Influence of the support on rhodium speciation and catalytic activity of rhodium-based catalysts for total oxidation of methane

Abstract

The role of the support in Rh-based catalysts for total oxidation of CH4 was investigated using both amorphous SiO2 and γ-Al2O3 as well as ZSM-5 and SSZ-13 zeolites with varying...

Recent Advances in Complete Methane Oxidation using Zeolite‐Supported Metal Nanoparticle Catalysts

“…[14,27,28] Concerning the Si/Al of the zeolite, there are some discrepancies in the literature. Some researchers suggest that the acidic sites related to Al in the zeolite accelerate sintering, [27,29,37] whereas others suggest they prevent sintering. [13,14,[57][58][59] The arguments for accelerated sintering generally refer to the increased mobility of palladium oxide on zeolites with a low Si/Al value (i. e. a zeolite with a high Al content), while the arguments for increased stability refer to stronger metal-support interactions.…”

“…In four recent publications, [32,33,37,106] Zhang et al published their work on Rh-based zeolite catalysts for methane oxidation. These exhibited a remarkable tolerance towards SO 2 poisoning, maintaining significant activity after exposure to close-to-realistic conditions.…”

“…Although ion-exchanged Pd sites possess some activity, several studies showed that nanoparticles are more active for complete methane oxidation. [18,37,73] As long as the solvated metal precursor is small enough to enter the microporous framework, ion-exchange is a simple and effective method to achieve well-dispersed inside the zeolite. After calcination, the metal nanoparticles are typically a little larger than the micropores.…”

“…Several studies have shown that hydrophobic zeolites with high Si/Al suffer less from deactivation by water [18,27,28,84] . Additionally, the high Si/Al zeolites typically undergo the fast and reversible kind of water deactivation that results from molecular adsorption instead of forming more stable hydroxyl groups [18,37] . Although several groups have focused on highly silicious zeolites with Si/Al>300, recent results suggest that the optimal Si/Al value is, perhaps surprisingly, around 40 [18,28,37] .…”

“…Zhang et al [37] . investigated the influence of the support and rhodium speciation on total methane oxidation in the presence of water and SO 2 .…”