Size-dependent strong metal-support interaction modulation of Pt/CoFe2O4 catalysts

Supported metal catalysts are the backbone of heterogeneous catalysis, playing a crucial role in the modern chemical industry. Metal-support interactions (MSIs) are known important in determining the catalytic performance of supported metal catalysts. This is particularly true for single-atom catalysts (SACs) and pseudo-single-atom catalysts (pseudo-SACs), where all metal atoms are dispersed on, and interact directly with the support. Consequently, the MSI of SACs and pseudo-SACs are theoretically more sensitive to modulation compared to that of traditional nanoparticle catalysts. In this work, we experimentally demonstrated this hypothesis by an observed size-dependent MSI modulation. We fabricated CoFe 2 O 4 supported Pt pseudo-SACs and nanoparticle catalysts, followed by a straightforward water treatment process. It was found that the covalent strong metal-support interaction (CMSI) in pseudo-SACs can be weakened, leading to a significant activity improvement in methane combustion reaction. This finding aligns with our recent observation of CoFe 2 O 4 supported Pt SACs. By contrast, the MSI in Pt nanoparticle catalyst was barely affected by the water treatment, giving rise to almost unchanged catalytic performance. This work highlights the critical role of metal size in determining the MSI modulation, offering a novel strategy for tuning the catalytic performance of SACs and pseudo-SACs by fine-tuning their MSIs.