I would like to perform chemisorption of CuO depostied on carbon substrate. I have performed that analysis using H2 as the chemisorption probe. I am getting very less active metal surface area. Kindly suggest me what would be the proper gas to analyze Cu based samples. Also, please let me know the analysis temperature. Thanks in advance.....
As suggested by Dr. Singh, the copper metal dispersion is usually determined using N2O as the probe for the following reaction: Cu(0) + N2O = CuO + N2. The problem you present is how to characterize a supported CuO. Here the problem is complicated by the fact that CuO/support will sometimes be present as a mixture of copper oxidation states. Hydrogen along only weakly adsorbs to metallic Cu, and will react with Cu(I) and Cu(II) at higher temperatures to form water. CO only chemisorbs to Cu(I). If one tries to reduce all of the copper oxide to copper metal, some change in the dispersion is possible during the reduction; thus introducing uncertainty how to relate the N2O measurement to the original dispersion of the supported copper oxide. Some have used a controlled oxidation/reduction of supported copper oxide to determine the reversible oxygen pick up and water elimination. The dispersion is calculated from a consideration of the stoichiometry of the redox reactions.
As suggested by Dr. Singh, the copper metal dispersion is usually determined using N2O as the probe for the following reaction: Cu(0) + N2O = CuO + N2. The problem you present is how to characterize a supported CuO. Here the problem is complicated by the fact that CuO/support will sometimes be present as a mixture of copper oxidation states. Hydrogen along only weakly adsorbs to metallic Cu, and will react with Cu(I) and Cu(II) at higher temperatures to form water. CO only chemisorbs to Cu(I). If one tries to reduce all of the copper oxide to copper metal, some change in the dispersion is possible during the reduction; thus introducing uncertainty how to relate the N2O measurement to the original dispersion of the supported copper oxide. Some have used a controlled oxidation/reduction of supported copper oxide to determine the reversible oxygen pick up and water elimination. The dispersion is calculated from a consideration of the stoichiometry of the redox reactions.
There is an article adjusted, quite old - but it can give you some ideas.
Dear Mark G White, could you be so kind to give a link for the articles about Copper reduction. What do you mean by "higher temperatures to form water"?
- Badges
- Science topic