Highly Sensitive and Selective n-Butanol Sensor Based on NiO Nanosheet/Bulk ZnSnO₃ p-n Heterojunction

In this study, the NiO/ZnSnO3 composite was prepared by a hydrothermal method. Its microstructure, morphology, chemical composition, size, and specific surface area were characterized, and its gas-sensing properties were tested. The results showed that the bulk ZnSnO3 in the composite adhered tightly to the surface of the flake-like NiO, the composite having an increased specific surface area. Its main elements were Ni, O, Zn, and Sn. The NiO/ZnSnO3 composite prepared with a NiO content of 10 wt% had the best sensing properties to n-butanol gas, with an optimal operating temperature of 350 degrees C, the same as that of pure ZnSnO3. The sensor response of the composite to 100-ppm n-butanol gas was 2467.10, which was 868.09 times that (2.842) to ammonia, 1.44 times that (1707.44) to acetone, 17.37 times that (142.04) to methanol, 41.89 times that (58.89) to formaldehyde, and 1.61 times that (1527.86) to ethanol. The composite showed excellent repeatability and good long-term stability. For all the remarkable properties above, the NiO/ZnSnO3 composite has broad application prospects in detecting n-butanol gas.