Title:
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Stabilization of Single Metal Atoms on Graphitic Carbon Nitride
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Author:
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Chen, Zupeng; Mitchell, Sharon; Vorobyeva, Evgeniya; Leary, Rowan K.; Hauert, Roland; Furnival, Tom; Ramasse, Quentin M.; Thomas, John M.; Midgley, Paul A.; Dontsova, Dariya; Antonietti, Markus; Pogodin, Sergey; López, Núria; Pérez-Ramírez, Javier
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Abstract:
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Graphitic carbon nitride (g-C3N4) exhibits unique properties as a support
for single-atom heterogeneous catalysts (SAHCs). Understanding how the
synthesis method, carrier properties, and metal identity impact the isolation of
metal centers is essential to guide their design. This study compares the effectiveness
of direct and postsynthetic routes to prepare SAHCs by incorporating
palladium, silver, iridium, platinum, or gold in g-C3N4 of distinct morphology
(bulk, mesoporous and exfoliated). The speciation (single atoms, dimers,
clusters, or nanoparticles), distribution, and oxidation state of the supported
metals are characterized by multiple techniques including extensive use of
aberration-corrected electron microscopy. SAHCs are most readily attained via
direct approaches applying copolymerizable metal precursors and employing
high surface area carriers. In contrast, although post-synthetic routes enable
improved control over the metal loading, nanoparticle formation is more prevalent.
Comparison of the carrier morphologies also points toward the involvement
of defects in stabilizing single atoms. The distinct metal dispersions are
rationalized by density functional theory and kinetic Monte Carlo simulations,
highlighting the interplay between the adsorption energetics and diffusion
kinetics. Evaluation in the continuous three-phase semihydrogenation of
1-hexyne identifies controlling the metal–carrier interaction and exposing the
metal sites at the surface layer as key challenges in designing efficient SAHCs. |
Publication date:
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2017-01-13 |
Subject(s):
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54 |
Rights:
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L'accés als continguts d'aquest document queda condicionat a l'acceptació de les condicions d'ús establertes per la següent llicència Creative Commons:http://creativecommons.org/licenses/by-nc-nd/4.0/ |
Pages:
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05785 p. |
Document type:
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Article Article - Accepted version |
DOI:
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10.1002/adfm.201605785
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