The distinguished hydrogen sensibility by selecting diameters of single-walled carbon nanotubes and adding sensitive materials

Hydrogen sensors based on palladium (Pd)/semiconducting single-walled carbon nanotube(s-SWNTs) have showed great performance in sensitivity, limit of detection (LOD), and response time. With the development of research, it is proved that diameters and chirality of s-SWNTs strongly influence the detection. In this paper, we fabricated two kinds of sensors with different diameters, and that results showed response of sensor with 0.7–1.2 nm s-SWNTs was almost 6 times higher than that of the one with 1.2–1.6 nm s-SWNTs. The former could achieve the response of change ≈6.09 for 1 ppm H2 in N2, and the latter was ≈1.07. Furthermore, with Pd/HKUST-1 as functionalization for capturing more hydrogen (H2), the system formed a synergistic effect to enhance the change of resistance. The fabricated Pd/HKUST-1/s-SWNTs film (0.7–1.2 nm) H2 sensor presents a very fast recovery time of 8 s at 10 ppm and a detection limit of 1 ppm H2 in nitrogen(N2). In addition, in the air the sensor can also work. Its response time of the sensor to 0.05% H2 in air are 0.183 s. By choosing the diameter of s-SWNTs and adding H2-sensitive materials, the sensors are expected to achieve the fast response and recovery with high sensitivity and low LOD.