Highly Sensitive Ethylene Glycol Gas Sensor Based on MIL-68(In)@ZIF-8 Derivative

Abstract

Ethylene glycol, as a colorless and tasteless organic compound, is an important industrial raw material but can be hazardous to the environment and human health. Thus, the development of high-performance sensing materials is required for the monitoring of ethylene glycol. In this paper, a method to synthesize In₂O₃@ZnO using MIL-68(In)@ZIF-8 to serve as a sacrificial template is proposed for testing ethylene glycol sensing capabilities. For verifying an effective improvement in gas-sensitive performance by bimetallic organic skeleton (MOF) synthesized heterojunctions, we performed gas-sensitive tests on In₂O₃, ZnO, and In₂O₃@ZnO. In₂O₃@ZnO has the best sensitivity to ethylene glycol, including ultrahigh response value (20 ppm-200.12), moderate response/recovery time (53/50 s), and excellent selectivity. The construction of heterojunction is the main reason for enhancing the ethylene glycol response of the sensor. On this basis, the gas-sensitive enhancement mechanism of composites is analyzed. The results show that the design method of synthesizing heterojunctions using bis-MOFs proposes a new approach that enhances the properties of ethylene glycol.