Three-dimensional In2O3–CuO inverse opals: synthesis and improved gas sensing properties towards acetone. Issue 62 (14th June 2016) - Xing, Ruiqing
Abstract : Specific three-dimensional inverse opal (3DIO) In2 O3 –CuO architecture with additional via-holes was first prepared by a simple sacrificial template method. Abstract : Specific three-dimensional inverse opal (3DIO) In2 O3 –CuO architecture with additional via-holes was first prepared by a simple sacrificial template method. Such specific nanostructures enable fast transport of gas molecules to the entire thin-walled sensing layers, which is very helpful for improving the sensing performance. Moreover, the mole ratio of Cu/In was controlled, ranging from 0–38.1% to adjust the hetero-contact amounts in the In2 O3 –CuO composites. The gas sensing properties of the as-prepared 3DIO In2 O3 –CuO samples were evaluated toward trace acetone, which is an important biomarker of diabetes in exhaled breath. The response of the 3DIO In2 O3 –CuO gas sensor with the best performance (with a mole ratio of Cu/In = 16.4%) was ∼14 to 5 ppm acetone, and had a calculated low detection limit of ∼30 ppb at 370 °C when R a / R g ≥ 1.2 was used as the criterion for reliable gas sensing. Besides, it also showed good selectivity, fast response ( τ res ) and recovery ( τ rec ) times, and stability. The enhanced gas sensing performance could be attributed to the hetero-contact effects between the different components and the specific 3DIO structure with the via-holes which provided a larger effective surface area for gas adsorption. It is believed that the as-prepared 3DIO sensor can be a promising ppb-level acetone sensor in various areas.