Rutile TiO₂ Confined Atomic Palladium Species Boosts C−C Coupling Efficiency in Sonogashira Coupling Reactions

Developing high‐performance Pd‐based catalysts with ultra‐low Pd loading is essential but challenging for the multi‐step Sonogashira coupling reactions. Structure–function relationships for single atom catalysts (SACs) are highly dependent on the coordination environments of active sites on appropriate supports. Herein, a facile strategy consisting of crystal phase engineering and thermal atomization to access a Pd‐based SAC with 0.35 wt% Pd loading (Pd₁/TiO_2‐x) is reported. The resulting material consists of spatially isolated Pd atoms decorated on rutile TiO₂ (a support that is frequently overlooked in catalyst design). The use of this Pd catalyst in the Sonogashira C−C coupling of iodobenzene and phenylacetylene to diphenylacetylene achieves distinguished catalytic efficacy, rendering a high yield of 98% and a turnover frequency (TOF) of 23 809 h⁻¹, which is comparable to similar state‐of‐the‐art catalysts. Mechanistic investigations disclose that this strategy promotes interfacial electron transfer between the metal and support, endowing a unique electronic structure and ensuring electronic metal–support coupling effects in Pd₁/TiO_2‐x. This significantly affects the adsorption/activation of reactants and the desorption of intermediates/products, thereby strongly boosting the coupling efficiency. These findings highlight the great importance of catalyst design for multi‐step coupling reactions.