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

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 m/g. 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 (H2/CO) ratio of 1. There was no methane formation for these catalysts under the tested conditions.

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Document Details

Document Type
Technical Report
Publication Date
Nov 04, 2009
Accession Number
ADA509905

Entities

People

  • Anatoly I Frenkel
  • Deryn Chu
  • Ivan C. Lee
  • Karen J. Gaskell
  • Lourdes G. Salamanca-riba
  • Osifo Akhuemonkhan
  • Qi Wang
  • Ranjan K. Pati
  • Sheryl H. Ehrman
  • Sicong Hou

Organizations

  • University of Maryland

Tags

Communities of Interest

  • Energy and Power Technologies
  • Space

DTIC Thesaurus Topics

  • Chemical Synthesis
  • Chemistry
  • Diffraction
  • Electron Energy
  • Electron Microscopes
  • Energy
  • High Resolution
  • Liquids
  • Materials
  • Materials Laboratories
  • Materials Processing
  • Materials Science
  • Molecular Dynamics
  • Nanoparticles
  • Transition Metals
  • Transitions
  • X Rays

Fields of Study

  • Materials science

Readers

  • Materials Science and Engineering.
  • Nanocomposite Materials Science
  • Thin Film Deposition Science.

Technology Areas

  • Microelectronics
  • Microelectronics - Graphene