Ultrasensitive room-temperature ethanol detection based on Au functionalized nanoporous SnO2/C60/SnO2 composites

Abstract

We have realized extremely sensitive, selective sub-ppm level ethanol gas detection through an Au functionalized nanoporous SnO₂/C₆₀/SnO₂ sensing composite. This new type of hierarchically nanoporous SnO₂ composite film supports both the Au@SnO₂/C₆₀ layer with closely packed open macropores (∼300 nm) and the bottom SnO₂ layer with highly ordered nanopores (8–10 nm). The structure, crystallinity and composition of the hierarchical structured Au@SnO₂/C₆₀/SnO₂ nanocomposite films are characterized by XRD, Raman, HRTEM, and SAED. The interaction between the Au/SnO₂ and C₆₀/SnO₂ heterojunctions in light of transfer of charge carriers and modulation of potential barriers plays a crucial role in enhancing the detecting performance. The sensing properties of the Au@SnO₂/C₆₀/SnO₂ nanocomposite sensor are investigated by exposing it to ethanol gas with a concentration range from 0.5 ppm to 50 ppm. Furthermore, the gas sensor exhibits ultrahigh sensitivity to ethanol gas with a response value of up to 16.8 at 0.5 ppm and a short recovery time of 9 seconds at room temperature.