Controllable synthesis of heterostructured CuO-NiO nanotubes and their synergistic effect for glycol gas sensing

The rapid development of p-type metal oxide semiconductors-based gas sensors for detecting glycol has recently attracted extensive attentions due to its huge hazard to human health. However, the poor sensitivity of the p-type gas sensor constraints its further application. In this work, novel p-p heterojunction CuO-NiO nanotubes have been controllably synthesized for high performance glycol gas sensors through one-pot synthesis approach combined with certain calcination treatment. In order to optimize element ratio of Cu to Ni for high performance gas sensors, the feeding ratio of Cu2+/Ni2+ in the synthesis process has been systematically studied. As a consequence, the gas sensor based on optimal hybrid nanotubes (CuO-NiO(13:7)) shows the highest sensitivity toward 100 ppm glycol at 110 degrees C with response/recovery time of 15 and 45 s. This hybrid sensor also shows excellent repeatability and long-term stability. The enhanced sensing properties to glycol are mainly attributed to the synergistic effects of CuO-NiO heterostructure and massively produced oxygen vacancies under the optimized element ratio of Cu to Ni. This work demonstrates the novel heterostructured CuO-NiO nanotubes have great potential for high performance gas sensor.