On the Reactivity of Carbon Supported Pd Nanoparticles during NO Reduction: Unraveling a Metal–Support Redox Interaction

Abstract

Pd nanoparticles (NPs) were successfully obtained by the reduction of PdCl₂ with l-ascorbic acid, whose morphology was revealed by HRTEM to be a worm-like system, formed by linked crystallite clusters with an average short-axis diameter of 5.42 nm. In situ UV–vis absorption measurements were used to monitor their formation, while XPS and XRD characterization confirmed the NPs’ metallic state. A straightforward way to support the obtained Pd NPs on activated carbon (AC) was used to prepare a catalyst for NO decomposition reaction. The Pd/AC catalysts proved to be highly active in the temperature range of 323 to 673 K, and a redox mechanism is proposed, where the catalyst’s active sites are oxidized by NO and reduced by carbon, emitting CO₂ and enhancing their capacity to absorb and dissociate NO