Hierarchically porous Au-ZnO/ZIF-8 heterostructure fabricated via interface oxidation for highly sensitive and selective triethylamine sensing in ppb-level

Triethylamine is an organic amine compound with strong irritancy and toxicity that threatens ecological balance and human health, making accurate detection crucial. However, achieving high sensitivity and selective detection of TEA in ppb level is challenging. Herein, we have successfully prepared an Au-ZnO/ZIF-8 via an interface oxidation strategy followed by Au nanoparticles loading. The synthesis process involves three key steps: firstly, ZnO nanofibers are prepared by electrospinning, followed by in-situ coordination growth to form a ZIF-8 layer on the ZnO surface; subsequently, Au nanoparticles are decorated onto the ZnO/ZIF-8 surface through an impregnation-reduction method; finally, the composites are calcined in a tube furnace to generate oxidation layers while retaining the intrinsic properties of ZIF-8. Sensing tests toward 100 ppm TEA reveal that the Au-ZnO/ZIF-8 sensor exhibits a response of 1012.5 with a low detection limit of 2.78 ppb at 235 °C. This performance is 13.9-fold higher than that of ZnO/ZIF-8 (72.9 at 303 °C) and 30.5-fold higher than that of pristine ZnO (33.1 at 328 °C). Furthermore, the sensor demonstrates high selectivity for TEA, short response times (7 s), as well as excellent repeatability and stability. It indicates that the Au-ZnO/ZIF-8 sensor holds great potential for practical TEA detection, thereby providing a feasible strategy to improve the gas detection capabilities of MOF-based sensors.