Ordered Mesoporous Tin Oxide Semiconductors with Large Pores and Crystallized Walls for High-Performance Gas Sensing

Owing to their distinct chemical and physical properties, mesoporous metal oxide semiconductors have shown great application potential in catalysis, electrochemistry, energy conversion, and energy storage. In this study, mesoporous crystalline SnO₂ materials have been synthesized through an evaporation-induced co-assembly (EICA) method using poly(ethylene oxide)-b-polystyrene diblock copolymers as the template, tin chlorides as the tin sources, and tetrahydrofuran as the solvent. By controlling conditions of the co-assembly process and employing a carbon-supported thermal treatment strategy, highly ordered mesoporous SnO₂ materials with a hexagonal mesostructure (space group P6₃/mmc) and crystalline pore walls can be obtained. The mesoporous SnO₂ is employed for fabricating gas sensor nanodevices which exhibit an excellent sensing performance toward H₂S with high sensitivity (170, 50 ppm) and superior stability, owing to its high surface area (98 m²/g), well-connected mesopores of ca. 18.0 nm, and high density of active sites in the crystalline pore walls. The chemical mechanism study reveals that both SO₂ and SnS₂ are generated during the gas sensing process on the SnO₂-based sensors.