Chinese Journal of Catalysis ›› 2026, Vol. 89: 402-409.DOI: 10.1016/S1872-2067(26)65131-5

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Spectroscopically probing the cobalt state in TiO2-supported CO2 hydrogenation catalysts derived from tailored materials via atomic layer deposition and surface organometallic chemistry

Xiaoyu Zhoua, Wei Zhoua, James Patersonb, Jamie Southouseb, Alexey Fedorovc, Christoph R. Müllerc, Christophe Copéreta,*()   

  1. aDepartment of Chemistry and Applied Biosciences, ETH Zurich, CH-8093 Zurich, Switzerland
    bBP Technology, Applied Sciences and Technology BP plc, Saltend, Hull, HU12 8DS, United Kingdom
    cDepartment of Mechanical and Process Engineering, ETH Zurich, CH-8092 Zurich, Switzerland
  • Received:2026-01-14 Accepted:2026-04-21 Online:2026-10-18 Published:2026-09-01
  • Contact: *E-mail:ccoperet@inorg.chem.ethz.ch(C. Copéret).

Abstract:

TiO2 is ubiquitous as a support in catalytic applications. However, its highly absorptive nature hampers the use of transmission-based spectroscopic techniques such as X-ray absorption spectroscopy (XAS), limiting in-situ/operando structure-activity studies. Here, we developed a combined atomic layer deposition (ALD) and surface organometallic chemistry (SOMC) approach to synthesize cobalt nanoparticles (NPs) supported on a TiO2 thin film dispersed on SiO2, yielding a spectroscopically accessible Co/TiO2-SiO2 model catalyst. The Co/TiO2-SiO2 exhibits CO₂ methanation activity similarly to Co/TiO2 but in contrast to Co/SiO2, which preferentially catalyzes the reverse water gas shift reaction. In-situ Co K-edge XAS during CO2 hydrogenation conditions demonstrates that cobalt remains metallic, consistent with the observed methanation activity. This study highlights that combining ALD and SOMC provides a versatile platform for constructing TiO2-supported model catalysts and enables their characterization via in situ spectroscopy.

Key words: CO2 hydrogenation, TiO2-supported cobalt, Atomic layer deposition, Surface organometallic chemistry, X-ray absorption spectroscopy