Fig. 4: Mechanism investigation.
From: The promotion effect of π-π interactions in Pd NPs catalysed selective hydrogenation
a Reaction orders with respect to H2 and AP on Pd/Py-COF and Pd/Be-COF. b Potential energy profiles for carbonyl hydrogenation of AP with different sequences (O1st C2nd and C1st O2nd). c Arrhenius plots showing apparent activation barriers for Pd/Py-COF and Pd/Be-COF. d FT-IR spectra of AP, Pd/Py-COF and AP absorbed on Pd/Py-COF and Pd/Be-COF. e The interaction energies between COFs and AP/CHO. f TOFs of AP and CHO hydrogenation on Pd/Py-COF and Pd/Be-COF. g Schematic diagram of Pd NPs confined in Py-COF and proposed reaction mechanism of AP hydrogenation on Pd/Py-COF. (Reaction conditions for a: 40 °C, 2 mL of EtOH, H2 pressure varies from 1 to 20 bar, AP concentration varies from ∼7 to ∼28 mg/mL. The TOF values for Arrhenius plots in c were recorded at 30, 40, 50 and 60 °C. Reaction conditions for f: 130 °C, 20 bar of H2, 0.07 mmol of CHO, Pd catalysts 4 mmol%, 2 mL of H2O).
