Synthesis of Convex Hexoctahedral Palladium@Gold Core–Shell Nanocrystals with {431} High-Index Facets with Remarkable Electrochemiluminescence Activities

Convex hexoctahedral nanocrystals have been synthesized through fast growth kinetics and the use of cetyl­pyridinium chloride as a capping agent. Monodisperse convex hexoctahedral Pd@Au core–shell nanocrystals with {431} high-index facets are obtained at high reaction rates by using high concentrations of ascorbic acid in the presence of cetyl­pyridinium chloride. In contrast, octahedral nanocrystals with {111} low-index facets and their {100}-truncated counterparts are formed at low ascorbic acid concentrations. The substitute of cetyl­pyridinium chloride with cetyl­trimethyl­ammonium chloride leads to the generation of concave tris­octahedral Pd@Au core–shell nanocrystals with {331} high-index facets, indicating that cetyl­pyridinium plays an important role in the formation of convex hexoctahedral nanocrystals. The as-prepared convex hexoctahedral Pd@Au core–shell nanocrystals exhibit remarkable catalytic performances toward electro­chemi­luminescence compared with truncated octahedral and concave tris­octahedral Pd@Au core–shell nanocrystals