Modulating the Coordinatively Unsaturated Mo Species through Oxide-Support Interaction for Enhanced Reverse Water-Gas...

Area of Science:

• Heterogeneous catalysis
• Materials science
• Surface chemistry

Background:

• Coordinatively unsaturated metal species are crucial for oxide-based catalysts.
• Tuning their surface density and stability is challenging due to uncontrolled reduction.

Purpose of the Study:

• To investigate how host oxides influence coordinatively unsaturated Mo species formation and stability.
• To correlate these species with reverse water-gas shift (RWGS) activity.

Main Methods:

• Deposition of MoO₃ onto various oxide supports (m-ZrO₂, a-TiO₂, CeO₂, γ-Al₂O₃, SiO₂) using dry combustion.
• Characterization of catalytic properties, focusing on RWGS reaction.

Main Results:

• Strong oxide-support interactions on m-ZrO₂ and a-TiO₂ lowered reduction temperature, creating stable, high-surface-content coordinatively unsaturated MoO_2-x species.
• MoO₃/m-ZrO₂ and MoO₃/a-TiO₂ exhibited significantly higher CO₂ reaction rates (21 and 14 times, respectively) compared to unsupported MoO₃.
• These catalysts demonstrated excellent stability over 60 hours of reaction.

Conclusions:

• Oxide-support interactions are key to controlling the formation and stability of active Mo species.
• This strategy effectively enhances catalytic performance for the RWGS reaction.
• The findings offer a method for optimizing metal oxide catalysts via interface engineering.