Enhanced visible light-excited ZnSnO3 for room temperature ppm-level CO2 detection

Abstract

• ZnSnO 3 was synthesized by a one-step facile hydrothermal method. • ZnSnO 3 coatings exhibited excellent responses to CO 2 at room temperature. • ZnSnO 3 based sensors showed good repeatability and long-term stability. • Enhancing mechanism of sensing properties was attributed to oxygen vacancies. Aimed at the bottleneck problem in conventional gas sensors that the effective detection of CO 2 gas can only be accomplished at concentrations above thousands of ppm and higher operating temperature, in this work, microstructured ZnSnO 3 equipped with rambutan-like hexahedral features with the hollow interior was successfully synthesized through a facile one-step hydrothermal method. Visible light was utilized as an excitation source to further enhance the sensing property. The investigation elaborated that at optimum hydrothermal time of 16 h, ZnSnO 3 showed a high gas response (~4.65), repeatability, and long-term stability towards 400 ppm CO 2 at room temperature. The response under purple light was 3.5 times higher than that under dark conditions, resulting from photoelectrons' generation. Furthermore, ZnSnO 3 sensor had excellent selectivity to 50 ppm CO 2 . The large specific surface area and abundant oxygen vacancies of ZnSnO 3 contribute to the excellent gas-sensing performance, which addresses the dilemma that it is difficult to break through the energy barrier through surface interaction to impact the band structure and carrier concentration because CO 2 is a non-polar molecule formed by polar bonds. Therefore, ZnSnO 3 is a promising material for the development of devices utilized in medical respiratory detection, agricultural crop growth detection and other fields.