Mechanistic Insights on the Semihydrogenation of Alkynes over Different Nanostructured Photocatalysts

A single-molecule microscopy study of the interaction dye-modified alkanes, alkenes, and alkynes with nanostructured catalysts based on TiO2 reveals significant differences in desorption kinetics probe molecules depending chemical nature catalyst. comparison materials decorated palladium (Pd@TiO2) or molybdenum/cobalt (MoCo@TiO2) kinetic that part justify better performance MoCo@TiO2 semihydrogenation reactions. Whereas rate is ∼50% higher for than Pd@TiO2, analysis at bench scale indicate alkene-to-alkane conversion around 10 times faster Pd (k2Pd = 0.02 s–1) MoCo (k2MoCo 0.002 catalysts. This suggests selectivity not solely determined by processes hydrogenation constant (k21) on-surface alkenes to alkanes much Pd@TiO2 MoCo@TiO2. Thus, latter shows greater toward partial reactions compared whose great becomes a disadvantage needed processes.