Self‐Regenerating Rh‐ and Pt‐Based Perovskite Catalysts for Automotive‐Emissions Control

Abstract

Automotive catalysts deteriorate as a result of a decrease in the active surface area of the precious metals, this is caused by the growth of grains under the inherent redox environment of exhaust gases at high temperatures of up to 1000 8C. To compensate for this deterioration, conventional catalysts are loaded with an excess amount of precious metals, although this leads to over-consumption and supply problems. Selfregenerating catalysts, which suppress the grain growth of precious metals, have recently been successfully developed and are based on the repeated movement of the precious metals in and out of perovskite oxides between a solid solution and metallic nanoparticles during the natural changes in the redox conditions.[1] Herein, we report for the first time that this self-regenerating function is realizable in Pt and Rh, as well as in Pd.It has been predicted that the demand for precious metals for automotive catalysts will increase, and that these metals will soon be in short supply as a result of the growth in the number of automobiles in China and India and the global

Evolution of the electrochemical interface in high-temperature fuel cells and electrolysers

“…This not only allows for such attractive structural interplay, but also for combining it with other desirable electrode functionality (see Figure 2a) 84,87,89,91,95 , chromite 86,90,94 or chromite-manganite 93,96 perovskite supports. These have been applied to solid oxide fuel cells 86,90,92,94,97 , electrolysis cells 95,98 and for other catalytic process 36,84,85 .…”

Structured Perovskite-Based Catalysts and Their Application as Three-Way Catalytic Converters—A Review

“…On the contrary, LaFe 0.57 Co 0.38 Pd 0.05 O 3 maintains a high Pd dispersion (D = 1-3 nm) and its activity remains unchanged ( Figure 6) [70,74]. Following the discovery of the self-regenerative property of LaFe 0.57 Co 0.38 Pd 0.05 O 3 , several other "intelligent" catalysts based on platinum or rhodium hosted in LaFeO 3 , LaAlO 3 , CaTiO 3 , CaZrO 3 , SrTiO 3 , SrZrO 3 , BaTiO 3 , or BaZrO 3 structure were identified [75]. Each combination of noble metal and host structure is characterized by the proportion of precious metal likely to form a solid solution with the perovskite-type oxide and, therefore, to be involved in the self-regeneration process (Table 1) [75].…”

“…Following the discovery of the self-regenerative property of LaFe 0.57 Co 0.38 Pd 0.05 O 3 , several other "intelligent" catalysts based on platinum or rhodium hosted in LaFeO 3 , LaAlO 3 , CaTiO 3 , CaZrO 3 , SrTiO 3 , SrZrO 3 , BaTiO 3 , or BaZrO 3 structure were identified [75]. Each combination of noble metal and host structure is characterized by the proportion of precious metal likely to form a solid solution with the perovskite-type oxide and, therefore, to be involved in the self-regeneration process (Table 1) [75]. The stronger metal-support interaction of the noble metal with a perovskite-type oxide support, as compared to a conventional alumina support, significantly increases its resistance to thermal sintering, allowing to enhance the catalytic performance while minimizing the noble metal content [76,77].…”

The intelligent catalyst having the self-regenerative function of Pd, Rh and Pt for automotive emissions control

“…The oxidation (O), reduction (OR) and re-oxidation (ORO) treatments of the catalyst were carried out at 800 8C. XAFS measurements were also carried at BL-01B1 and BL-14B1 in SPring-8, to determine the distribution of Rh and Pt in the perovskite crystal structure [22].…”