Prepared gold-modified hollow nanosphere Co3O4/rGO composites for low concentration H2S gas detection

In this paper, Au-modified Co 3 O 4 hollow nanospheres/graphene composites (Au-Co 3 O 4 /rGO) were synthesized for the first time through a novel “one-pot cooking” method at ambient temperature. The hollow nanospheres exhibited a particle size of approximately 10–15 nm, while the modified Au nanoparticles were about 4–5 nm in diameter. A high-efficiency and high response H 2 S gas sensor was constructed based on Au-Co 3 O 4 /rGO ternary composites. The effects of different Au modifying mass ratios on the H 2 S gas-sensitive performance of the composites were systematically investigated. At an operational temperature of 92 °C, the Au-Co 3 O 4 /rGO sensor, incorporating an Au loading mass ratio of 1.3 wt%, exhibited a response value of 175.4 for H 2 S at 100 ppm, a recovery time of 30 s, and a detection limit reaching as low as 10 ppb. This response was tripled compared to the undoped Co 3 O 4 /rGO sensor. At the same time, the H 2 S sensing mechanism by Au-Co 3 O 4 /rGO was discussed in detail.