Hydrogen Spillover in Encapsulated Metal Catalysts: New Opportunities for Designing Advanced Hydroprocessing Catalysts

Abstract

Hydrogen spillover has been one of the most debated concepts in the field of heterogeneous catalysis due to limited ways of studying it. The main controversies in hydrogen spillover, especially from the viewpoint of its catalytic functions, can be mainly attributed to the absence of well‐defined model catalysts that can provide direct proof of the catalytic functions of hydrogen spillover. In this article, we will provide an overview of the recent progress made with encapsulated metal catalysts, which can act as an ideal model catalyst for proving the existence and catalytic functions of hydrogen spillover. We will also demonstrate unique opportunities of using the encapsulated metal catalysts for designing advanced hydroprocessing catalysts with enhanced activity, distinct chemoselectivity, and increased catalyst durability.

Activation and Spillover of Hydrogen on Sub‐1 nm Palladium Nanoclusters Confined within Sodalite Zeolite for the Semi‐Hydrogenation of Alkynes

“…Subsequently, surface hydroxyl groups can be formed through hydrogen spillover processes. A similar reaction mechanism of hydrogen spillover and hydroxyl formation has also been observed over Pt@zeolite encapsulated catalysts …”

Generation of subnanometric platinum with high stability during transformation of a 2D zeolite into 3D

“…10,11 This method has been used, so far, for the synthesis of Al-containing zeolites and the metal nanoparticles encapsulated in those zeolites are resistant to sintering. 12 Nevertheless, in some cases, the introduction of Al into the zeolites may restrict the reaction scope of these materials because of the acidity associated to the presence of Al sites. Gates et al have prepared single metal atoms and metal clusters (below 1 nm) confined in zeolites and performed excellent detailed characterizations on the location and atomic structure of these metal species.…”

Activation and Spillover of Hydrogen on Sub‐1 nm Palladium Nanoclusters Confined within Sodalite Zeolite for the Semi‐Hydrogenation of Alkynes

“…[29] Subsequently,surface hydroxyl groups can be formed through hydrogen spillover processes.Asimilar reaction mechanism of hydrogen spillover and hydroxyl formation has also been observed over Pt@zeolite encapsulated catalysts. [35][36][37] Ther eactivity of OH species on the SOD surface was further studied by in situ DRIFTS isotopic experiments (Figure 3). Thes amples were first reduced in aH 2 atmosphere,a nd then the evolution of the surface species was monitored.…”