High-performance hydrogen sulfide gas sensor based on gold-loaded mesoporous Co3O4 with ultralow detection limit

Reliable detection of highly toxic H2S in high-temperature industrial settings is of critical engineering value. Pristine Co3O4 sensors suffer from inherent drawbacks of insufficient sensitivity and poor selectivity for high-temperature H2S detection, while reported Co3O4-based composites fail to achieve efficient H2S detection at 200°C due to inadequate thermal stability or weak metal-support interaction. Herein, Au nanoparticle-modified mesoporous Co3O4 composites were synthesized via hydrothermal method and high-temperature calcination. Pristine Co3O4 served as the control, while Co3O4/Au samples with nominal Au loadings of 0.25%, 0.5%, and 1% were prepared, among which Co3O4/Au-0.5% showed the optimal H2S sensing performance. The elemental composition and surface chemical states of the prepared samples were examined using XPS in combination with other characterization techniques. The Co3O4/Au-0.5% sensor delivers optimal comprehensive performance: a 192.49% response to 100 ppm H2S, 20 ppb detection limit, response/recovery times of only 85 s/158 s, excellent selectivity against various common interfering gases, along with favorable repeatability and long-term operational stability. The improved sensing behavior mainly arises from Au-assisted oxygen spillover and interfacial electronic regulation at the Au-Co3O4 contact, highlighting the potential of this material design for H2S detection under elevated-temperature conditions.