Probing Single Pt Atoms in Complex Intermetallic Al₁₃Fe₄

Abstract

The atomic structure of a 0.2 atom % Pt-doped complex metallic alloy, monoclinic AlFe, was investigated using a single crystal prepared by the Czochralski method. High-angle annular dark-field scanning transmission electron microscopy showed that the Pt atoms were dispersed as single atoms and substituted at Fe sites in AlFe. Single-crystal X-ray structural analysis revealed that the Pt atoms preferentially substitute at Fe(1). Unlike those that have been reported, Pt single atoms in the surface layers showed lower activity and selectivity than those of AlPt and bulk Pt for propyne hydrogenation, indicating that the active state of a given single-atom Pt site is strongly dominated by the bonding to surrounding Al atoms.

The Multifaceted Reactivity of Single‐Atom Heterogeneous Catalysts

“…[10] Aided by synthetic and analytical advancements,ahuge range of potential host materials has now been reported (Figure 2), which encompasses metal oxides, [11][12][13][14] metal hydroxides, [15,16] metals (also termed single-atom alloys (SAAs)), [17,18] micro/ mesoporous materials such as zeolites, [19,20] metal-organic frameworks (MOFs), [21,22] silicas, [23,24] carbon-based materials, [25][26][27][28] organopolymers, [29,30] nitrides, [31][32][33] and carbides. [10] Aided by synthetic and analytical advancements,ahuge range of potential host materials has now been reported (Figure 2), which encompasses metal oxides, [11][12][13][14] metal hydroxides, [15,16] metals (also termed single-atom alloys (SAAs)), [17,18] micro/ mesoporous materials such as zeolites, [19,20] metal-organic frameworks (MOFs), [21,22] silicas, [23,24] carbon-based materials, [25][26][27]…”

“…One of the first challenges in the development of SACs was how to stabilize metal atoms against sintering or leaching in sufficient amounts to give appreciable activity.M etalcontaining zeolites and zeotypes,inwhich metal centers were mainly isolated in crystallographic positions,were among the most notable early examples of successful SACs. [10] Aided by synthetic and analytical advancements,ahuge range of potential host materials has now been reported ( Figure 2), which encompasses metal oxides, [11][12][13][14] metal hydroxides, [15,16] metals (also termed single-atom alloys (SAAs)), [17,18] micro/ mesoporous materials such as zeolites, [19,20] metal-organic frameworks (MOFs), [21,22] silicas, [23,24] carbon-based materials, [25][26][27][28] organopolymers, [29,30] nitrides, [31][32][33] and carbides. [34] Further extending the diversity of this framework with host functionalization strategies (such as,t hrough partial surface hydration, [35] introduction of alkali metals, [36] or decoration with ethylene glycolate species [37] )h as also been demonstrated to successfully enhance the anchoring of metal atoms.…”

Catalytic activation of a non-noble intermetallic surface through nanostructuration under hydrogenation conditions revealed by atomistic thermodynamics

“…This leads to unique coordination geometries [8][9][10] , and to isolated active sites. The latter especially holds in the case of complex intermetallic compounds, a class of ordered alloys comprising quasicrystals, their approximants and other ordered compounds with large unit cells 11,12 .…”

Catalytic properties of Al13TM4complex intermetallics: influence of the transition metal and the surface orientation on butadiene hydrogenation

“…The surfaces of these materials can expose Al pentagons centered by the TMs, which are believed to be the catalytically active centers [31]. Besides, Al 13 Fe 4 has been recently proposed as a template for substituting single Pt atoms at Fe sites [32].…”