Insights into the dominant factors of porous gold for CO oxidation

Journal Article · Thu Jan 21 00:00:00 EST 2016 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4940307· OSTI ID:22493672

Kameoka, Satoshi; Miyamoto, Kanji ^[1]; Tanabe, Toyokazu ^[2]; Tsai, An Pang ^[1]

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1. Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)
2. Kanagawa University, Yokohama 221-8686 (Japan)

Three different porous Au catalysts that exhibit high catalytic activity for CO oxidation were prepared by the leaching of Al from an intermetallic compound, Al{sub 2}Au, with 10 wt. %-NaOH, HNO{sub 3}, or HCl aqueous solutions. The catalysts were investigated using Brunauer-Emmett-Teller measurements, synchrotron X-ray powder diffraction, hard X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy (TEM). Broad diffraction peaks generated during the leaching process correlated with high activity for all the porous Au catalysts. CO oxidation catalyzed by porous Au leached with NaOH and HNO{sub 3} is considered to be dominated by different mechanisms at low (< 320 K) and high (> 370 K) temperatures. Activity in the low-temperature region is mainly attributed to the perimeter interface between residual Al species (AlO{sub x}) and porous Au, whereas activity in the high-temperature region results from a high density of lattice defects such as twins and dislocations, which were evident from diffraction peak broadening and were observed with high-resolution TEM in the porous Au leached with NaOH. It is proposed that atoms located at lattice defects on the surfaces of porous Au are the active sites for catalytic reactions.

• OSTI ID: 22493672
• Journal Information: Journal of Chemical Physics, Vol. 144, Issue 3; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
AQUEOUS SOLUTIONS
CARBON MONOXIDE
CATALYSTS
DISLOCATIONS
FIELD EMISSION
GOLD
HARD X RADIATION
HYDROCHLORIC ACID
INTERFACES
INTERMETALLIC COMPOUNDS
LEACHING
NITRIC ACID
OXIDATION
PHOTOELECTRON SPECTROSCOPY
POROUS MATERIALS
SCANNING ELECTRON MICROSCOPY
SODIUM HYDROXIDES
TEMPERATURE DEPENDENCE
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION