Synthesis of 1D SnO2 nanorods / 2D NiO porous nanosheets p-n heterostructures for enhanced ethanol gas sensing performance.

The microstructure and composition of materials have significant impacts on the gas sensing performance of sensors. In this work, a well-constructed 1D SnO 2 nanorods/2D NiO porous nanosheets heterostructure were successfully prepared for the detection of ethanol gas. The SnO 2 nanorods with a diameter of 10–15 nm uniformly grew on the surface of NiO nanosheets, increasing the number of active sites. The space charge region formed at heterointerfaces controlled electron transfer, benefiting for improving sensor response. Gas test results showed that, at the optimum operating temperature of 300 °C, NiO/SnO 2 (Ni:Sn = 1:0.5) reached a high response of 25.7 to 100 ppm ethanol, which was about 15 times higher than pure NiO (1.65). In addition, the NiO/SnO 2 displayed a fast response-recovery speed, good selectivity, and excellent long-term stability. The enhanced gas sensing mechanism of NiO/SnO 2 was proposed by analyzing the surface chemical states, surface area, and electronic structure of materials. • 1D SnO 2 nanorods/2D NiO porous nanosheets p-n heterostructures were synthesized. • The SnO 2 nanorods were grown on NiO porous nanosheets for the detection of ethanol gas. • The SnO 2 /NiO heterostructures showed the highest responses and fastest response/recovery speed. • The enhanced gas sensing mechanisms of SnO 2 /NiO were proposed. [ABSTRACT FROM AUTHOR]