Fabrication and Application of ZIF-8 Derived In2O3-ZnO Nanocomposites for Ultra-Sensitive NO2 Sensing under UV Irradiation at Room Temperature

Abstract

Nitrogen oxide (NO₂) is common by-products of industrial production, posing significant health risks to workers. Therefore, real-time monitoring of NO₂ is crucial. In this study, innovative In₂O₃-ZnO nano-materials were prepared by combining In₂O₃ with ZIF-8 via electrospinning, for detecting trace amounts of NO₂ at room temperature (RT). Compared to pure In₂O₃, the In₂O₃-ZnO nano-materials (V2) with a 10% weight ratio of ZIF-8 exhibited a significantly higher response (389.99) and a faster response time (16.9 s) to NO₂ under ultraviolet (UV) irradiation at RT. The superior gas sensing performance of the V2 nano-materials is attributed to the formation of n-n heterojunctions, enhanced optical absorption, increased oxygen vacancy ratio, and excellent dispersion among the nano-materials. The results demonstrate that V2 nano-materials can detect NO₂ at parts-per-billion (ppb) levels at RT, making them suitable for monitoring trace amounts of NO₂ in open environments. Furthermore, a portable real-time NO₂ monitoring device was constructed using V2 as the sensing material, an LM358-based amplifier circuit for data acquisition, an STM32F103C8T6 microcontroller as the main control unit, and a buzzer as an alarm device. Compared to devices using a helical Ni-Cr wire as an indirect heat source, this integrated NO₂ detection device offers real-time alarms with lower energy consumption. This application not only enhances worker health and safety in industrial environments but also demonstrates higher energy efficiency in practical application.