Pydridoxal (thio) Semicarbazone Ligands and Their Fe(III) Complexes as Potential Electrocatalysts for Hydrogen Evolution Raction

A significant requirement for a future hydrogen economy and easily accessible renewable energy is efficient production of hydrogen from aqueous protons by direct solar energy conversion. The synthesis of a catalyst that can facilitate the reaction of hydrogen evolution (HER) is of paramount importance to achieve this overall objective. This study focuses on catalytical activity of pyridoxal-semi (H-2-PLSC) and pyridoxal-thiosemi (H-2-PLTSC) carbazone molecules and their iron complexes Fe(H-PLTSC)(PLTSC)]center dot 4H(2)O and [Fe(H-2-PLSC)Cl-2 (H2O)]Cl, for electrochemical proton reduction into hydrogen. The free ligands (H-2-PLSC and H-2-PLTSC) were able to electrocatalyze the reduction of proton into hydrogen. Even though, the studied complexes were more catalytically active than the free ligand, this observation provided crucial evidence for the proposed mechanism that involved protonation of the ligand.