Galvanic replacement reaction in perovskite oxide for superior chemiresistors

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 1; no. 43; pp. 23282 - 23293
• Main Authors: Baek, Jong Won, Kim, Yoon Hwa, Ahn, Jaewan, Kim, Dong-Ha, Shin, Hamin, Ko, Jaehyun, Park, Seyeon, Park, Chungseong, Shin, Euichul, Jang, Ji-Soo, Kim, Il-Doo
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 08.11.2022
• Subjects: Acetylene; Air monitoring; Air pollution; Chemical perception; Chemoreception; Ferrites; Gas sensors; Lanthanum compounds; Nanotechnology; Nanotubes; P-n junctions; Perovskites; Pollution detection; Pollution levels; Pollution monitoring; Reaction time; Selectivity; Tin dioxide
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d2ta05338a

It is well known that certain gas molecules can serve as specific markers for characterizing the physiological and environmental nature of a subject, such as acetylene gas which can be used for determining a person's smoking status as well as for monitoring air pollution levels. For their reliable detection, gas sensors should be designed with high sensing capabilities in terms of selectivity, sensitivity and low detection limit. In this work, we present a rational design approach for the synthesis of p-type LaFeO 3 /n-type SnO 2 composite nanotubes (NTs) via galvanic replacement reaction (GRR) on electrospun perovskite LaFeO 3 NTs for p-n type-converted sensing. The GRR process provides LaFeO 3 /SnO 2 NTs with high surface area (146.6 m 2 g −1 ) by generating SnO 2 nanograins (<10 nm), as controlled by varying the reaction time. The abundant heterogeneous p-n junctions formed in LaFeO 3 /SnO 2 NTs contribute to the dramatic improvements in their sensing characteristics. In fact, the LaFeO 3 /SnO 2 NTs exhibited 31.2-fold increased response toward acetylene (5 ppm) with a far improved response speed (16 s) compared to that of pristine LaFeO 3 NTs (64 s). Our results demonstrate that the GRR process can be used to engineer the morphology and composition of p-type perovskites to achieve exceptional chemical sensing performances. This work presents the synthesis of LaFeO 3 /SnO 2 nanotubes (NTs) based on the GRR process, with perovskite LaFeO 3 NTs prepared by electrospun nanofibers as the starting material resulting in a significantly enhanced catalytic activity.