Oxidative coupling of methane over Ba-doped Y2O3 catalyst—Similarity with active site for direct decomposition of NO

Promoting Effect of Cerium Oxide on the Catalytic Performance of Yttrium Oxide for Oxidative Coupling of Methane

“…On the other hand, the BET surface area of CeO 2 /Y 2 O 3 (HT) was lower than those of other samples, although the crystallite size of Y 2 O 3 was evaluated to be small. This conflict might be ascribed to the formation of aggregated Y 2 O 3 crystallites with less-porous structure via hydrothermal process (Haneda et al, 2018). …”

“…Recently, we have investigated that similarity of catalytically active sites for oxidative coupling of methane (OCM) and NO decomposition, and found that the catalysts showing the activity for the latter reaction are also active for the former reaction (Haneda et al, 2018). We also reported that the addition of small amount of CeO 2 into Ba/Y 2 O 3 causes a significant increase in the NO decomposition activity (Doi et al, 2015), suggesting the possibility that CeO 2 behaves as effective promoter for the OCM reaction.…”

Effect of B Site Substitution on the Catalytic Activity of La‐Based Perovskite for Oxidative Coupling of Methane

“…[9][10][11][12] Alkali, alkaline earth, and rare earth have also been reported to be effective elements in OCM reaction. [10,[13][14][15][16] Recently, Nguyen et al [17] investigated high-throughput screening of OCM catalyst focusing on a synergetic combination of MnÀNaÀW-Si, and constructed a catalyst dataset that covers a parametric space of materials and process conditions. They also investigated to optimize the reaction conditions in the OCM reaction over Mn-Na 2 WO 4 /SiO 2 using machine learning.…”

“…[23][24][25][26][27][28][29] Recently, we have investigated the similarity of catalytically active sites for the OCM and NO decomposition reactions, and found that the catalysts showing the activity for the latter reaction are also active for the former reaction. [15] Perovskites are also well-known catalysts showing the activity for NO decomposition. [30][31][32] For example, the activity of LaBO 3 (B: transition metal) for the NO decomposition is strongly affected by the B site cation substituted.…”

A+1Nb5+O3 (A = Li, Na, K) Perovskites with Different Fine Structures for Oxidative Coupling of Methane: Tracing the Crystalline Phase Effect on the Surface Active Sites

“…Over the past decades, quite a lot of catalysts have been studied, particularly including Mn/Na 2 WO 4 /SiO 2 , − Li/MgO, − rare earth oxides, − and perovskites. − Studies have substantiated that ABO 3 perovskites with an alkaline earth or rare earth metal A-site can often stand high temperatures and have potential applications for OCM. , Furthermore, the presence of A-site alkaline earth or rare earth metals can also provide surface basicity for ABO 3 compounds to stabilize the surface active oxygen anions such as O 2 – , O 2 2– , and O – , − which are important for an efficient OCM catalyst. On the other hand, by combining with different B-sites, the B–O bond strength could be tuned, which can influence the reducibility of the lattice O 2– and its surface vacancy concentration. , Through partially replacing the A- and B-sites with heterovalent cations of an ABO 3 perovskite, the surface basicity and O 2– vacancy concentration can be further tailored, which can extend to the surface and facilitate the generation of those active sites needed by the OCM reaction. , …”