A unique coordination-driven route for the precise nanoassembly of metal sulfides on metal-organic frameworks

Incorporating different materials, such as metal sulfides, with metal-organic frameworks (MOFs) to develop MOF-based multifunctional composites with enhanced performance is an important area of research. However, the intrinsically high interfacial energy barrier significantly restricts the heterogeneous nucleation and nanoassembly of metal sulfides onto MOFs during the wet chemistry synthesis process. Herein, taking advantage of the natural tailorability of MOFs, the precise and controllable growth of metal sulfide nanoparticles (NPs) (CdS, ZnS, CuS and Ag2S) at the coordinatively unsaturated metal sites (CUSs) of MOFs to form MOF@metal sulfide composites under mild conditions is achieved via a cysteamine-assisted coordination-driven route. During the process, the molecular linker of cysteamine, possessing one amino group for chelating with the CUSs of the MOF and one thiol group as a docking site to anchor metal ions, plays a prominent role in enhancing interfacial interactions between the MOF and metal ions. The subsequent S2- anion exchange process leads to intimate surface-attached nucleation and epitaxial growth of metal sulfide NPs on the surface of the MOF. The as-formed composites exhibit enhanced charge separation and transfer capability, and thus boost photocatalytic performance. This general and simple approach provides a new avenue for the design of MOF-metal sulfide hybrids.