Fabrication of three-dimensional flower-ball heterostructures MoS 2 /LDHs based on interface coupling strategy and their application in high-performance NO x gas sensing

Abstract

To address the core issues of high cost and low sensitivity in sensing gas, a three-dimensional flower-ball MoS2/LDHs sensitive material with rapid response to NOx was prepared by a facile hydrothermal method. While sensing NOx of 100 ppm, the sample MC-2 with a Co-Al molar ratio of 2:1 exhibits a response value of 28.31, whose response time is merely 2.13 seconds and detection limit is as low as 30 ppb. The unique morphological structure endows MC-2 with a specific surface area of 77.41 m 2 •g -1 , providing a substantial number of active sites for NOx adsorption. As indicated by XPS and EPR characterizations, abundant adsorbed oxygens and oxygen vacancy defects within the material synergetically promote the effective adsorption towards NOx, thus enhancing the material's response. Meanwhile, the formation of the p-p heterojunctions improves efficiency of electron transfer from LDHs to MoS2, ultimately augmenting the detection sensitivity of NOx.