Enhanced acetone gas sensing performance of ZnO polyhedrons decorated with LaFeO₃ nanoparticles

Since acetone is potentially harmful to humans, it is necessary to develop a high-performance acetone gas sensor. In this study, ZnO polyhedrons decorated with LaFeO3 (LFO) nanoparticles with high acetone-sensing performances were prepared by a facile microwave-assisted hydrolytic reaction method, and the p-n heterojunction was successfully constructed. The crystal structure, surface morphology, and internal composition of the LaFeO3/ZnO composites were analyzed by various characterization methods. The results showed that LaFeO3 nanoparticles were successfully composited with ZnO polyhedra. Compared with the pure ZnO sensor, the LaFeO3/ZnO sensor showed a significant improvement in sensitivity, recovery time, and selectivity. For example, at the optimal operating temperature of 340 degrees C, the response of the LaFeO3/ZnO sensor to 100 ppm acetone could reach similar to 208.7, which was 39 times higher than that of the pure ZnO sensor. And the recovery time of the LaFeO3/ZnO sensor was reduced to 15.4 s. Meanwhile, the LaFeO3/ZnO sensor had the highest selectivity for acetone. The significant improvement of the sensing performance of the LaFeO3/ZnO sensor might be attributed to the formation of p-n heterojunctions and the good catalytic effect of LaFeO3.