Catalytic Water Oxidation by a Ru^II Half Sandwich Complex

Abstract

Water splitting is an emerging domain in the sustainable energy system. In this study a half‐sandwich [Ru(η6‐benzene)(hdm)]BF4 [Ru‐hdm] complex (hdm=hydroxydi(pyridine‐2‐yl)methanolate) has been synthesized and characterized through various spectroscopic techniques. The complex [Ru‐hdm] has been employed to investigate the activity towards electrochemical and chemical water oxidation. Efficient generation of O2 through chemical and electrochemical water oxidation (98 % Faradaic efficiency) in deionized water was observed. The formation of insoluble particles of [RuVI=O] and [RuIV=O] species in the reaction mixture and a coating over the surface of the silicone rubber septum has been noticed. The kinetics of chemical water oxidation reveals the 1st order dependency on CAN and catalyst concentration.

Electrocatalytic water oxidation by heteroleptic ruthenium complexes of 2,6-bis(benzimidazolyl)pyridine Scaffold: a mechanistic investigation

“…The E (Ru III/II ) of fully protonated species remain pH insensitive up to pH 5, 4.5, and 3.8 for 1 , 2 , and 3 , respectively. 21 Therefore, the p K a value of [Ru III (L)(H 2 L 1 /L 2 /L 3 )(OH 2 )] 2+ was determined to be 5, 4.5, and 3.8 for 1 , 2 , and 3 , respectively, which are comparable to those of other reported “Ru III –OH 2 ” species. 22–25 On raising the pH, two different deprotonations of the coordinated ligands are supported by the slopes ∼−118 mV and ∼−59 mV corresponding to the 1e − /2H + and 1e − /1H + proton-coupled electron transfer (PCET) processes for bis-benzimidazolyl pyridine and water, respectively.…”

Water Oxidation by a Neoteric Dinuclear Mn(II) Electrocatalyst in Aqueous Medium

“…Using the equation 5, the surface coverage value was determined. [51] (5) where, i p = peak current, # = scan rate, A = surface area of the working electrode, Γ* = surface coverage of adsorbed species, n = no. of electrons, F = Faraday constant, R = universal gas constant, T = temperature.…”

“…It is inferred that due to the electron transport from the electrode surface by the absorbed species on its surface, mass transfer exceeds charge transfer. Using the equation 5, the surface coverage value was determined [51] …”