Development of Thermal Resistant Three-Way Catalysts

Suppression of Noble Metal Sintering Based on the Support Anchoring Effect and its Application in Automotive Three-Way Catalysis

“…As the thermal durability of cerium oxide is insufficient for automotive catalyst ceria based compound containing some additives such as cerium-zirconium oxide are usually used in practical exhaust catalysts [1][2][3][4]. From XAFS analysis as described in Fig.…”

“…It has been trying many methods to improve catalytic activity after ageing the catalysts; improving noble metal dispersion with high surface area supports, adding some promoters, and improving thermal stability of these supports and promoters, etc. [1][2][3][4][5][6][7]. However, it has not been established a valid method for suppressing noble metals sintering and it eventually has resulted to use lots of noble metal for catalysts to meet the stringent emission restrictions.…”

Noble Metal Sintering Suppression Technology in Three-way Catalyst: Automotive Three-way Catalysts with the Noble Metal Sintering Suppression Technology Based on the Support Anchoring Effect

“…Thermal stabilization of alumina support has been conducted. Addition of rare earth and alkaline earth compounds to alumina in a transition state has prevailed as one of the most useful techniques [6,7]. The thermal stability of ceria-zirconia compound as oxygen storage material has been largely improved by mixing with nano-sized alumina particles as a diffusion barrier [10,11].…”

“…One of the biggest issues for three-way catalysts is the degradation of catalytic activity caused by sintering of noble metals as active sites. Many attempts had been tried to improve catalytic activity after ageing the catalysts, such as enhancing the noble metal dispersion with high surface area supports, adding some promoters, and improving thermal stability of these supports and promoters, etc [1][2][3][4][5][6][7][8][9][10][11]. Thermal stabilization of alumina support has been conducted.…”

Destruction of volatile organic compounds by catalytic oxidation

“…Besides the diminution of the surface area, these "macroscopic movements of the substrate" are accompanied by a decrease in the mechanical strength of the catalyst (Shkrabina et al 1995). At the same time, the metal particles dispersed on alumina can stick together (Miyoshi et al, 1989) or/and can be encapsulated into the carrier (process known as the"earthquake phenomena") (Tucci, 1982). Thus, the metal surface area decreases and the catalytic activity is reduced.…”