A dinuclear iron complex as an efficient electrocatalyst for homogeneous water oxidation reaction
Among the current technologies available for producing the environment friendly fuel hydrogen, water splitting reaction have harnessed immense attention. However, such a vital reaction has its own drawbacks in the form of compromised efficiency and turn-over number of water electrolysis. To counteract this drawback, the development of efficient electrocatalyst for the OER is highly expedient. In this present work the electrocatalytic activity of a newly synthesized dinuclear oxo-bridged iron complex [(FeLCl)2O](FeCl4)2] (L=(2-(pyrridin-2-yl)oxazolidi-ne-4,4-diyl) 1 is unveiled. The electrocatalytic activity towards water oxidation reaction has been determined in organic medium with added NaOH. Experimental results show that catalysts are highly stable and molecular oxygen is produced via electrochemical water oxidation with appreciable turnover number (408) coupled with high Faradaic efficiency (>78.6%). Mechanistic investigation revealed that the replacement of chlorides from the complex 1 by hydroxide ions helps in the O–O bond formation during the process of water oxidation, which represents the most crucial step for the oxidation of water to molecular oxygen and this was further substantiated by ESI-MS measurements and UV-VIS studies. To explain such a typical mechanism, DFT calculations were performed. Furthermore, to prove the exclusive role of the cationic part of complex 1, we have synthesized another control complex with a different counter anion [(FeLCl)2O]Cl2 2 and subjected it to electrocatalytic water oxidation reaction. From the results, it was found that control complex 2 has the same efficacy as that of complex 1.