How to Remove the Capping Agent from Pd Nanocubes without Destructing Their Surface Structure for the Maximization of Catalytic Activity?

Abstract We report a robust method for effectively removing the chemisorbed Br − ions, a capping agent, from the surface of Pd nanocubes to maximize their catalytic activity. The Br − ions can be removed by simply heating the sample in water, but the desorption of Br − ions will expose the underneath Pd atoms to the O 2 from air for the formation of a relatively thick oxide layer. During potential cycling, the oxide layer evolves into detrimental features such as steps and terraces. By introducing a trace amount of hydrazine into the system, the Br − ions can be removed by heating without forming a thick oxide layer. The as‐cleaned nanocubes show greatly enhanced activity toward formic acid oxidation. This cleaning method can also remove Br − ions from Rh nanocubes and it is expected to work for other combinations of nanocrystals and capping agents.