Acetone Gas Sensor Based on Spinel-Structured Hollow Sea Urchin-like Core–Shell ZnO/ZnFe2O4 Spheres

In this work, unique hollow sea urchin-like core–shell structured ZnO/ZnFe2O4 microspheres are synthesized by doping ZnO. Their effects on acetone gas are studied. The gas-sensitive materials are characterized by SEM, EDS, and XRD. The test results show that the sensor of ZnO-doped ZnFe2O4 exhibits excellent performance in detecting acetone gas. Among the four sensors, the ZnO/ZnFe2O4-6 sensor exhibits the best response to 100 ppm acetone gas at the optimal operating temperature of 250 °C, with a value of 94, which is four times higher than that of pure ZnFe2O4 sensors. In addition, ZnO modification reduces the sensor’s detection range for acetone to 50 ppb and greatly enhances its selectivity. Finally, we analyze the heterojunction structure of the composite material and its unique hollow core–shell structure, comprehensively studying the working principle and sensitization mechanism of the acetone gas sensor based on ZnO/ZnFe2O4.