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Title: Insights into the dominant factors of porous gold for CO oxidation

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.
Authors:
;  [1] ;  [2] ;  [1] ;  [3]
  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)
  3. (NIMS), Tsukuba 305-0047 (Japan)
Publication Date:
OSTI Identifier:
22493672
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 144; Journal Issue: 3; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
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