Solvent-Dependent Synthesis of Okra-Shaped Co3O4 for Acetone Gas Detection at Low Operation Temperatures

In this work, Co3O4 samples with controllable morphology were successfully synthesized via a one-pot hydro-thermal method by altering the added volume ratio of ethanol to water (R-E/W). The okra-shaped porous Co3O4 was obtained with a ratio of 1:1 (R-E/W = 16.5/16.5). Additionally, the sensors fabricated with the as-prepared Co3O4 samples based on various ratios of ethanol to water were investigated to figure out their sensing performance. The okra-shaped Co3O4 sensors exhibited the highest response value of 35.2 to 100 ppm acetone at 150 degrees C, with the response/recovery time of 109/42 s and its limit of detection was as low as 30 ppb. The excellent acetone sensing performance of the okra-shaped Co3O4 sample can be mainly attributed to high utilization of the exposed active sites and the extensive chemically adsorbed oxygen species due to the highest specific surface area. By and large, the okra-shaped porous Co3O4 has great potential in sensing acetone, adjusting the composition of the solution was feasible for controlling the morphology of the sensing material.