(192o) Role of C3N4 and Pd in Selective Hydrogenation of Phenol

C₃N₄ is regarded as an ideal supporter for the selective hydrogenation from phenol to cyclohexanone with high selectivity and conversion. However, the investigations on the mechanism are absent. By using the DFT method, we investigate the adsorption, tautomerization and hydrogenation during the selective hydrogenation of phenol on C₃N₄and Pd@C₃N₄. In this progress, phenol first reacts with H to form 1-cyclohexen-1-ol, followed with the tautomerization (0.36 eV and 0.31 eV) to produce cyclohexanone. Once phenol is transferred to cyclohexanone, cyclohexanone prefers desorb (0.33 eV and 0.31 eV) from the surface of substrate rather than hydrogenation (1.24 eV and 0.95 eV) and the existence of Pd also make sense in preventing the further hydrogenation. Density of states of designed structures reveal that Pd affects the properties of C₃N₄ by changes the structures, and it can make sense to the N in six-fold cavities nearby to influence the adsorption of adsorbate. This study provides the progress of hydrogenation for phenol on the Pd@ C₃N₄, and the interactions between N in C₃N₄ and H in the hydroxyl prevent the further hydrogenation, which provides a new perspective on the design of substrates for selective hydrogenation of phenol.