Rapid Screening of Bimetallic Electrocatalysts Using Single Nanoparticle Collision Electrochemistry

The pace of nanomaterial discovery for highperformance electrocatalysts could be accelerated by the development of efficient screening methods. However, conventional electrochemical characterization via drop-casting is inherently inaccurate and time-consuming, as such ensemble measurements are serially performed through nanocatalyst synthesis, morphological characterization, and performance testing. Herein, we propose a rapid electrochemical screening method for bimetallic electrocatalysts that combines nanoparticle (NP) preparation and performance testing at the single NP level, thus avoiding any inhomogeneous averaging contribution. We employed single NP collision electrochemistry to realize in situ electrodeposition of a precisely tunable Pt shell onto individual parent NPs, followed by instantaneous electrocatalytic measurement of the newborn bimetallic core-shell NPs. We demonstrated the utility of this approach by screening bimetallic Au-Pt NPs and Ag-Pt NPs, thereby exhibiting promising electrocatalytic activity at optimal atomic ratios for methanol oxidation and oxygen reduction reactions, respectively. This work provides a new insight for the rapid screening of other bimetallic electrocatalysts.