Restructuring of titanium oxide overlayers over nickel nanoparticles during catalysis.

Monai, Matteo; Jenkinson, Kellie; Melcherts, Angela E M; Louwen, Jaap N; Irmak, Ece A; Van Aert, Sandra; Altantzis, Thomas; Vogt, Charlotte et al. · Science · 2023

basic_science · Level V

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Abstract

Reducible supports can affect the performance of metal catalysts by the formation of suboxide overlayers upon reduction, a process referred to as the strong metal-support interaction (SMSI). A combination of operando electron microscopy and vibrational spectroscopy revealed that thin TiO<sub>x</sub> overlayers formed on nickel/titanium dioxide catalysts during 400°C reduction were completely removed under carbon dioxide hydrogenation conditions. Conversely, after 600°C reduction, exposure to carbon dioxide hydrogenation reaction conditions led to only partial reexposure of nickel, forming interfacial sites in contact with TiO<sub>x</sub> and favoring carbon-carbon coupling by providing a carbon species reservoir. Our findings challenge the conventional understanding of SMSIs and call for more-detailed operando investigations of nanocatalysts at the single-particle level to revisit static models of structure-activity relationships.