Introduction -- Controllable Synthesis of Water-soluble Pt-Ni Alloys and the Study of their Catalytic Properties -- The Study of a Strategy for Desigining a Concave Pt-Ni Alloy through Controlled Chemical Synthesis -- The Discovery of Nano Defect Effects and the Design of Trimetallic Pt-Ni@M Core-shell Catalysts -- The Synthesis Strategy of Au Modified Pt-Ni Trimetal Nanoframe Structure.

This thesis focuses on the controlled synthesis of Pt–Ni bimetallic nanoparticles and the study of their catalytic properties. It discusses in detail the nucleation mechanism and the growth process of bimetallic systems, which is vital for a deeper understanding of the design of bimetallic catalysts. The author presents four pioneering studies: (1) syntheses of water-soluble octahedral, truncated octahedral, and cubic Pt–Ni nanocrystals and the study of their structure-activity relationship in model hydrogenation reactions; (2) a strategy for designing a concave Pt–Ni alloy using controllable chemical etching; (3) defect-dominated shape recovery of nanocrystals, which is a new synthesis strategy for trimetallic catalysts; (4) a sophisticated construction of Au islands on Pt−Ni, which is an ideal trimetallic nanoframe catalyst. This thesis inspires researchers working in materials, catalysis as well as other interdisciplinary areas. .