A new route for visible/near-infrared-light-driven H2 production over titania: Co-sensitization of surface charge transfer complex and zinc phthalocyanine

• Low cost and high efficient vis/NIR-light-driven H2 production catalyst is prepared.
• In situ formation of surface LMCT complex catalyst with high H2 production activity.
• TiO2 co-sensitized with ZnPc derivative (Zn-tri-PcNc) and surface LMCT complex.
• Co-sensitized catalyst has relative high AQY of 0.97% at 700 nm light irradiation.

This work introduces a new strategy for visible/near-infrared (NIR) light responsive H2 production over TiO2 nanoparticles co-sensitized with zinc phthalocyanine derivative (Zn-tri-PcNc) and surface ligand-to-metal charge transfer (LMCT) complex, which is in situ formed on the TiO2 nanoparticles' surfaces by using ascorbic acid (AA). The in situ formed surface LMCT complex (AA-TiO2) exhibits obvious visible-light-responsive photoactivity (126.2 μmol/h) for H2 production with a high apparent quantum yield (AQY) of 16.1% at 420 nm monochromatic light irradiation. Moreover, the co-sensitized TiO2 nanoparticles (Zn-tri-PcNc-TiO2-AA) shows a much higher photoactivity (162.2 μmol/h) for H2 production than the surface LMCT complex, and broader spectral responsive region (400–800 nm) with a relatively high AQY value (0.97%) at 700 nm monochromatic light irradiation. The present result reveals a possible substitute for the conventional Ru(II)-bipyridyl complexes or organic dyes as sensitizer of semiconductors in the field of solar fuel conversion.

A novel panchromatic light responsive photocatalyst, which shows excellent H2 production activity in the range of 400–800 nm, is successfully constructed by co-sensitization of surface charge transfer complex and zinc phthalocyanine.Figure optionsDownload as PowerPoint slide