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.