Lanthanum modified Fe-ZSM-5 zeolites for selective methane oxidation with H₂O₂

Abstract

Lanthanum modified Fe-ZSM-5 catalyst can both increase selective methane oxidation performance and decrease H2O2 consumption.

Selective Oxidation of Methane to Methanol via In Situ H2O2 Synthesis

“…The use of the aluminosilicate ZSM-5 within methane oxidation has received considerable attention, while such studies have typically focused on biomimetic oxidation, utilizing Fe and/or Cu species incorporated into the zeolite framework in conjunction with preformed H 2 O 2 . − Additionally, there has been growing attention placed on the use of ZSM-5 as a support for active metal species for both the direct synthesis of H 2 O 2 − and in situ oxidation of methane to methanol . Recently Jin et al reported that enhanced rates of methane oxidation via in situ H 2 O 2 synthesis can be achieved through the introduction of a hydrophobic organo-silane layer onto the external surface of a AuPd@ZSM-5 catalyst, with the improved reactivity attributed to the increased localized concentrations of reagents (H 2 and O 2 ), and the confinement of the subsequently synthesized H 2 O 2 and CH 4 in close proximity to active sites …”

Impact of solvent sulfolane in enhancing methanol selectivity during methane partial oxidation on Fe-ZSM5 catalyst with H2O2 as an oxidant

“…3 Subsequent extensive investigations of LPO of methane have shown that product formation on ZSM-5-based catalysts is affected by various factors, such as the methane inlet pressure, 4–6 oxidant concentration, 4–6 the solvent used, 4 reaction time, 4,5,7–9 temperature of the reaction, 4,10 catalyst amount, 4,6 metal loading 3,7–9,11,12 and acidity/hydrophobic nature of the catalyst. 12–15…”

“…Similarly, lanthanum modification in the Fe-ZSM-5 catalyst suppressed the H 2 O 2 dissociation and enhanced the formation of liquid oxygenates. 12 This indicates the need for controlled dissociation of H 2 O 2 at the active sites for the selective formation of the desired products.…”

“…Hutchings and co-workers first reported the direct liquid phase oxidation (LPO) of methane to methanol using Fe/ZSM-5 catalyst (Si/Al of 30) with water as the solvent and H 2 O 2 as the oxidant, and reported 12% selectivity to methanol with 0.7% methane conversion. 3 Subsequent extensive investigations of LPO of methane have shown that product formation on ZSM-5-based catalysts is affected by various factors, such as the methane inlet pressure, 4–6 oxidant concentration, 4–6 the solvent used, 4 reaction time, 4,5,7–9 temperature of the reaction, 4,10 catalyst amount, 4,6 metal loading 3,7–9,11,12 and acidity/hydrophobic nature of the catalyst. 12–15…”

Insights into Fe Species Structure‐Performance Relationship for Direct Methane Conversion toward Oxygenates over Fe‐MOR Catalysts

“…[21][22][23][24] An aqueous route using H 2 O 2 as environmentally benign oxidant has been thoroughly studied for decades. Hutchings and co-workers have made great contributions in aqueous route using H 2 O 2 as an oxidant at a low temperature on many kinds of heterogeneous substances catalysts, such as Fe-ZSM-5, [25,26] LaFe-ZSM-5, [27] AuPd/TiO 2 , [28,29] AuPdCu/TiO 2 , [30] and AuPd colloid. [31] Recently, Bao and co-workers found that graphene-confined single Fe atoms can directly convert methane into C1 oxygenates at 25 °C with a selectivity of 94 %.…”