A protective oxide strategy for stable graphene gas sensors

Graphene is an exceptional transducer for chemical sensing owing to its two-dimensional structure and distinctive electronic properties. However, coupling graphene to noble-metal catalysts remains intrinsically challenging: catalytic oxygen dissociation, essential for sensing many gases and volatile analytes, produces reactive oxygen species that irreversibly oxidize graphene and degrade device performance. Here we overcome this limitation with a heterostructure architecture that spatially decouples catalytic activation from the graphene conduction channel, demonstrated for CO sensing. An ultrathin Sb₂O₃ interlayer inserted between CVD graphene and a platinum catalyst serves as a chemically inert barrier that suppresses oxidative attack while maintaining charge-transfer-based transduction. The resulting Pt/Sb₂O₃/graphene devices deliver reproducible CO sensing during prolonged heating, in ozone-rich atmospheres and after 20 months of ambient storage. This architecture provides a general route to stable catalyst-integrated graphene gas sensors.