Morphological transformation of Pt nanocrystals by an electrochemical method in alkaline media and performance of ethanol electrooxidation

Abstract

Controlling the surface structure and shape of platinum group metals (PGMs) is an effective strategy to improve their electrocatalytic performance. Electrochemical methods have demonstrated significant advantages in the preparation of PGM nanocrystals (NCs) with various morphologies. Currently, PGM NCs are mainly prepared in acidic media, while research on the morphological evolution of PGM NCs in strong alkaline media remains limited. Herein, we investigated the morphological transformation of tetrahexahedral Pt NCs (THH Pt NCs) in strongly alkaline media. Trisoctahedral Pt NCs (TOH Pt NCs) and rhombic dodecahedral Pt NCs (RD Pt NCs) were obtained, which are difficult to prepare in acidic media. Furthermore, we investigated the performance of TOH Pt NCs, RD Pt NCs, and octahedral Pt NCs (OH Pt NCs) for ethanol electrooxidation. Among them, OH Pt NCs exhibited the highest peak current density under alkaline conditions, while RD Pt NCs showed the optimal ethanol oxidation activity in acidic medium. These results are consistent with fundamental research on single-crystal planes and provide a bridge for fundamental and applied research. This study provides new insights for the design and preparation of high-performance Pt-based catalysts.