Photocatalytic hydrogen evolution from FeMoS-based biomimetic chalcogels

The naturally abundant elements used to catalyze photochemical processes in biology have inspired many research efforts into artificial analogues capable of proton reduction or water oxidation under solar illumination. Most biomimetic systems are isolated molecular units, lacking the protective encapsulation afforded by a protein's tertiary structure. As such, advances in biomimetic catalysis must also be driven by the controlled integration of molecular catalysts into larger superstructures. Here, we present porous chalcogenide framework materials that contain biomimetic catalyst groups immobilized in a chalcogenide network. The chalcogels are formed via metathesis reaction between the clusters [Mo ₂Fe ₆S ₈(SPh) ₃Cl ₆] ^3- and [Sn ₂S ₆] ^4- in solution, yielding an extended, porous framework structure with strong optical absorption, high surface area (up to 150 m ²/g), and excellent aqueous stability. Using [Ru(bpy) ₃] ²⁺ as the light-harvesting antenna, the chalcogels are capable of photocatalytically producing hydrogen from mixed aqueous solutions and are stable under constant illumination over a period of at least 3 weeks. We also present improved hydrogen yields in the context of the energy landscape of the chalcogels.