Interface-driven modulation of surface oxygen species in Au-decorated Co3O4 nanosheets for ethanol sensing

초록

The modulation of surface oxygen species is a critical factor governing the gas-sensing behaviors of transition metal oxides. In this study, Au-decorated Co3O4 nanosheets were synthesized to investigate the influence of metal-oxide interfacial interactions on surface oxygen chemistry and ethanol sensing performance. Introducing Au nanoparticles induced interfacial charge redistribution between Au and Co3O4, thereby reconstructing the surface oxygen species, including an increase in chemisorbed oxygen and oxygen vacancy-related sites. Therefore, the ethanol oxidation reaction on the sensor surface was strongly promoted. Gas sensing measurements revealed that the sensor containing the optimized Au loading exhibited the highest response to ethanol, unlike pristine Co3O4. This improved sensing performance can be attributed to the synergistic effect of interfacial electronic modulation and enhanced surface oxygen activity. However, excessive Au loading only partially covered the Co3O4 surface, thus reducing the number of accessible reactive sites and decreasing response. This study highlights the importance of interfacial electronic interactions in controlling the surface oxygen chemistry of metal oxides and clarifies the rational design of high-performance gas sensors through interface engineering.

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