Inexpensive water oxidation catalysts are needed to develop photocatalytic solar cells that mimic photosynthesis and produce fuel from sunlight and water. This paper reports the successful attachment of a dinuclear di - oxo manganese water oxidation catalyst [H2O(terpy)Mniii(-O)2 Mniv(terpy)H2O](NO3)3 (1, terpy = 2,2′:6′2″-terpyridine) onto TiO2 nanoparticles (NPs) via direct adsorption, or in situ synthesis. The resulting surface complexes are characterized by EPR and UV-visible spectroscopy, electrochemical measurements and computational modeling. We conclude that the mixed-valence (iii,iv) state of 1 attaches to near-amorphous TiO2 NPs by substituting one of its water ligands by the TiO2 NP, as suggested by low-temperature (7 K) EPR data. In contrast, the analogous attachment onto well-crystallized TiO2 NPs leads to dimerization of 1 forming Mn(iv) tetramers on the TiO2 surface as suggested by EPR spectroscopy and electrochemical studies.
ASJC Scopus subject areas
- Environmental Chemistry
- Renewable Energy, Sustainability and the Environment
- Nuclear Energy and Engineering