Detection of Xylene Using Ni(OH)2-Enhanced Co3O4 Nanoplate via p-n Junctions

This study reports a novel Ni(OH)(2)/Co3O4 heterostructured nanomaterial synthesized through a simple two-step hydrothermal method combined with subsequent heat treatment. The Ni(OH)(2)/Co3O4 heterostructured nanomaterial showed excellent performance in the detection of xylene gas. XRD, SEM, and EDS characterized the crystal structure, microstructure, and composition elements of Co3O4 and Ni(OH)(2)/Co3O4, and the gas sensing properties of the Co3O4 sensor and Ni(OH)(2)/Co3O4 sensor were systematically tested. The test results indicate the Ni(OH)(2)/Co3O4 sensor has an optimal operating temperature of 175 degrees C, which is 10 degrees C lower than that of the Co3O4 sensor; has a response of 14.1 to 100 ppm xylene, which is 7-fold higher than that of the Co3O4 sensor; reduces the detection limit of xylene from 2 ppm to 100 ppb; and has at least a 4-fold higher response to xylene than other gases. The Ni(OH)(2)/Co3O4 nanocomposite exerts the excellent catalytic performance of two-dimensional nanomaterial Ni(OH)(2), solves the deficiency in the electrical conductivity of Ni(OH)(2) materials, and realizes the outstanding sensing performance of xylene, while the construction of the p-n heterojunction between Ni(OH)(2) and Co3O4 also improves the sensing performance of the material. This study provides a strategy for designing high-performance xylene gas sensors using two-dimensional Ni(OH)(2) materials.