Quantifying Interface-Dependent Active Sites Induced by Strong Metal–Support Interactions on Au/TiO₂ in 2,5-Bis(hydroxymethyl)furan Oxidation

Strong metal–support interactions (SMSI) typically induce the migration of a coverage layer to the metal surface accompanied by electron transfer, forming a unique metal–support interface. This dual modification in geometric and electronic structures reconstructs the active surface, adjusting the activity and stability of the catalyst. However, identifying and quantifying such newly formed interfacial sites remains a challenge. Herein, by varying the reduction temperature to control the TiO2–x coverage on Au nanoparticles, the catalytic activity of Au/TiO2 in 2,5-bis(hydroxymethyl)furan (BHMF) oxidation shows a volcano-shaped trend. Combined thiol titration and poisoning kinetics analysis to quantify the ratio of interfacial to surface sites and normalize it to intrinsic activity, revealing that Au-TiO2–x interfacial sites positively contribute to catalytic performance. This study offers valuable insights into the active sites in heterogeneous catalytic systems with SMSI effects.