Accession Number:

ADA509905

Title:

Flame Synthesis of Nanosized Cu-Ce-O, Ni-Ce-O, and Fe-Ce-O Catalysts for the Water-Gas Shift (WGS) Reaction

Descriptive Note:

Journal article

Corporate Author:

MARYLAND UNIV COLLEGE PARK

Report Date:

2009-11-04

Pagination or Media Count:

13.0

Abstract:

A flame synthesis method has been used to prepare nanosized, high-surface-area Cu-Ce-O, Ni-Ce-O, and Fe-Ce-O catalysts from aqueous solutions of metal acetate precursors. The particles were formed by vaporization of the precursors followed by reaction and then gas to particle conversion. The specific surface areas of the synthesized powders ranged from 127 to 163 sq mg. High-resolution transmission electron microscope imaging showed that the particle diameters for the ceria materials are in the range of 3-10 nm, and a thin layer of amorphous material was observed on the surface of the particles. The presence and surface enrichment of the transition-metal oxides CuO, NiO, and Fe2O3 on the ceria particles were detected using X-ray photoelectron spectroscopy. Electron energy-loss spectroscopic studies suggest the formation of a core-shell structure in the as-prepared particles. Extended X-ray absorption fine structure studies suggest that the dopants in all M-Ce-O systems are almost isostructural with their oxide counterparts, indicating the doping materials form separate oxide phases CuO, Fe2O3, NiO within the host matrix CeO2. Etching results confirm that most of the transition-metal oxides are present on the surface of CeO2, easily dissolved by nitric acid. The performance of the flame-synthesized catalysts was examined toward water-gas shift WGS activity for fuel processing applications. The WGS activity of metal ceria catalysts decreases in the order Cu-Ce-O Ni-Ce-O Fe-Ce-O CeO2 with a feed mixture having a hydrogen to carbon monoxide H2CO ratio of 1. There was no methane formation for these catalysts under the tested conditions.

Subject Categories:

  • Inorganic Chemistry
  • Physical Chemistry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE