Novel strategy to construct porous Sn-doped ZnO/ZnFe2O4 heterostructures for superior triethylamine detection

The reasonable design of heterostructure is of great significance to the development of high-performance gas sensors for practical applications. Herein, a series of Sn-doped ZnO/ZnFe2O4 (Sn-ZZFO) porous heterostructures were firstly synthesized by doping a certain amount (n wt%) of Sn4+ (n = 1.08, 2.47, and 3.75 for Sn-ZZFO-1–3, respectively) into the Prussian blue analogue (PBA)-derived ZnO/ZnFe2O4 (ZZFO) heterostructure. As a result, the Sn-ZZFO-2 exhibited excellent triethylamine (TEA) sensing performances at 270 °C. Its response value to 10 ppm triethylamine was 28.1, which was ca. 8.0, 4.2 and 4.8 times higher than those of ZZFO, (280 °C), Sn-ZZFO-1 and Sn-ZZFO-3, respectively, and even superior to the most of the ZnO-based, SnO2-based, ZnFe2O4-based and reported ZnO/ZnFe2O4 sensor materials. Moreover, Sn-ZZFO-2 possessed low detection limit (<0.2 ppm), excellent selectivity, and short response and recovery times (9 and 7 s) to TEA. The optimized gas sensing performances to TEA were ascribed to the doping a suitable amount Sn4+ into the ZZFO heterostructure, and the unique Sn-ZZFO-2 multistage pore nanosphere structure. This work highlights an efficient method for preparing porous metal ion doped heterostructures for efficient gas detection.