La(5)Ti(2)Cu(0.9)Ag(0.1)S(5)O(7) Modified with a Molecular Ni Catalyst for Photoelectrochemical H(2) Generation

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 TiO(2)‐coated La(5)Ti(2)Cu(0.9)Ag(0.1)S(5)O(7) photocathode for visible light driven H(2) 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 TiO(2) 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.