Shahar Dery - Video Lecture

Shahar Dery - Video Lecture

IVS-IPSTA 2020 Online Conference December 13, 2020

Energy and Catalysis Session
Session chair:
Malachi Noked

Bar-Ilan University

 

Intra-Particle Hydrogen Spillover from the Oxide-Metal Interface Triggers Site-Independent Hydrogenation Reactions within Single Particles

Shahar Dery

Institute of Chemistry, The Hebrew University of Jerusalem


Abstract


Metal-support interactions in heterogeneous catalysts have been widely utilized for optimizing the catalytic reactivity of oxide-supported metallic nanoparticles. In various examples these catalysts were characterized with high and localized reactivity at the oxide-metal interface. However, catalytically-active sites are not necessarily restricted to the oxide-metal interface but reside as well on the metal surface. Uncovering the interconnection between reactive sites that are located at the oxide-metal interface and those that are located at the metal surface is of crucial importance for understanding the reaction mechanism of catalytic nanoparticles. Herein, we use high spatial resolution IR nanospectroscopy to map the localized reactivity in hydrogenation reactions on single oxide-supported Au and Pt particles while using nitrofunctionalized ligands as probes molecules. The experimental results specified that for oxidesupported Au particles the hydrogenation reaction was initiated by hydrogen dissociation at the oxide-metal interface. This step was followed by efficient intra-particle hydrogen spillover from the oxide-metal interface to the interior parts of the particle that led to uniform reactivity across the particles’ surface. In contrast, the oxide-metal interface had only minor influence on the reactivity of Pt particles, in which the hydrogenation reaction was dominated by highly reactive metal sites. Single particle measurements therefore revealed that long-range (>100 nm) effects of metal/oxide boundaries dominate the reactivity of oxide-supported Au particles in hydrogenation reactions. These long-range effects can be exploited to improve the performance of catalysts for reactions in which spillover from the metal/support surface is essential.