Gallium: A Universal Promoter Switching CO2 Methanation Catalysts to Produce Methanol


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Date

2025-01-27

Publication Type

Journal Article

ETH Bibliography

yes

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Abstract

Hydrogenation of CO2 to methanol is foreseen as a key step to close the carbon cycle. In this study, we show that introducing Ga into silica-supported nanoparticles based on group 8-9 transition noble metals (M = Ru, Os, Rh, and Ir - MGa@SiO2) switches their reactivity from producing mostly methane (sel. > 97%) to producing methanol (>50% CH3OH/DME sel.) alongside CO as the only byproduct. These silica-supported catalysts, prepared via a surface organometallic chemistry (SOMC) approach, consist of small, alloyed, and narrowly distributed MGa nanoparticles, as evidenced by X-ray absorption spectroscopy (XAS) and CO adsorption studies. Notably, detailed in situ XAS and diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) studies complemented with density functional theory (DFT) calculations indicate that Ga generates stable bulk MGa alloys. The bulk MGa alloys persist during CO2 hydrogenation according to XAS, resulting in suppressed methanation. Meanwhile, a small fraction of surface GaOx and thereby MGa-GaOx interfaces are formed, as evidenced by IR spectroscopy, likely responsible for stabilizing methoxy intermediates and favoring methanol formation.

Publication status

published

Editor

Book title

Journal / series

Volume

5 (1)

Pages / Article No.

217 - 224

Publisher

American Chemical Society

Event

Edition / version

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Geographic location

Date collected

Date created

Subject

CO2 hydrogenation; SOMC; gallium promoter; methanation suppression; methanol synthesis

Organisational unit

Notes

Funding

180544 - NCCR Catalysis (phase I) (SNF)
169134 - Molecular Approach to Heterogeneous Catalysis (SNF)
192050 - Molecular Approach and Understanding in Heterogeneous Catalysis (SNF)

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