Ultrasensitive Room-Temperature NO<sub>2</sub> Gas Sensor Based on MXene–Cu<sub>2</sub>O Composites
Wenbin Ren, Jinfeng Luan, Yin Liang, Huijuan Chen, Changchun Wang, Pinhua Zhang, Guangliang Cui, Li Lv
Abstract
The development of real-time trace-level NO 2 quantification platforms that can be operated at room temperature constitutes a critical advancement for occupational safety and public health monitoring systems. This study demonstrates a room-temperature NO 2 sensor using MXene–Cu 2 O composites prepared via a hydrothermal method. Systematic evaluation of MXene-introduced effects identified the 0.84 wt % MXene–Cu 2 O composite as optimal, exhibiting 4-fold enhanced sensitivity and shorter response (55 s)/recovery (35 s) time compared to pure Cu 2 O. Additionally, the sensor exhibits a low detection limit (10 ppb), high selectivity, great reversibility, and long-term stability. The enhanced sensing performance originates from precisely engineered interfacial architectures between MXene and Cu 2 O, which effectively adjust the charge-transfer behavior through the conduction tunnel in the sensing material. Furthermore, oxygen vacancy engineering creates defect-mediated adsorption centers that promote selective NO 2 chemisorption through charge polarization effects. This research offers a novel strategy for designing optimized structures to enhance the sensitivity of MOS-based materials for NO 2 gas detection.