Active sites adjustable phosphorus promoted CeO2/TiO2 catalysts for selective catalytic reduction of NOx by NH3

Highly-efficient CeO 2 -TiO 2 -based catalyst is an attractive alternative to traditional V 2 O 5 -based catalysts for selective catalytic reduction of NO x by NH 3 (NH 3 -SCR). Herein, we construct an efficient and stable P-doped CeO 2 /TiO 2 ( y CeTi-P x ) catalyst by dispersing CeO 2 on strongly acidic and highly stable mesoporous P-doped TiO 2 (Ti-P x ). The characteristic structure of Ti-P x causes highly dispersed CeO 2 , strong active component-support interaction, and abundant surface active oxygen and acid sites on CeTi-P catalyst. Therefore, y CeTi-P x catalyst exhibits much higher catalytic activity than y CeTi catalyst at temperature of 200–450 °C. The y CeTi-P x catalysts show high activity in the presence of H 2 O and strong resistance to H 2 O + SO 2 at medium-high temperature, implying that they have great industrial application prospects. Different P/Ti ratio and CeO 2 loading content were investigated. Excessive P doping can block the Ce 4+ /Ce 3+ redox couple, and suppress redox sites on y CeTi-P x catalyst. Additionally, increasing CeO 2 content can reduce the NH 3 capacity of y CeTi-P x catalyst. By controlling the P/Ti ratio and CeO 2 loading content, surface acid sites and redox sites on y CeTi-P x catalyst can be balanced to obtain the best catalytic activity. This work demonstrates a feasible method in adjusting acid sites and redox sites on CeTi catalyst, which ultimately contributes to the new design of CeO 2 -TiO 2 -based catalyst.