Fast and real-time acetone gas sensor using hybrid ZnFe2O4/ZnO hollow spheres

Special hollow ZnFe2O4/ZnO hybrid spheres were successfully designed and synthesized via a facile hydrothermal procedure. Carbon spheres were used as the core template, which were removed during the calcination process in an air-rich atmosphere, thus leading to interior voids and an outer shell structure due to the contraction and combustion of the carbon spheres. The hybrid ZnFe2O4/ZnO hollow spheres not only possess a hollow structure, but also have a porous shell with a thickness of approximately 30 nm. Inspired by this special structure and design composition, a gas sensor based on the hybrid ZnFe2O4/ZnO hollow spheres showed a high response and fast response/recovery speed compared with nanoparticles. A short response time usually enables a gas sensor to accurately detect and real-time monitor a certain target gas. This study may give insight for the rational fabrication of high performance sensing materials.