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[Display omitted] • Porous and hollow 1D SnO 2 /Zn 2 SnO 4 composites are prepared by electrospinning. • UV light enhanced excellent TEA gas-sensing property can be primarily observed. • Greatly reduced working temperature of 120 °C and superior selectivity are gained. • Good practicality of gas sensors for food spoilage evaluation is valuable. • Enhanced mechanism is derived from the accelerated surface electron migration. Porous and hollow SnO 2 /Zn 2 SnO 4 composites with typical one-dimensional (1D) structure have been synthesized by adjusting the amounts of 2-methylimidazole zinc salt (ZIF-8) added in the precursor solution through a modified electrospinning technology. Compared with the gas-sensing performance of different samples detected in the normal condition, it is confirmed that the optimal working temperature can be markedly decreased from 260 to 120 °C under UV light irradiation, along with the substantially improved gas selectivity. In addition, SnO 2 /Zn 2 SnO 4 heterostructures exhibit a higher response (increases from 1.7 to 2.8) and faster response/recovery times (decreases from 24/154 to 14/42 s) to triethylamine (TEA) than that of the pure SnO 2. Significantly, the good practicality of gas sensors for food spoilage evaluation could be testified by effectively detecting the gas released during the putridity of prawns. UV light enhanced surface electron migration mainly contributes to the elevated synergistic effect between the formation of n-n heterojunction and tunable surface/interface electron transport behavior, as well as the adsorption and desorption of TEA molecules on the surface of the sensing materials. [ABSTRACT FROM AUTHOR]

The obscurity in selectivity mechanism has resulted in dilemmas in the research of selectivity properties of metal oxide semiconductor (MOS) gas sensing materials. In this work, selectivity mechanism of ZnO nanorod arrays to CH 3 OH is revealed by systematically simulating response and recovery reactions of three gas molecules (CH 3 OH, NH 3 and CO) based on density functional theory (DFT). Results suggest that selectivity to CH 3 OH is due to three factors: i. Response reaction of CH 3 OH on ZnO (1 0  1 -  0) is most exothermic, which is main reason for the selectivity against NH 3 . ii. Intermediates as well as products oxidized from CH 3 OH have strongest absorption ability, which hinders reabsorption of O 2 molecule, mainly leading to selectivity against CO. iii. H adatoms dissociated from CH 3 OH transfer most electrons to ZnO surface layers, which is also responsible for the selectivity. This work provides a new insight into selectivity mechanism and a practicable method to predict selectivity properties of MOSs. [ABSTRACT FROM AUTHOR]