Highly Sensitive H₂ Sensors Based on Co₃O₄/PEI‐CNTs at Room Temperature

Abstract

The highly dispersed Co3O4 on the surface of CNTs modified with polyethylenimine (PEI) was synthesized using the hydrothermal method. In the CNT-Co3O4 composite materials, CNTs not only provide the substrate for the Co3O4 nanoparticles but also prevent their aggregation. Furthermore, the interaction between Co3O4 and CNTs modified with polyethylenimine (PEI) helps to improve the gas sensing performance. In particular, the CNT-Co3O4 composite synthesized at 190°C shows the outstanding sensitive characteristics to H2 with a lower detection limit of 30 ppm at room temperature. The obtained CNT-Co3O4 sensor displays excellent selectivity and stability to H2. The energy band model of the conductive mechanism has been built to explain the resistance change when the gas sensor is exposed to the H2. Hence, the CNT-Co3O4 composite material presents highly promising applications in H2 gas sensing.