Effect of Interface between Oxides and Noble Metal on Gas-Sensing Reactions

Abstract

Loading noble metals is an effective way of enhancing the gas-sensing performance of metal oxide semiconductor (MOS) materials. Although the catalytic sites of noble metals can promote the sensing reaction of gas molecules, the mechanism of how noble metals influence the MOS resistance remains unclear. Herein, SnO₂ was combined with Pd metallene to construct a nanocomposite as a model material for investigating the gas-sensing mechanism at the interface between oxides and noble metals. Due to the large lateral scale, unique electron transfer capabilities and excellent catalytic properties, Pd metallene was used as a substitute for noble metal particles. Characterization and theoretical analysis revealed the strong metal–support interactions (SMSI) between Pd metallene and SnO₂. Density functional theory (DFT) calculations and experimental results indicated that Pd metallene exhibits high adsorption and electron transfer capabilities for the ethanol molecule. SMSI played a crucial role in the electron transfer at the Pd metallene–SnO₂ interface during the gas-sensing reaction, thereby promoting changes in the resistance of SnO₂. This work demonstrates the potential of Pd metallene and provides new insights into the gas-sensing reaction of MOS loaded with noble metals.