Nanoconfinement-Controlled Synthesis of Highly Active, Multinary Nanoplatelet Catalysts from Lamellar Magic-Sized Nanocluster Templates

Magic-sized semiconductor nanoclusters (MSCs) possessing intermediate stability are promising precursors for synthesizing low-dimensional nanostructures that cannot be achieved by direct methods. However, uncontrolled diffusion of MSCs in their colloidal-state poses challenges in utilizing them as precursors and/or templates for the controlled synthesis of nanomaterials. Herein, a nanoconfined diffusion-limited strategy to synthesize large CdSe nanoplatelets through the solid-state transformation of (CdSe)₁₃ MSCs is designed, wherein MSCs serve as both precursors and lamellar bilayer templates. In sharp contrast, in the colloidal-state, these MSCs are grown to CdSe nanoribbons or nanorods. Furthermore, the nanoconfined route is used not only to transform (CdSe)₁₃, Mn²⁺:(CdSe)₁₃, and Mn²⁺:(Cd_1−xZn_xSe)₁₃ MSCs but also to dope Cu⁺, producing Cu⁺:CdSe, Mn²⁺/Cu⁺:CdSe, Mn²⁺/Cu⁺:Cd_1−xZn_xSe nanoplatelets, respectively. The resulting multinary nanoplatelets with controlled compositions exhibit unique optical and magneto-optical properties through characteristic exciton transfer mechanisms. Furthermore, synergistic effects have made quinary Mn²⁺/Cu⁺:Cd_0.5Zn_0.5Se nanoplatelets efficient and reusable catalysts for chemical fixation of CO₂ with epoxide (turnover frequency: ≈200/h) under mild conditions. This nanoconfined synthetic strategy paves the way to synthesize diverse shape-controlled multi-component nanostructures for optoelectronic and other catalytic applications.