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Controlled Synthesis of Carbon-Supported Gold Clusters for Rational Catalyst Design
Controlled Synthesis of Carbon-Supported Gold Clusters for Rational Catalyst Design
- Source :
- Chemical record (New York, N.Y.). 16(5)
- Publication Year :
- 2016
-
Abstract
- The development of novel catalysts based on metal clusters requires a rational design principle as well as atomically precise synthetic methods. Toward this goal, we have developed a method to precisely and independently control the size, composition, and surface modification of heterogeneous gold clusters by calcination of the ligand-protected Au clusters on carbon supports. We studied the effects of these structural parameters using benzyl alcohol oxidation as a test reaction. Unexpectedly, Au144 and Au∼330 on hierarchically porous carbon exhibited significantly higher turnover frequency than Au25 and Au38. This size dependence is ascribed to the difference in the geometric structures of the Au clusters; Au144 and Au∼330 have an icosahedral-based structure whereas Au25 and Au38 have a face-centered cubic structure. Doping of a single Pd atom into Au25 supported on carbon nanotubes remarkably enhanced the catalytic activity. The doping effect is explained in terms of the accelerated formation of the carbocation intermediate due to electron transfer from Pd to Au, since the doped Pd is buried within the Au clusters and is located at the interface between the supports. Residual thiolates on Au25 affected both the activity and selectivity; selective oxidation to benzaldehyde was achieved at optimized coverage. Non-formation of benzoic acid is due to the suppression of oxidation activity by electron withdrawal by thiolates and non-formation of benzyl benzoate is due to the site-isolation effect by thiolates. These results will provide useful information for the rational design of gold-cluster-based catalysts with desired performance.
- Subjects :
- Chemistry
General Chemical Engineering
chemistry.chemical_element
02 engineering and technology
General Chemistry
Carbon nanotube
010402 general chemistry
021001 nanoscience & nanotechnology
Photochemistry
01 natural sciences
Biochemistry
0104 chemical sciences
Catalysis
law.invention
Electron transfer
chemistry.chemical_compound
law
Benzyl alcohol
Materials Chemistry
Organic chemistry
Calcination
0210 nano-technology
Selectivity
Carbon
Benzoic acid
Subjects
Details
- ISSN :
- 15280691
- Volume :
- 16
- Issue :
- 5
- Database :
- OpenAIRE
- Journal :
- Chemical record (New York, N.Y.)
- Accession number :
- edsair.doi.dedup.....efe16ed64a27c0cccca920a7fb723adb