Electrocatalytic water oxidation by a macrocyclic Cu(ii) complex in neutral phosphate buffer

Abstract

A single-site copper complex, [Cu(TMC)(H₂O)](NO₃)₂ (1, TMC = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane), was found to be the most active copper-based catalyst towards electrocatalytic water oxidation in neutral aqueous solution. Complex 1 leads to a cathodic shift of approximately 200 mV in potential to reach a current density of 1 mA cm⁻² in comparison with that of the previously reported dinuclear copper complex under the same conditions. Upon immobilization of complex 1 on carbon cloth, it shows greatly improved activity than other copper-based WOCs including CuO_x and Cu²⁺.