Hierarchical Porous In2O3/ZnO Heterojunctions with Oxygen Vacancy Enrichment for Ultrasensitive Ethylene Glycol
Jirui Lin1, Dan Li2,3, Litian Wang1
1Tianjin Key Laboratory of Film Electronic and Communication Devices, School of Integrated Circuit Science and Engineering, Tianjin University of Technology, Tianjin300384, PR China.
Abstract:
The growing demand for real-time monitoring of toxic ethylene glycol (EG) vapor in industrial safety and energy storage systems calls for high-performance gas sensors with superior sensitivity. Herein, hierarchically porous In2O3/ZnO heterojunctions were constructed by anchoring ZIF-8-derived ZnO onto nanoflower-like In2O3 through a low-temperature conversion strategy. The indium-containing precursor promoted ZnO crystallization at 350 °C, enabling mild heterojunction formation. The optimized In2O3-2ZnO exhibited the largest specific surface area, the highest concentration of oxygen vacancies, and a narrowed bandgap. Accordingly, In2O3-2ZnO delivered a response of 1077.92 ± 40.65 toward 20 ppm EG at 200 °C, with a theoretical detection limit of 105 ppb, excellent selectivity, good repeatability, and stable long-term performance. The enhanced performance originates from the combined effects of oxygen-vacancy-assisted oxygen activation and In2O3/ZnO interfacial electronic modulation, which strengthen EG adsorption and charge-transfer-induced resistance variation. The low ppb-level detection limit suggests its potential for early warning of EG leakage before hazardous accumulation in battery thermal management and industrial cooling systems.
