Ultrahigh Sensing Performance: Coresponse and Differentiation of Ethyl Acetate and Its Byproducts in Fe–Ce–O Interfacial Sensor

Accurately detecting low concentrations of ethyl acetate (EA) holds promise for the early screening of rectal and gastric cancer. The primary challenges lie in achieving a high response at parts per billion level concentration and ensuring high selectivity. This study focuses on designing Fe-Ce-O bimetallic oxides with doping and heterogeneous interfaces, which exhibit outstanding redox properties and highly enhanced ability of the adsorption and activation of both O₂ and EA molecules. Benefiting from the violent reaction between EA and the adsorbed oxygen species, the sensor achieves an ultrahigh ethyl acetate sensing response of more than 500,000 at 200 ppm concentration, along with an ultrafast recovery rate (<5 s). In experiments, the response can reach 4.8 even at an extremely low concentration of 10 ppb. Special attention is given to the interfacial chemical reactions through <i>in situ</i> DRIFTS during the sensing process. We propose for the first time that the produced intermediate byproducts (acetaldehyde, ethyl alcohol, acetic acid, and formic acid) coresponse on this sensor, contributing to its ultrahigh sensing response. Furthermore, both EA and the byproducts are effectively classified using linear discriminant analysis with 95% accuracy. This work is expected to elucidate the interfacial sensing mechanisms, particularly the contributions of derived byproducts to the sensor's response, and to propose a novel idea for designing high-performance sensors.