Innovative Materials with High Stability, High OSC, and Low Light-Off for Low PGM Technology

Heterogeneous environmental catalysis – a gentle art: CeO2–ZrO2 mixed oxides as a case history

“…In summary, there are sparse indications in the literature on the favourable role of the dopant on thermal stability and also on the oxygen storage capacity of the Ce x Zr 1Àx O 2 materials; however, a rationale and a general description of their role is missing [20,21,26,[32][33][34][35][36]. Keeping in mind that ternary and, more often, quaternary CeO 2 -and ZrO 2 -containing materials are nowadays used as TWC promoters, this represents a serious handicap in relation to a basic comprehension of the chemistry of these nanostructured materials.…”

“…This demonstrates that a comparison of the effects of composition on thermal stability is meaningful only when a common texture has been obtained. The importance of the initial texture on the thermal stability was recently demonstrated by researchers from Rhodia: using a bimodal -fractal type of pore distribution, a remarkably high thermal stability could be conferred on these mixed oxides [20,21]. The presence of stable pore network also minimises encapsulation of the precious metal particles upon ageing [20], which is a drawback of Ce x Zr 1Àx O 2 with poor textural stability [22].…”

“…The importance of the initial texture on the thermal stability was recently demonstrated by researchers from Rhodia: using a bimodal -fractal type of pore distribution, a remarkably high thermal stability could be conferred on these mixed oxides [20,21]. The presence of stable pore network also minimises encapsulation of the precious metal particles upon ageing [20], which is a drawback of Ce x Zr 1Àx O 2 with poor textural stability [22]. Clearly, the synthesis conditions strongly affect thermal stability of these mixed oxides, in addition to the effects of dopants [23][24][25][26].…”

Surfactant-assisted Hydrothermal Synthesis of Ceria-Zirconia Nanostructured Materials for Catalytic Applications

“…In the 1990s, many studies were committed to ZrO 2 -CeO 2 oxides, notably to their synthesis and their catalytic properties. [7][8][9] It is generally known that the incorporation of zirconium into the ceria lattice creates a higher concentration of defects thus improving the O 2− mobility; such mobility would explain the outstanding ability to store and release oxygen. [10] This property allows the oxidation of hydrocarbons and CO in rich atmospheres.…”

Rare earths based oxides as alternative materials to Ba in NOx-trap catalysts

“…These materials are known as preferred precious metal carriers [4][5][6] as they prevent for example Pt sintering even after harsh ageing conditions (i.e. 1000°C).…”