(701g) Carbon Monoxide Oxidation on Nitrogen and Copper Doped TiO2

Authors: 
Yi, N., University of New Hampshire
Cao, G., University of New Hampshire
Titanium dioxide (TiO2), is a well-known support for photocatalysis, where it shows its efficiency in the removal of unwanted impurities from water and air, as well as generating chemicals, particularly hydrogen from water splitting [1]. Meanwhile, various TiO2-supported catalysts including Cu-TiO2 have been previously developed for numerous industrial applications [2], such as the water gas shift (WGS) reaction, the selective catalytic reduction of NOx, and carbon monoxide oxidation. Among those diverse catalytic processes, carbon monoxide oxidation is attractive especially for preventing the poisoning of Pt catalysts by CO in proton exchange membrane fuel cell.

We developed one efficient approach to improve the interaction between copper and titania support with the aid of nitrogen addition, and elucidated the important role that copper cluster plays in improved activity and stability in CO oxidation. The nitrogen concentration on the surface was optimized by tuning the initial weight ratio of urea and TiO2 and calcination temperatures. The XPS analysis revealed the maximum nitrogen concentration on the surface was achieved once calcination temperature reached 450 oC. Compared with undoped TiO2, the addition of nitrogen facilitated the copper bound on the surface as well as the increase of actual copper loading. TEM characterization also confirmed that copper formed small clusters on nitrogen modified TiO2. Kinetic studies focused on the measurement of the reaction rate regarding the carbon monoxide oxidation reaction. Three-fold increases were observed over copper modified nitrogen-titania. Stability results from time-on-stream test and start-shutdown also favored the nitrogen modified Cu-TiO2. The enhanced activity and stability could be attributed to nitrogen facilitating the formation of copper clusters on TiO2 surface.

References:

  1. Fujishima, A., Zhang, X.T., Tryk, D. A. Sur.Sci.Rep. 63, 515 (2008).
  2. Bartholomew, C. H., Farrauto, R. J. in “Industrial Catalytic Process” p.67. Wiley-Interscience, New Jersey, 2006. 
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