Support effect of MoO_xC_y catalyst in the reverse water gas shift reaction

Abstract

Converting CO₂ into CO via reverse water gas shift (RWGS) reaction is a key step for carbon recycling. Molybdenum trioxide (MoO₃) is a promising precatalyst due to its high activity and near‑unity CO selectivity, yet the role of support properties remains unclear. To address this, a series of MoO₃‑based catalysts supported on MgO, γ‑Al₂O₃, SiO₂, TiO₂, ZrO₂, and CeO₂ were prepared. Systematic characterizations show that MoO₃ undergoes in situ carburization to Mo₂C, and the extent of carburization correlates positively with catalytic activity. The formation of active Mo₂C is governed by the metal oxide‑support interaction (MOSI): strong MOSI between MoO₃ and basic supports (MgO, CeO₂) promotes stable solid solutions that suppress carburization, whereas acidic and amphoteric supports preserve MoO₃ crystallites, enabling efficient carburization and high RWGS performance. Among all catalysts, MoO_xC_y/SiO₂ exhibits the weakest MOSI, the highest surface Mo₂C concentration, and thus superior mass‑specific activity. The ionic potential of the support serves as a descriptor for MOSI strength, while the specific surface area introduces a certain deviation for amphoteric supports (γ‑Al₂O₃, TiO₂, ZrO₂). This work provides clear support selection criteria and a theoretical foundation for rational design of high‑performance Mo‑based RWGS catalysts.

Keywords

CO₂ hydrogenation / syngas platform / molybdenum oxide / molybdenum carbide / metal oxide-support interaction

RIGHTS & PERMISSIONS

Higher Education Press 2026

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