文摘
Shape-controlled synthesis of multicomponent metal nanocrystals (NCs) bounded by high-index facets (HIFs) is of significant importance in the design and synthesis of highly active catalysts. It is a highly challenging task to design and synthesize ternary alloy NCs with HIFs due to the formidable difficulties in controlling the nucleation/growth kinetics of NCs in the presence of three metal precursors with different reduction potentials. We report herein, for the first time, the preparation of Pt鈥揘i鈥揅u alloy NCs by tuning their shape from crossed, dendritic, concave nanocubic (CNC) to rough octahedral (ROH) NCs through a facile one-pot solvothermal synthesis method. Specifically, the crossed and CNC Pt鈥揘i鈥揅u alloy NCs are bounded by high-index {hk0} facets and ROH with rich lattice defects. The electrocatalytic activities of these Pt鈥揘i鈥揅u alloy NCs toward methanol and formic acid oxidation were tested. It was shown that these Pt鈥揘i鈥揅u alloy NCs exhibited enhanced activity and stability compared to commercial Pt black and Pt/C catalysts as well as previous Pt鈥揘i and Pt CNCs under the same reaction conditions, demonstrating the superior electrocatalytic activity of Pt鈥揘i鈥揅u ternary alloys compared to monometal and binary Pt鈥揘i NCs. Surprisingly, we have found that the Pt鈥揘i鈥揅u ROH NCs have exhibited a higher specific catalytic activity than the crossed and CNC Pt鈥揘i鈥揅u alloy NCs with HIFs. The electronic and structure effects have been extensively discussed to shed light on the excellent electrocatalytic performance of Pt鈥揘i鈥揅u ROH NCs.