The control of the size, composition, and shape of platinum nanocrystals has attracted much attention recently, mostly due to their unique properties and related catalytic functionalities. However, the realization of platinum nanocrystals with controlled exposed facets and dimensionality remains a significant challenge. Herein, we show an efficient synthetic strategy to selectively prepare highly controllable platinum nanocrystals with distinct dimensionalities from onedimensional nanowires to zero-dimensional octahedra. Although the synthesis of platinum nanowires has been reported multiple times, the synthetic approach reported herein is much more novel and robust and ultimately results in high yields of high-quality platinum nanowires. Such dimensionality tuning on {111} facet dominated platinum nanocrystals allows us to firstly investigate the effect of the number of edges/corners on the electrocatalytic properties. Our results show that the synthesized platinum nanocrystals exhibit very interesting dimensionality-dependent electrocatalytic activity towards both the oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR), in which one-dimensional platinum nanowires with minimized edges/corners show enhanced electrocatalytic activities with respect to zero-dimensional platinum octahedra. Our dimensionality tuning also provides Pt nanowires with superior durability for the oxygen reduction reaction with negligible activity decay over the course of 30, 000 potential sweeps. The present work highlights that the {111} facet bound platinum nanowires with minimized edges/corners are indeed promising candidates as electrocatalysts with excellent activity and superior durability.