La₅Ti₂Cu_0.9Ag_0.1S₅O₇ Modified with a Molecular Ni Catalyst for Photoelectrochemical H₂ Generation

Abstract

The stable and efficient integration of molecular catalysts into p-type semiconductor materials is a contemporary challenge in photoelectrochemical fuel synthesis. Here, we report the combination of a phosphonated molecular Ni catalyst with a TiO₂ -coated La₅ Ti₂ Cu_0.9 Ag_0.1 S₅ O₇ photocathode for visible light driven H₂ production. This hybrid assembly provides a positive onset potential, large photocurrents, and high Faradaic yield for more than three hours. A decisive feature of the hybrid electrode is the TiO₂ interlayer, which stabilizes the oxysulfide semiconductor and allows for robust attachment of the phosphonated molecular catalyst. This demonstration of an oxysulfide-molecular catalyst photocathode provides a novel platform for integrating molecular catalysts into photocathodes and the large photovoltage of the presented system makes it ideal for pairing with photoanodes.