Adsorption and dehydrogenation of formic acid, hydrazine and isopropanol have been investigated using periodic density functional theory (DFT). All the intermediates and transition states have been optimized and the preferred reaction pathways have been found. The adsorption energies for the most stable mode of formic acid, hydrazine and isopropanol are 38.6 kJ/mol, 63.9 kJ/mol and 46.1 kJ/mol, respectively. The dehydrogenation mechanisms of formic acid, hydrazine and isopropanol on Pd(111) surface are proposed and calculated. According to the calculation results, dehydrogenation of formate is more favorable than those of other molecules/groups, and that can be an explanation for the high reactivity of formats in Pd catalyzed transfer hydrogenation.