fig5

Figure 5. Enhanced CO sensing performance of atomically dispersed Pd on TiO₂ and underlying mechanistic insights. (A) Response-recovery curves of Pd₁-TiO₂ toward CO at concentrations from 0.1 to 100 ppm; (B) Comparison of CO (100 ppm) responses for TiO₂, Pd nanoparticles-loaded TiO₂ (Pd NPs-TiO₂), and Pd₁-TiO₂ sensors; (C) Linear correlation between response and CO concentration for TiO₂, Pd NPs-TiO₂, and Pd₁-TiO₂; (D) Response and recovery time of different TiO₂-based sensors toward 100 ppm CO; (E) Selectivity of Pd₁-TiO₂ toward CO against various interference gases; (F) Proposed CO sensing mechanism highlighting the Pd-O-Ti interfacial active sites; (G) Relative ratios of surface oxygen species derived from O 1s X-ray photoelectron spectroscopy spectra; (H) In situ diffuse reflectance infrared Fourier transform spectroscopy of different sensors; (I) Density functional theory-calculated adsorption energies of various gases on Pd₁-TiO₂. Reproduced with permission from Ref.^[9]. Copyright 2021, American Chemical Society. LOD: Limit of detection; CV: coefficientof variation; NP: nanoparticle; KM: Kubelka-Munk.