In silico investigation of ligand-regulated palladium-catalysed formic acid dehydrative decomposition to carbon monoxide under acidic conditions was conducted. Two types of bidentate tertiary phosphine ligands were selected on the basis of previous experimental study. And the promoting effect of para-toluenesulfonic acid (PTSA) was specifically investigated. The pyridyl group implanted in pytbpx ligand is found to mainly contribute on enhancing the activity of palladium catalyst. The PTSA promoter displays specific role for regenerating active species and supressing dehydrogenation during Pd-pytbpx/Pd-dtbpx catalysed dehydration process. CO releasing process catalysed by Pd-dtbpx also facilitated by adding PTSA. According to the mechanism hereby supposed, introducing electron-withdrawing substitution at para-position of pyridyl rings may further improve the dehydrative decomposition activity of Pd-pytbpx.
Fig. S1-4 and Cartesian coordinate of geometry-optimized structures