Pt Single-Atom-Induced Zn2SnO4/SnO2 Composite Surface Hydrophobic Reconfiguration for Triethylamine Sensing

Constructing high-performance gas sensors is of critical importance for environmental protection and human health. Functionalization with single-atom precious catalysts is considered an effective strategy to boost the sensitivity and selectivity of semiconductor gas sensors. Herein, a novel resistive gas sensor was developed using Pt single atoms anchored to Zn2SnO4/SnO2 composite for the ultra-sensitive detection of triethylamine (TEA). Hollow composite with amorphous Zn2SnO4 and nanocrystalline SnO2 (a-Zn2SnO4/c-SnO2) was obtained by calcining ZnSn(OH)6 precursor at 580 °C. With abundant dangling bonds and defect sites, the amorphous composite is inherently regarded as ideal anchoring carrier for single-atom catalysts. H2 treatment and subsequent impregnation in H2PtCl6 aqueous solution resulted in the anchoring of Pt single atoms on a-Zn2SnO4/c-SnO2 with oxygen vacancies (Pt-ZTO-Ov). Various characterization methods were employed to investigate the effect of Pt. The strong metal-support interaction between Pt and a-Zn2SnO4/c-SnO2 led to the increased oxygen vacancy content and electron transfer from a-Zn2SnO4/c-SnO2 to Pt. Additionally, Pt single atoms transformed the surface functional groups of the Zn2SnO4/SnO2 composite from hydrophilic to hydrophobic. Gas sensing tests revealed that Pt-ZTO-Ov showed high response (Ra/Rg = 665 to 100 ppm TEA) and rapid response time (1 s). Different from common performance degradation caused by humidity, response augmentation was observed for this hydrophobic Pt-ZTO-Ov-based TEA sensor under high humidity. The as-fabricated sensor can be used to preliminarily online monitor the freshness of the small grass goldfish over the decay period (0-12 hours). This work provides a solution for assessing seafood quality in the field of preservation.