Metal‐Support Interaction Boosts the Photocatalytic Performance of Pd/TiO ₂ for Acetylene Semi‐Hydrogenation: Modulating the H ^* Reaction Behavior and Ethylene Desorption

Photocatalytic acetylene (C₂H₂) semi-hydrogenation reaction is an environmentally friendly process for ethylene (C₂H₄) production. However, all attempts to enhance the C₂H₄ yield have faced kinetic limitations. Electronic metal-support interaction (EMSI) is an effective approach to enhance kinetic constants by regulating the adsorption and desorption capabilities of intermediates and reactive species, promoting the reaction in the forward direction. Herein, Pd/TiO₂ catalysts are constructed by a hydrothermal-calculation method, forming the EMSI effect between Pd and TiO₂. Spectroscopy characterizations and theoretical calculations demonstrate that EMSI promotes the photo-generated charge carriers from TiO₂ to Pd. The control of the local electron density on Pd nanoparticles directly influenced the Gibbs free energy of the H^* reaction and the desorption energy of ^*C₂H₄. This ultimately enhances the consumption and adsorption kinetics of H^*, while simultaneously suppressing H^* desorption and facilitating the desorption of ^*C₂H₄. Consequently, it modulates the preferential order between H₂ evolution and the C₂H₂ semi-hydrogenation, expediting the production of C₂H₄. Therefore, the Pd/TiO₂ achieves 99.7% C₂H₂ conversion, 77.3% C₂H₄ selectivity, and TON_C2H4 = 5960 within 3 h. This work provides a reference and guidance for the subsequent construction of efficient photocatalytic C₂H₂ semi-hydrogenation catalysts.