Different morphologies on Cu–Ce/TiO(2) catalysts for the selective catalytic reduction of NO(x) with NH(3) and DRIFTS study on sol–gel nanoparticles

The copper–cerium binary oxide catalysts supported by titanium dioxide with nanosphere core–shell structures, nanotube (TNT) core–shell structures, impregnation (imp) nanoparticles and sol–gel nanoparticles were prepared for NH(3)-SCR of NO(x) under medium-low temperature conditions. The effect of different morphologies on the Cu–Ce/TiO(2) catalysts was comprehensively studied through physicochemical characterization. The results showed that the sol–gel nanoparticles exhibited 100% NO(x) reduction efficiency in the temperature range of 180–400 °C. Compared with the other catalysts, the sol–gel nanoparticle catalyst had the highest dispersion and lowest crystallinity, indicating that morphology played an important role in the NH(3)-SCR of the catalyst. The in situ DRIFTS study on the sol–gel nanoparticle catalyst shows that cerium could promote Cu(2+) to produce abundant Lewis acid sites, which would significantly increase the adsorption reaction of ammonia on the catalyst surface, thereby promoting the occurrence of the Eley–Rideal (E–R) mechanism. With the Ce–Ti interaction on the atomic scale, the Ce–O–Ti structure enhanced the redox properties at a medium temperature. In addition, cerium oxide enhances the strong interaction between the catalyst matrix and CuO particles. Therefore, the reducibility of the CuO species was enhanced.