Detection of Xylene Using Ni(OH) 2 -Enhanced Co 3 O 4 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 °C, which is 10 °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. [ABSTRACT FROM AUTHOR]