Three-dimensional ordered ZnO–Fe3O4 inverse opal gas sensor toward trace concentration acetone detection

Abstract

Three-dimensional inverse opal (3DIO) ZnO-Fe3O4 composite structure was prepared by a template method and the gas sensing property was investigated toward trace acetone which is an important biomarker of diabetes. The prepared 3DIO composite sensors have large surface area due to both macropores (larger than 100nm) and mesoporous structure in skeleton, which make the inner surface accessible and provide more active sites to adsorb more oxygen species and target molecules. 3DIO ZnO-Fe3O4 composite sensor exhibits much higher response toward acetone relative to pure ZnO sensor. The optimal 3DIO sensor exhibited a detection limit as low as 100ppb acetone and showed 40% response increase from 0.9ppm (healthy humans) to 1.8ppm (diabetics) which allow reliable diagnosis of diabetic patients by acetone monitoring.