How to Remove the Capping Agent from Pd Nanocubes without Destructing Their Surface Structure for the Maximization of Catalytic Activity?
Yifeng Shi, Zhiheng Lyu, Zhenming Cao, Minghao Xie, Younan Xia
Abstract
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.