Synthesis, Structural Properties and Water Oxidation Activity of Iron (III) Complexes with Salophen Ligands

In this work, FeIII salophen complexes 1-3 were prepared from the reaction of H2L1-3 (H2L1=N,N'-bis(salicylidene)-4-chloro-1,2-phenylenediamine, H2L2=N,N'-bis(salicylidene)-4-bromo-1,2-phenylenediamine, and H2L3=N,N'-bis(salicylene)-4-nitro-1,2-phenylenediamine) with FeCl3.6H2O. The structure of the complexes was investigated by spectroscopic techniques, molar conductivity measurements and elemental analysis. In addition, water oxidation activity of complexes was investigated by different electrochemical methods in alkaline solution. The results showed that the compounds reveal high performance for water oxidation in terms of overpotential and Tafel slope values. FeIII complex 3 displayed the best activity for the reaction with low overpotential of 485 mV at a j of 10 mA cm-2 and a suitable Tafel slope of 216 mV dec-1 among other complexes. This is due to larger electrochemically active surface area of 3, which leads to more active catalytic sites and improved water oxidation activity. Finally, the chronoamperometry test revealed that 3 is a stable and durable electrocatalyst for water oxidation.

Synthesis, Structural Properties and Water Oxidation Activity of Iron (III) Complexes with Salophen Ligands Keywords:

Iron(III) complexes , Salophen-type ligands , Electrocatalysts , Electrochemistry , Water oxidation