TiO₂ Nanotube-Supported Cu as the Catalyst for Selective NO Reduction with NH₃

Abstract

Catalyst supports composed of titanate nanotubes were prepared from hydrothermal treatment on TiO₂ nanoparticles in NaOH followed by HCl washing. The nanotubes exhibited well–defined TiO₂ anatase phase after calcination at 400 °C. The nanotube aggregates and other commercially available TiO₂ nanoparticles, all with surface areas >300 m²/g, were impregnated with Cu and examined in selective catalytic reduction of NO with NH₃. In catalyst preparation, the nanotubes were found to be more thermally stable than nanoparticles, withstanding agglomeration at elevated temperatures. The Cu species supported on the nanotubes showed a higher catalytic activity than those supported on the nanoparticles. Analysis with temperature programmed reduction, X–ray photoelectron spectroscopy, and NO adsorption reflected that the layeredtitanate feature of the tube wall was advantageous for even distribution of the Cu species, thus leading to the high–catalytic activity of the tubular Cu/TiO₂ catalyst.