Ultra-trace chlorinated gases optical sensor with moisture-resistant based on structural-customizable UiO-66 3D photonic crystals

Abstract

Chlorinated gases seriously pollute the environment and threaten human health. Limitation of insufficient adsorption sites and interference of atmospheric humidity, designing an advanced sensing device with high adsorption and moisture resistance is still a challenge to detect chlorinated gases for air monitoring. Herein, a moisture-resistant optical sensor based UiO-66 three-dimensional (3D) photonic crystals is achieved. The optical sensor shows customizable structure and tunable optical properties, which are benefit to gas diffusion and signal transduction. The application of the optical sensor for 2.5 ppm carbon tetrachloride (CCl4), dichloromethane (CH2Cl2), chlorobenzene (C6H5Cl) and hydrochloric acid (HCl) detection was investigated in relative humidity (RH) 35%. The sensor exhibits excellent selectivity for HCl, which agree with the density functional theory (DFT) calculations for the adsorption energy. Especially, the sensor exhibits high stability and repeatability under RH 50%− 95%, and the sensing performance of the sensor for 2.5 ppm HCl has improved at RH up to 65%, limit of detection (LOD) can reach 10.9 ppb, ultra-fast response was 0.49 s. The improvements in sensing performance under RH are attributed to moisture-enhanced adsorption mechanism. This work provides a new insight for effective utilization of advanced materials and device to achieve ultra-trace chlorinated gas detection in humid atmosphere.