Heterovalent-doping-induced ultrasensitive and highly exclusive ethylene sensor: Application to crop quality inspection

Abstract

A promising ethylene sensor based on Sb₂MoO₆ (SMO) with a permeable lamellar structure and tunable W dopants is proposed. The optimal 5 mol% W-doped SMO featuring atomically distributed heterovalent doping sites enables the ideal combination of high response (121.26/2.6 for 10/0.5 ppm), short response/recovery time (180 s/54 s for 10 ppm), low limit of detection (LoD) (23.18 ppb), excellent selectivity, good long-term stability (45 days), and robust performance in high humidity (LoD of 31.5 ppb at 80 % relative humidity). The rich W⁴⁺ doping-induced active sites are primarily responsible for the strengthened gas-sensing performances. Theoretical simulations reveal that W doping modulates the SMO lattice through substitutional and interstitial mechanisms, optimizing adsorption energy and charge transfer between ethylene and Mo sites, thereby resolving the trade-off between high response and recovery speed. Furthermore, the real-world application in detecting and differentiating moldy rice across storage periods underscores its potential for on-site quality monitoring in the grain industry. This work highlights the significant role of heteroatom doping in tailoring material properties, positioning W-doped SMO as a highly effective gas-sensing material for agricultural and environmental applications.