Anode Based on a Molecular Ru Water Oxidation Catalyst Covalently Bonded to Polythiophene

The oxidative electropolymerization of a ruthenium complex containing thiophene groups with the formula [Ru(tda)(pyrS)₂] (where tda is [2,2′:6′,2″-terpyridine]-6,6″-dicarboxylate and pyrS is 4-(2-(thiophen-3-yl)ethyl)pyridine) affords a conductive polymeric material containing an embedded water oxidation catalyst precursor. The method is simple and versatile allowing us to work with different graphitic supports such as glassy carbon, carbon nanotubes, or carbon paper. After activation, the material is shown to perform as a powerful molecular anode for water oxidation with catalyst loadings in the range of 0.31–3.8 nmol·cm^–2, current densities up to 90 mA·cm^–2 at 1.40 V vs NHE, and over 5 × 10⁴ turnover numbers in just 30 min with close to 100% faradic efficiency.