Visible Light Driven Water Splitting in a Molecular Device with Unprecedentedly High Photocurrent Density

A molecular water oxidation catalyst (2) has been synthesized and immobilized together with a molecular photosensitizer (1) on nanostructured TiO2 particles on FTO conducting glass, forming a photoactive anode (TiO2(1+2)). By using the TiO2(1+2) as working electrode in a three-electrode photoelectrochemical cell (PEC), visible light driven water splitting has been successfully demonstrated in a phosphate buffer solution (pH 6.8), with oxygen and hydrogen bubbles evolved respectively from the working electrode and counter electrode. By applying 0.2 V external bias vs NHE, a high photocurrent density of more than 1.7 mA·cm–2 has been achieved. This value is higher than any PEC devices with molecular components reported in literature.