Researcher identify active sites enabling direct syngas conversion to light olefins

Zinc chromite (ZnCrO _x ) oxides coupled with zeolites (OXZEO) have shown great promise as the catalyst for the direct conversion of syngas into light olefins. However, identifying the specific active sites for this reaction remains elusive due to the structural complexity of the ZnCrO _x composite oxides.

Recently, a research team led by Prof. BAO Xinhe and Prof. FU Qiang from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences revealed that monodispersed ZnO _x species, anchored on ZnCr ₂ O ₄ spinel surface, are the key active sites for syngas conversion to light olefins. This work was published in Nature Communications .

Researchers demonstrated that ZnO particles, when physically mixed with ZnCr ₂ O ₄ spinel particles and treated in a syngas atmosphere, undergo a reduction-evaporation-anchoring process. This led to the formation of monodispersed ZnO _x species, uniformly distributed up to a loading of 16.0 wt%, on the spinel surface (denoted as ZnCr ₂ O ₄ @ZnO _x ).

A linear correlation between CO conversion and surface ZnO loading confirmed that the ZnO _x overlayer is the active sites, which can efficiently activate both H ₂ and CO. When combined with SAPO-34 zeolite, the ZnCr ₂ O ₄ @ZnO _x catalyst achieved high catalytic performance with 64% CO conversion and 75% light olefins selectivity among total hydrocarbons.

Moreover, the ZnO _x overlayer remained stably anchored on the ZnCr ₂ O ₄ spinel, which inhibits Zn loss during the reaction and maintains high stability over 100 hours. This highlights a significant interface confinement effect between the spinel surface and ZnO _x overlayer, which stabilizes the active sites and boosts catalytic performance.

"Our study provides a clear understanding of how interfacial confinement enhances catalytic activity, and provides a new approach for identifying active sites on supported catalyst surfaces," said Prof. FU.

Nature Communications

10.1038/s41467-025-58951-8

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