Synergistic sensitization effects of single-atom gold and cerium dopants on mesoporous SnO2 nanospheres for enhanced volatile sulfur compound sensing

Abstract

The real-time monitoring of volatile sulfur compounds is indispensable; however, it continues to pose a significant challenge due to issues such as limited performance towards parts-per-billion (ppb)-level gas. Herein, a concept of synergistic sensitization effects involving single-atom gold (Au) and cerium (Ce) dopants is proposed to boost the sensing performance of allyl mercaptan, a common volatile sulfur compound. As a proof-of-concept, a chemiresistive gas sensor based on mesoporous SnO₂ nanospheres with single-atom Au decoration and Ce dopant (denoted Au/Ce–SnO₂) is successfully synthesized. The synthesis of Au/Ce–SnO₂ is achieved through the utilization of a self-template strategy, employing metal–phenolic hybrids as a precursor. The obtained materials exhibit high specific surface area (89.4 m² g⁻¹), and small particle size (∼86 nm). The gas sensor reveals unprecedented sensitivity (0.097 ppb⁻¹) and ultra-low detection limit (0.74 ppb), surpassing all state-of-the-art allyl mercaptan gas sensors. Furthermore, a wireless gas sensor is constructed for highly selective and real-time monitoring of allyl mercaptan. The decoration of single-atom Au facilitates the adsorption and dissociation of oxygen and target gases. Simultaneously, the Ce dopant enhances the oxidation of allyl mercaptan. The sensing performance is boosted by the mesoporous framework of SnO₂, as well as the synergistic sensitization effects resulting from single-atom Au decoration and Ce doping, thereby facilitating its potential application in environmental and health-related domains.