Praseodymium doping in ceria-supported palladium nanocatalysts as an effective strategy to minimize the inhibiting effects of water during methane oxidation

Mesoporous Ceria and Ceria‐Praseodymia as High Surface Area Supports for Pd‐based Catalysts with Enhanced Methane Oxidation Activity

“…The results of the deconvolution, in terms of abundance of Ce 3+ and Pr 3+ ions, are reported in Table 2. The amount of reduced Ce ions decreased with the introduction of praseodymium and this finding is in line with previous investigations on materials with similar composition [15,16,43] . The amount of reduced Pr ions is rather similar for the three Pd/Ce90Pr10 samples.…”

“…The latter ones can be ascribed to the reduction of surface and bulk cerium species, respectively. This behavior is not present in this work and this fact is expected from previous studies [16,49] . The reduction of cerium oxide can be severely modified by the presence of palladium.…”

“…As far as the high temperature range is concerned (i. e. 500–900 °C), the dopant addition turned out to be essential to limit the typical loss of activity of Pd‐based materials around 700–800 °C [11,16] . In order to investigate this aspect, two of the high‐surface area materials of this work (Pd/CeO 2 _D e Pd/Ce90Pr10_D) were tested up to 900 °C.…”

“…Although these materials have already been extensively studied, further efforts are needed to limit the loss of activity around 700–800 °C due to the PdO‐Pd transition and the detrimental effects of water [11–14] . In this context, the Pd deposition on Ce−Pr supports has been investigated over the past few years, obtaining materials with a higher catalytic activity with respect to Pd/CeO 2 , a better stability of the PdO species in the high temperature range, and an interesting behavior in the presence of water [15,16] . However, these materials were characterized by very low surface area values, while an increase in this parameter can be expected to considerably improve the catalytic performance of these catalysts [17,18] …”

WOx/ZrOx functionalised periodic mesoporous organosilicas as water-tolerant catalysts for carboxylic acid esterification

“…35,36 Such mechanistic dependencies are not unique to esterication reactions, elevated surface hydrophobicity has been shown to promote methane adsorption pathways (and subsequent conversion) over palladium/ceria-praseodymia catalysts for direct methane oxidation. 37 Increased hydrocarbon affinity of hydrophobic Ag/ Al 2 O 3 catalysts was also benecial in mitigating site-blocking deactivation phenomena in the catalytic reduction of NO x to N 2 . 38 Controlling surface polarity and hydrophobicity is therefore a powerful route to improve the water tolerance of metal oxides, which can be achieved in mesoporous silicas either through organic group functionalisation 17,39 or using periodic mesoporous organosilicas.…”