Visualizing the Spatial Heterogeneity of Electron Transfer on a Metallic Nanoplate Prism.

The involvement between electron transfer (ET) and catalytic reaction at the electrocatalyst surface makes the electrochemical process challenging to understand and control. Even ET process, a primary step, is still ambiguous because it is unclear how the ET process is related to the nanostructured electrocatalyst. Herein, locally enhanced ET current dominated by mass transport effect at corner and edge sites bounded by {111} facets on single Au triangular nanoplates was clearly imaged. After decoupling mass transport effect, the ET rate constant of corner sites was measured to be about 2-fold that of basal {111} plane. Further, we demonstrated that spatial heterogeneity of local inner potential differences of Au nanoplates/solution interfaces plays a key role in the ET process, supported by the linear correlation between the logarithm of rate constants and the potential differences of different sites. These results provide direct images for heterogeneous ET, which helps to understand and control the nanoscopic electrochemical process and electrode design.