Sponge-like loose and porous SnO2 microspheres with rich oxygen vacancies and their enhanced room-temperature gas-sensing performance

Structure and surface modification of semiconductor materials are of great importance in gas sensors. In this study, a facile citric acid-assisted solvothermal method via a precise calcination process was leveraged to synthesize sponge-like loose and porous SnO2 microspheres with rich oxygen vacancies (denoted as LP-SnO2-O-v). When this material was used in a gas sensor, it exhibited an extremely high response to 10 ppm hydrogen sulfide gas at room temperature (R-a/R-g = 9688), which was 54 times higher than that of commercial SnO2. Furthermore, the response time of LP-SnO2-O-v was 5 s, while the recovery time was 177 s. Moreover, it displayed such high selectivity and stability for hydrogen sulfide gas that its properties remained almost unchanged after 1 month. This method paves a new way to fabricate materials possessing a sponge-like loose and porous structure with oxygen vacancies, which is promising for many other scientific fields such as lithium-ion batteries and photocatalysis.

Automated summary

A facile citric acid-assisted solvothermal method was used to synthesize sponge-like loose and porous SnO2 microspheres with rich oxygen vacancies (LP-SnO2-O-v) for gas sensors. The LP-SnO2-O-v exhibited an extremely high response to hydrogen sulfide gas at room temperature, with a response rate 54 times higher than commercial SnO2. It also showed fast response and recovery times, as well as high selectivity and stability.