 3 O 4 sensor is a promising alternative p‐type gas sensor for ethanol detection.