Enhancing the surface activity of perovskite oxide acetone gas sensors with functionalized heterojunctions

Abstract

Perovskite oxide scaffolds have attracted attention in the field of gas sensors, perovskite oxides are a class of promising candidates since they operate at relatively low voltage and possess thermal and structural stability. However, the oxides suffer from critical issues such as low surface area and limited surface activity, which arise from high-temperature synthesis and make some limitations of sensing characteristics. To overcome these challenges, we propose a synthetic route to construct numerous heterointerfaces at the oxide nanofibers. We modulated the hole accumulation layer of p-type $La_{0.8}Ca_{0.2}Fe_{0.98}Pt_{0.02}O_3$ nanofibers by binding Pt-dispersed n-type α-$Fe_2O_3$ onto the surface-active sites. Metal-organic framework-mediated α-$Fe_2O_3$ encapsulates Pt species, which we expect to maximize the catalytic activity as a chemical sensitizer. Such nano-sized heterostructures heightened the surface activity of the perovskite oxides, thereby achieving top-ranked acetone sensing characteristics compared to perovskite-type sensing layers ($R_g/R_a$ = 39.8 toward 10 ppm acetone at 250°C). In this work, the synthetic route of perovskite oxide with highly enhanced surface activity would give insight into various catalysis applications.