Aqueous-Phase Synthesis of Pt and PGM-Based Nanocrystals with a Controllable Size

Colloidal metal nanocrystals (NCs) have attracted significant attention due to their unique properties. Precise control of their synthesis is crucial for obtaining the desired properties determined by size, shape, and composition, which are essential for many specific applications. Current synthetic methods for producing uniform colloidal nanocrystals often involve the use of organic reagents, which are expensive and toxic and require special disposal procedures. As a more sustainable and cost-effective alternative, water-based synthesis methods have been developed, and control of the nanocrystal properties is important to achieve. In this work, we developed a synthetic method for preparing uniform platinum (Pt) nanocrystals in the aqueous phase with benign reagents. A systematic study of the synthesis parameters revealed that uniform nanocrystals could be formed through a size-focusing behavior using poly(vinylpyrrolidone) (PVP) as a protecting ligand and glucose as a reducing agent. The size of Pt nanocrystals could be tuned from 2.8 to 4.7 nm using a successive seed-mediated approach. Furthermore, this synthesis method could be extended to other platinum-group metals (Pd and Rh) and Pt-based bimetallic systems (Pt/Pd and Pt/Rh), demonstrating the versatility of our proposed synthetic methods and their applicability in catalytic applications.