Pt/GO/TiO₂ room–temperature hydrogen sensing Schottky diode: High resistance to humidity interference endowed by the graphene oxide interlayer

Room–temperature hydrogen sensors usually suffer from dramatic response drop in humid air. Aiming to solve such issue of H₂ sensing Schottky diodes, a platinum/graphene oxide/titanium dioxide (Pt/GO/TiO₂) Schottky diode is designed. The GO interlayer between the 50–nm–thick Pt nanolayer and TiO₂ substrate significantly improves resistance to humidity interference. Remarkably, the diode with a GO loading of 0.969 mg cm⁻² exhibits a response retention rate (R_RH95%/R_dry) of nearly 100%. To reveal the mechanism for the improved anti–humidity performance, the H₂O adsorption behavior of Pt/GO/TiO₂ diode was investigated by quartz crystal microbalance and near ambient pressure X–ray photoelectron spectroscopy. H₂O molecules are absent on the Pt surface of Pt/GO/TiO₂ in water vapor. This is a result of the H₂O adsorption effect of the GO interlayer, which stems from the superior H₂O adsorption ability of the GO interlayer and causes the diffusion of H₂O molecules adsorbed on the Pt surface into the GO interlayer through nanochannels in the Pt nanolayer. Additionally, the GO interlayer serves as a blocking layer for the diffusion of hydroxyl species generated on the TiO₂ surface to the Pt nanolayer. Such hydroxyl blocking effect prevents the consumption of adsorbed H atoms at the Pt/GO interface.