The influence of molar ratios of Ce/Zr on the selective catalytic reduction of NO x with NH3 over Fe2O3-WO3/Ce x Zr1−x O2 (0 ≤ x ≤ 1) monolith catalyst

Effect of the calcination temperature of cerium–zirconium mixed oxides on the structure and catalytic performance of WO3/CeZrO2 monolithic catalyst for selective catalytic reduction of NOx with NH3

“…10,11 Our previous works showed that the Fe-W/Ce 0.68 Zr 0.32 O 2 with Ce/Zr (molar ratio) of 68 : 32 displayed the best NH 3 -SCR performance, compared to other Fe-W/Ce x Zr 1Àx O 2 with different Ce/ Zr. 12,13 In the above studies, it has been found that the NH 3 -SCR activity of WO 3 /CeZrO 2 catalyst was obviously affected by the calcination temperature of the carrier; however, the optimum calcination temperature of cerium-zirconium mixed oxides and the effects of the calcination temperature on the NH 3 -SCR performance of catalysts have not been investigated to our knowledge, which should play a key role in the practical application of the serial catalysts.…”

“…11, peak 1 was ascribed to the reduction of the surface active oxygen from CZ mixed oxides; peak 2 could be attributed to the reduction of the lattice oxygen from the bulk metal oxides, i.e., non-active lattice oxygen. 12,39 Obviously, the calcination temperature of the carrier modied the redox properties of W/CZ-T catalysts. In Fig.…”

Synthesis of Sulfur-Resistant TiO2-CeO2 Composite and Its Catalytic Performance in the Oxidation of a Soluble Organic Fraction from Diesel Exhaust

“…For the TiO 2 catalyst, the surface adsorbed oxygen ratio is about 38%, and the addition of CeO 2 obviously increases the surface adsorbed oxygen ratio, where the value of TiO 2 -CeO 2 is about 42%. Usually, surface adsorbed oxygen is more reactive than lattice oxygen due to its higher mobility [45,46], and our previous work also confirms that the adsorbed oxygen is more active than the lattice oxygen in the catalytic SOF oxidation reaction [40]. Thus, the addition of CeO 2 in TiO 2 enhances the amounts of surface adsorbed oxygen of TiO 2 -CeO 2 , which can be responsible for the improved catalytic activity of SOF oxidation.…”

“…For the TiO 2 -CeO 2 , the reduction peak at 300-700 • C can be ascribed to the reduction of TiO 2 and surface oxygen of CeO 2 ; interestingly, the reduction peak of bulk oxygen of CeO 2 after 700 • C is poorly identified, which indicates that the TiO 2 -CeO 2 catalyst exhibits lots of surface oxygen, and this result is consistent with XPS result. Consequently, the prepared TiO 2 -CeO 2 catalyst with lots of surface oxygen species presents superior catalytic activity, due to the surface oxygen is highly reactive [45,46].…”

Environmental catalysis: a solution for the removal of atmospheric pollutants

“…The authors also observed that the doping of alkali metals leads to a decrease in the desorbed ammonia amount and the destabilization of acid sites, and such deactivation is related to a decrease in the concentration of chemisorbed oxygen. Chen's group [2] studied the influence of the Ce/Zr molar ratio on the SCR of NO x with NH 3 over the Fe 2 O 3 -WO 3 / Ce x Zr 1-x O 2 monolith catalyst, and claimed that there was a close relationship between the NH 3 -SCR catalytic activity and the Ce/Zr molar ratio. Among all the catalysts, the Fe 2 O 3 -WO 3 /Ce 0.68 Zr 0.32 O 2 catalyst showed the best performance (over 90 % NO x , with a N 2 selectivity of more than 99 %, could be removed at 200-500°C and 30,000 h -1 ), and the catalyst was even resistant to moisture and sulfur dioxide.…”