Evolution of Isolated Atoms and Clusters in Catalysis

Liu, Lichen; Corma, Avelino

doi:10.1016/j.trechm.2020.02.003

Cited by 163 publications

(142 citation statements)

References 109 publications

(124 reference statements)

Supporting

Mentioning

134

Contrasting

Order By: Relevance

“…In this case, the reaction rate decrease is relatively mild for mcNAs and scNAs. Ideally, a partially or totally bare catalyst, respectively mcNAs and scNAs, tends to expose the maximum number of active sites on the catalyst surface [47]. Thus, the two opposite effects are buffered and both the mcNAs and scNAs still maintain some catalytic features.…”

Section: Formic Acid Catalytic Decompositionmentioning

confidence: 99%

Total- and semi-bare noble metal nanoparticles@silica core@shell catalysts for hydrogen generation by formic acid decomposition

et al. 2021

View full text Add to dashboard Cite

Catalysts are involved in a number of established and emerging chemical processes as well as in environmental remediation and energy conversion. Nanoparticles (NPs) can offer several advantages over some conventional catalysts, such as higher efficiency and selectivity. Nowadays, versatile and scalable nanocatalysts that combine activity and stability are still lacking. Here, we report a comprehensive investigation on the production and characterization of hybrid nano-architectures bringing a partial or total bare surface together with their catalytic efficiency evaluation on, as a proof-of-concept, the formic acid decomposition reaction. In this regard, formic acid (FA) is a convenient and safe hydrogen carrier with appealing features for mobile applications, fuel cells technologies, petrochemical processes and energetic applications. Thus, the design of robust catalysts for FA dehydrogenation is strongly demanded. Due to this, we produced and evaluated nano-architectures with various equilibrium between the size-increase of the active part and the barer catalytic surface. Overall, this work paves the way for the development of new approaches for green energy storage and safe delivery.

show abstract

Section: Formic Acid Catalytic Decompositionmentioning

confidence: 99%

Total- and semi-bare noble metal nanoparticles@silica core@shell catalysts for hydrogen generation by formic acid decomposition

et al. 2021

View full text Add to dashboard Cite

show abstract

“…As a result, ingenious control of nucleation conditions can create various nanomaterials with prominent size and geometry‐dependent functionality. [ 10–16 ] However, it is still a great challenge to isolate ultrafine NCs in liquid phase because the crystal nuclei are extremely prone to aggregation without the stabilizers in the initial nucleation process.…”

Section: Introductionmentioning

confidence: 99%

Unveiling Single Atom Nucleation for Isolating Ultrafine fcc Ru Nanoclusters with Outstanding Dehydrogenation Activity

Wang

Shi

et al. 2020

Advanced Energy Materials

View full text Add to dashboard Cite

Unveiling the nucleation process for controlling aggregation of metal cations into structure-specific crystal nuclei represents a key step for isolating ultrafine nanoclusters (NCs) with advanced functionality. [1-6] In liquid phase, metal cation nucleation into ultrafine crystal nuclei represents an essential step in the crystallization of nanomaterials. These ultrafine clusters have been regarded as key intermediates during self-catalyzed crystal growth, [7-9] which have played a decisive role in the precise control of the size and structure of the final products. As a result, ingenious control of nucleation conditions can create various nanomaterials with prominent size and geometry-dependent functionality. [10-16] However, it is still a great challenge to isolate ultrafine NCs in liquid phase because the crystal nuclei are extremely prone to aggregation without the stabilizers in the initial nucleation process. Ru metal tends to adopt hexagonal close packed (hcp) structures with low potential energy in the bulk phase at all temperature ranges. [17-19] Recently, more attention has been paid to explore Ru nanoparticles (NPs) in face-centered cubic (fcc) phase with more exposed active sites than their hcp analogue. [20] They usually exhibit much higher catalytic activity than that of hcp Ru NPs in a number of reactions, such as methanol oxidation, hydrogenation, Fischer-Tropsch synthesis, and dehydrogenation, especially for ammonia borane (AB) methanolysis. [21-30] Recently, controlled synthesis of ultrafine fcc Ru NCs has been of significant interest to further greatly improve their catalytic efficiency. [28,29] Up to date, fcc Ru NPs with sizes > 2.0 nm have been confirmed by theoretical and experimental investigations. For example, fcc Pt NPs were applied as core for epitaxial growth to form 6.8 ± 1.5 nm fcc Ru NPs with polyvinylpyrrolidone as a weak stabilizer. [27] In another case, pure fcc Ru NPs with a diameter of 2−5.5 nm were synthesized via a chemical reduction method with γ-Al 2 O 3 as the support. [28] Most recently, Zhou and co-workers designed a negatively charged porous coordination cages as a template for the synthesis of ultrafine fcc Ru NCs with an average size of 2.5 nm. This particular work exhibits a record high turnover frequency (TOF) of 304.4 min −1 in AB methanolysis. [29] These small fcc Ru NPs are all confirmed as high-performance catalysts due to the exposure of high energy crystal plane. They were all obtained Ultrafine face-centered cubic (fcc) ruthenium nanoclusters (NCs) are of great interest due to their super high catalytic activity. However, it is extremely difficult to prepare ≈1 nm fcc ruthenium NCs with high energy atoms due to their easy aggregation. Herein, the nucleation process of ruthenium centers by confined pyrolysis of a multivariate metal-organic framework to isolate ultrafine fcc NCs (from single atom to 1.33 nm) via in situ formed stabilizers is unveiled. Systematic investigations demonstrate that preferential nucleation of Ru single atoms to fcc clusters in the i...

show abstract

“…In this framework, spectroscopic characterization of catalysts under reaction conditions is an important research field [1], where new and improved technologies with better temporal and spatial resolutions continuously emerging, enabling more accurate identification of active species and reaction intermediates [2]. The dynamic nature of catalysts, which tend to adapt to the reaction environment-experiencing remarkable morphological and compositional and modifications affecting their catalytic activity-cannot be ignored [3,4]. The combination of multiple spectroscopic tools for studying catalysts under 'in situ' (i.e., operando) or near to real conditions is essential 2 of 15 for a comprehensive picture of the active sites under steady state or transient conditions [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Influence of the ZrO2 Crystalline Phases on the Nature of Active Sites in PdCu/ZrO2 Catalysts for the Methanol Steam Reforming Reaction—An In Situ Spectroscopic Study

et al. 2020

View full text Add to dashboard Cite

In this work, the electronic properties of the metal sites in cubic and monoclinic ZrO2 supported Pd and PdCu catalysts have been investigated using CO as probe molecule in in-situ IR studies, and the surface composition of the outermost layers has been studied by APXPS (Ambient Pressure X-ray Photoemission Spectroscopy). The reaction products were followed by mass spectrometry, making it possible to relate the chemical properties of the catalysts under reaction conditions with their selectivity. Combining these techniques, it has been shown that the structure of the support (monoclinic or cubic ZrO2) affects the metal dispersion, mobility, and reorganization of metal sites under methanol steam reforming (MSR) conditions, influencing the oxidation state of surface metal species, with important consequences in the catalytic activity. Correlating the mass spectra of the reaction products with these spectroscopic studies, it was possible to conclude that electropositive metal species play an imperative role for high CO2 and H2 selectivity in the MSR reaction (less CO formation).

show abstract

Evolution of Isolated Atoms and Clusters in Catalysis

Cited by 163 publications

References 109 publications

Total- and semi-bare noble metal nanoparticles@silica core@shell catalysts for hydrogen generation by formic acid decomposition

Total- and semi-bare noble metal nanoparticles@silica core@shell catalysts for hydrogen generation by formic acid decomposition

Unveiling Single Atom Nucleation for Isolating Ultrafine fcc Ru Nanoclusters with Outstanding Dehydrogenation Activity

Influence of the ZrO2 Crystalline Phases on the Nature of Active Sites in PdCu/ZrO2 Catalysts for the Methanol Steam Reforming Reaction—An In Situ Spectroscopic Study

Contact Info

Product

Resources

About