MgO–Al2O3 Mixed Oxides-Supported Co–Mo-Based Catalysts for High-Temperature Water–Gas Shift Reaction

Abstract

MgO-Al 2 O 3 mixed oxides were prepared and used as the support of Co-Mo-based water-gas shift reaction (WGSR) catalysts. X-ray diffraction (XRD) characterization showed that the MgO-Al 2 O 3 mixed oxides support is composed of MgO, c-Al 2 O 3 , and magnesiaalumina spinel. The MgO-Al 2 O 3 mixed oxides-supported Co-Mo-based catalysts exhibited high shift activity at high temperature (360-450°C) and high stability. The addition of potassium enhanced the activities but affected adversely the stabilities of Co-Mo-based catalysts. ESR characterization shows that the Mo 5+ species are not connected with the WGSR activity. Magnesium in the support may be closely related with the formation of formate species intermediate for the WGSR.

Water–gas shift activity of K-promoted (Ni)Mo/γ-Al2O3 systems in sulfur-containing feed

“…Sulfided Mo-based supported systems have been designed as sulfur-resistant WGS catalysts. A major part of the studies are related to the structure and activity of Co-Mo catalysts, both unpromoted [11][12][13][14][15] and promoted by alkaline metals [16][17][18][19][20]. To our knowledge, unpromoted Ni-Mo catalysts [21,22] or that promoted by alkaline metals [23] are so far less investigated.…”

Efficient One-Stage Bio-Oil Upgrading over Sulfided Catalysts

“…85%). 48,49 Consequently, an unequivocal interpretation of the gaseous product composition, particularly of the C1 product distribution, is extremely challenging if not even impossible. Thus, we have limited the following discussion to describing the observed dependencies rather than drawing not fully substantiated conclusions.…”

Sour gas shift process over sulfided Co–Mo–K catalysts supported on carbon material — Support characterization and catalytic activity of catalysts

“…The introduction of other oxide modifiers to Al 2 O 3 changes the character of interactions between the active phase and the support which results in formation of active centers of higher stability on the catalyst surface. For example, addition of magnesium oxide partially neutralizes alumina acidity and stabilizes γ-Al 2 O 3 phase inhibiting its transition to α-Al 2 O 3 [21]. It was confirmed by extensive studies carried out by Liana et al [22] which determined optimal Mg/Al ratio.…”

“…It is also known, that the addition of modifiers into support can be an effective way to improve distribution of active components and finally catalytic properties [21][22][23]. The introduction of other oxide modifiers to Al 2 O 3 changes the character of interactions between the active phase and the support which results in formation of active centers of higher stability on the catalyst surface.…”