ZnO/ZnFe2O4 heterostructure for conductometric acetone gas sensors

Heterojunction interfaces between two metal-oxides can provide significant advantages in gas sensing through charge distribution caused by lattice mismatch. Herein, we report the positive synergistic effects that enhance the sensing properties of ZnO/ZnFe2O4. Pure ZnO, ZnFe2O4 and ZnO/ZnFe2O4 heterostructures derived from a hydrothermal method were used to fabricate gas detecting sensing layers. The sensing behavior of the fabricated sensing layers was investigated to evaluate the effects of lattice mismatch created by heterojunction between the ZnO and ZnFe2O4 nanoparticles. Compared with pure ZnO and ZnFe2O4, ZnO/ZnFe2O4 heterostructure at a molar ratio of 1:3 exhibited the best sensing performance, with a response of 92.9 towards 90 ppm acetone, response-recovery times of only 7.7 s/27 s, and lower detection limit of 0.18 ppm. Such significant improvements were due to higher concentration of oxygen vacancies at the interface of ZnO/ZnFe2O4 and enhanced catalytic activity.

Automated summary

Heterojunction interfaces between metal-oxides can significantly improve gas sensing through charge distribution caused by lattice mismatch. This study focuses on the positive synergistic effects of ZnO/ZnFe2O4 heterostructure, which exhibited the best sensing performance among pure ZnO and ZnFe2O4. The enhanced sensing properties were attributed to the higher concentration of oxygen vacancies at the ZnO/ZnFe2O4 interface and enhanced catalytic activity.