Incomplete Desorption-Induced Irreversible Response Property: The Intrinsic Challenge for Detection of Aliphatic Ketone Vapors by Co3O4.

Aliphatic ketones are widely used as solvents in industries because of their favorable solvency, while their inherent toxicity and flammability pose significant health and safety risks. However, the development of high-precision gas sensors for detecting aliphatic ketones remains significantly challenged by the indistinct reaction mechanism. Herein, Co3O4 with activating lattice oxygen (Co3O4-ALO) was prepared by a Mn2+-assisted hydrothermal method. The activation of lattice oxygen facilitates the formation of oxygen vacancies to drive surface redox, enabling a reversible and reproducible sensing response toward acetone. However, exposure to other aliphatic ketones resulted in incomplete recovery and progressive response attenuation during repeated measurements. Characterization of a series of Co3O4-ALO sensors (as prepared, after testing, and after regeneration) revealed that reaction intermediates or products were not completely desorbed from the sensor surface, and irreversible structural changes occurred during the ketone detection process. These findings demonstrate that the reversibility of Co3O4-ALO arises from the competition between surface redox reactions and the irreversible accumulation of oxidation intermediates accompanied by structural degradation. This study establishes the reason for the trade-off in sensing performance for detection of aliphatic ketone vapors by Co3O4 materials, providing vital theoretical guidelines for designing next-generation, highly reversible, and anti-poisoning gas sensors.