Fe sites engineering unlocks selective chemiresistive sensing of n-propanol for breath-based lung cancer diagnostics

Abstract

Developing sensitive and cost-effective gas sensors for exhaled volatile organic compounds (VOCs) like n-propanol, a potential lung cancer biomarker, is challenging due to their low concentrations and the complex composition of in breath. While metal oxide semiconductors (MOS) like SnO₂ are stable and affordable, their limited sensitivity and poor selectivity hinder reliable sub-ppm VOCs detection. Here, we report a Fe sites-engineered SnO₂ nanoflowers (Fe-SnO₂ NFs) synthesized via self-templated pyrolysis strategy, overcoming limitations by optimizing its structural and electronic properties. Fe sites-engineering boosts surface reactivity and charge transport, enhancing selective n-propanol sensing. The Fe-SnO₂ NFs based sensor exhibits excellent sensing performance, with a response ratio of 1.9 at 5 ppb n-propanol, along with remarkable repeatability and long-term stability. Mechanistic insights indicate that Fe sites function as selective adsorption centers for n-propanol and concurrently boost the adsorption efficiency of neighboring Sn sites. Meanwhile, the hierarchical nanoflower architecture promotes efficient gas diffusion and intensified surface interactions. Moreover, validated using simulated exhaled breath samples, this work establishes Fe-SnO₂ NFs as a transformative platform for non-invasive, point-of-care lung cancer screening, bridging material innovation with clinical diagnostic needs.