Rhodium Supported on Silica-Stabilized Alumina for Catalytic Decomposition of N2O

Abstract

Silica-stabilized alumina calcined at 1200°C has been used as a support for rhodium catalysts, and tested in catalytic decomposition of N 2 O propellant. Significant enhancement of catalytic performance was obtained on the silica-stabilized catalyst owing to the thermally stable structure favoring the stabilization of Rh 0 species and desorption of oxygen during the decomposition process.

Catalytic abatement of NO and N2O from nitric acid plants: A novel approach using noble metal-modified perovskites

“…However, at high temperature, significant surface reconstructions attributed to partial substitution of Co sites by Pd [13] or iron can occur [14] with the segregation of Co 3 O 4 . Incorporation of Rh has been previously envisaged for moderate-and high-temperature applications [15,16], especially for the decomposition of N 2 O propellant [17,18]. High running temperature leads inevitably to losses of activity mainly due to sintering.…”

“…To compensate deactivation effects, platinum group metals (PGM), especially Rh, which exhibits a much higher activity, can be added through conventional impregnation methods. However, the resulting material can also suffer from deactivation due to crystal transition and Rh volatilization [17]. Alternately, noble metals can be stabilized inside the perovskite structure or through reductive/oxidative pretreatments which can promote a greater stabilization of nano-sized noble metal particles [17].…”

“…However, the resulting material can also suffer from deactivation due to crystal transition and Rh volatilization [17]. Alternately, noble metals can be stabilized inside the perovskite structure or through reductive/oxidative pretreatments which can promote a greater stabilization of nano-sized noble metal particles [17]. The concept of intelligent catalysts was earlier associated with the self-regenerative behavior of noble metal-modified perovskites under three-way conditions with dynamic processes, which stabilize the metal dispersion contrarily to conventional catalysts supported on alumina where noble metals weakly interact and then irreversibly sinter [18][19][20][21][22].…”

Hydroxyapatite-supported rhodium catalysts for N2O decomposition

“…The catalytic activity of rhodium catalysts was found to be significantly influenced by the supports [28,29]. Supports may influence the dispersion of rhodium [30,31], the reducibility of rhodium species [32], and the pathway of reaction [8]. Thus, it is important to find suitable supports for making Rh catalysts, in order to improve the activity in N 2 O decomposition.…”

Microwave-assisted catalytic decomposition of N2O over hexaferrites

“…It is a highly exothermic reaction leading to a temperature rise of over 1300 K. Extensive research has been done to find a catalyst which can decompose this gas at low temperatures and has good thermal stability [2]. In our earlier studies, thermally stable hexaaluminate [3], mullite [4], and SiO 2 or TiO 2 modified Al 2 O 3 [5,6] were employed as catalyst supports for noble metals Ir and Rh and complete conversion of N 2 O below 773 K was achieved even after calcination at 1473 K. In spite of the high activity and excellent thermal stability of these catalysts for high concentration N 2 O decomposition, the high cost of noble metals is still an important limit to their applications.…”