LaFeO3/Co3O4 nanofibers with p-p heterojunction for enhanced formaldehyde sensing performance at low temperature

Perovskite semiconductors have been developed rapidly in the field of gas sensors because of their unique structure. In this paper, LaFeO₃/Co₃O₄ composite nanofibers were prepared by uniaxial electrospinning combined with annealing. The results demonstrate that the LaFeO₃/Co₃O₄ composite exhibits a uniform nanofiber structure with a diameter of about 180 nm and a rough and porous surface. The gas-sensing test data that contrasted with pure LaFeO₃, the response value of LaFeO₃/Co₃O₄ nanofibers to formaldehyde gas was markedly improved (from 12.65 to 27.82), and the operating temperature was also reduced (100 ℃). In addition, it has excellent response-recovery time and stability. Through mechanism analysis and density functional theory (DFT) studies, the improved performance of the LaFeO₃/Co₃O₄ sensor is attributed to the porous fiber structure, high specific surface area, abundant oxygen vacancy and p-p heterojunction. In addition, the high catalytic activity of Co₃O₄ promotes surface chemical reactions, accelerates electron transfer, and greatly improves gas-sensing performance. This paper offers an excellent strategy for the design of high-performance LaFeO₃-based formaldehyde sensors.