Surface molecule manipulated Pt/TiO₂catalysts for selective hydrogenation of cinnamaldehyde

Surface states-the electronic states arising as a result of the different bonding environment-are easily contaminated by adsorbed molecules at nanoscale interfaces of metal nanoparticles (NPs), which generally poison the active sites of heterogeneous catalysts. Herein, we use selective hydrogenation of cinnamaldehyde (CAL) on platinum-covered titanium oxide (Pt@P25) as a prototype reaction and show that the competitive exchange of extra introduced species (sodium hydroxide and sodium formate) with spontaneously formed weak bound carbonate and bicarbonate anions at Pt NPs can reconstruct the surface states, which directs the preferred adsorption of the conjugated C=O and C=C double bonds of CAL and, consequently, results in highly efficient synthesis of the unsaturated alcohol cinnamyl alcohol (COL) and the saturated aldehyde hydrocinnamaldehyde (HCAL) with a high selectivity of 94.7% and 97.6%, respectively. Our concept of restructured surface states to tune the chemoselectivity of α, β-unsaturated aldehydes triggered by the selective adsorption of alien molecules may lead to new design principles of heterogeneous catalysts, beyond the conventional dband theory.