Design of NiCo2O4@SnO2 heterostructure nanofiber and their low temperature ethanol sensing properties

Hybrid one-dimensional nanomaterials with hierarchical structure have received a great deal of attention as sensing materials due to their high surface area, excellent catalytic performance, and robust structures. Novel NiCo2O4 nanofibers-decorated SnO2 nanosheets are synthesized by a two-step electrospinning and hydrothermal methods. The like NiCo2O4@SnO2 composite-based sensor exhibits the highest sensitivity to ethanol (8.87 at 100 ppm) at a low working temperature of 160 °C. Also, the NiCo2O4@SnO2 composite-based sensor demonstrates short response/recovery time, excellent selectivity and long stability for the detection of ethanol gas. Importantly, compared with the pristine NiCo2O4 nanofibers, the sensor based on NiCo2O4@SnO2 composites can be improved approximately 8 times that of the former. Moreover, the sensor based on NiCo2O4@SnO2 composites shows excellent stability and repeatability and low detection limits (approximately 5 ppm). As a result, such one-dimensional hierarchical structure with effective p-n heterojunction and large specific surface area would display excellent electron transport property.