Size-dependent metal-support interactions in Co/CeO₂-Y₂O₃ catalysts for enhanced methane dry reforming.

Metal-support interactions (MSI) significantly influence the effectiveness of heterogeneous catalysts. Specific sites at the metal support interface can exhibit high reactivity, prompting increasing interest in optimizing not only the properties of metal particles but also the metal-support interface. Nevertheless, a precise modulation of MSI strength for optimal metal dispersion and size remains a significant challenge. Here, we demonstrate that tuning the particle size of the support by varying calcination temperature can effectively modulate the interaction between Co and CeO₂-Y₂O₃(CY), thereby greatly enhancing the dry reforming of methane (DRM). A combination of X-ray diffraction, H₂-TPR, X-ray photoelectron spectroscopy, and transmission electron microscopy reveals that cobalt nanoparticles, stabilized on CY supports with an intermediate particle size of ∼75 nm, exhibit superior strength and enhanced DRM activity due to improved MSI after reduction at 800 °C. For catalysts with optimal MSI, we demonstrate that facile formation of oxygen vacancies is pivotal for the high DRM activity.