Specific Detection of Trace P-Xylene Gas by HKUST-1 Modified Terahertz Metasurface Sensor

P-Xylene is a prevalent indoor hazardous volatile organic compound (VOC). A long-term exposure limit of 100 ppm for p-xylene is generally recommended. Therefore, the sensitive and selective detection of trace p-xylene is crucial. This work presents a method for detecting p-xylene gas by combining terahertz (THz) metasurface sensor with a metal-organic-framework (MOF) material, copper benzene-1,3,5-tricarboxylate (HKUST-1). The sensor with double split ring resonators is fabricated using a micromachining process and characterized by a THz time-domain-spectroscopy (TDS) system. The test results are consistent with the simulation. Subsequently, the sensor’s surface is modified using the MOF material of HKUST-1 to enhance its sensitivity to the p-xylene gas. At room temperature, the sensitivity for p-xylene gas concentrations is between 1 and 100 ppm. The modified sensor has a maximum response frequency shift of 14 GHz for p-xylene gas at 100 ppm. Furthermore, the specificity, repeatability, and stability of the sensor are characterized. The proposed method for highly sensitive and specific detection of p-xylene gas has important reference significance for the development of other types of gas sensors.