New Layered Chalcogenide-Type Metal Sulfide Materials with Improved Properties for Solar Fuel Production Applications

Novel lamellar chalcogenide materials, named as ITQ-75, are synthesized, focusing on the advancement and alteration of metal (tin and zinc) sulfide-based microstructured materials. These are achieved via hydro(solvo)thermal processes in the presence of N-heterocyclic aromatic structural directing agents. The comprehensive characterization of these materials included fine-tuning their electronic structure through a metal doping strategy and enhancing their accessibility by modifying the synthesis gel composition. This modification involved altering the gel's viscosity or incorporating mesoporogen agents such as saccharide moieties. The most promisingly modified ITQ-75-type materials demonstrated optical band gap values of ≈2.0 eV, falling within the optimal range for efficient solar fuel production processes. Furthermore, the photocatalytic performance of these optimized lamellar chalcogenides is assessed using the water-splitting reaction for hydrogen generation in the gas phase and without any sacrificial reagent. These new noble metal-free materials are revealed to be among the most efficient to date (up to 7 µmol_H2 h cm^{- 2}). The results confirm the potential of these materials as promising photocatalysts for solar fuel production applications.