Hydroxyls-induced oxygen activation on “inert” Au nanoparticles for low-temperature CO oxidation

The NaOH additive substantially enhances the catalytic activity of Au/SiO2 catalyst inert in catalyzing CO oxidation at temperatures below 150 °C, and Au/NaOH/SiO2 catalyst with a NaOH:Au atomic ratio of 6 is active at room temperature. Both the particle size distribution and the electronic structure of Au nanoparticles were found to be similar in Au/SiO2 and Au/NaOH/SiO2 catalysts, unambiguously proving that hydroxyls on “inert” Au nanoparticles can induce the activation of O2 for CO oxidation at room temperature. The accompanying density functional theory (DFT) calculation results reveal the determining role of COOH(a) in hydroxyls-induced activation of O2 on the Au(1 1 1) surface. Our results successfully elucidate the influence of hydroxyls on the intrinsic activity of Au nanoparticles in CO oxidation, providing novel insights into the role of hydroxyls in the catalytic activity of Au catalysts and advancing the fundamental understanding of oxidation reactions catalyzed by Au catalysts.

Graphical abstractHydroxyls can induce the activation of molecular oxygen on “inert” Au nanoparticles for low-temperature CO oxidation.Figure optionsDownload full-size imageDownload high-quality image (137 K)Download as PowerPoint slideResearch highlights► Hydroxyls on “inert” Au nanoparticles induce the activation of O2 to catalyze CO oxidation at room temperature. ► Chemisorbed COOH species plays the determining role in the hydroxyls-induced activation of O2 on the “inert” Au surface. ► Chemisorbed di-CO3H species on the Au surface is the poison in low-temperature CO oxidation. ► The accumulation of chemisorbed di-CO3H species on the Au surface is thermodynamically controlled.