Chinese Journal of Catalysis ›› 2013, Vol. 34 ›› Issue (5): 942-948.DOI: 10.1016/S1872-2067(12)60546-4

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Nano-size effect of Au catalyst for electrochemical reduction of oxygen in alkaline electrolyte

ZHANG Gui-Rong, XU Bo-Qing   

  1. Innovative Catalysis Program, Key Lab of Organic Optoelectronics & Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084, China
  • Received:2013-01-11 Revised:2013-05-20 Online:2013-05-06 Published:2013-05-06
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (21033004) and the National Basic Research Program of China (2013CB933103).

Abstract:

Oxygen reduction reaction (ORR) in alkaline electrolyte (0.5 mol/L KOH) was studied on a series of carbon supported Au nanoparticles (NPs) with average sizes ranging from 3 to 14 nm, using the rotating disk electrode methods. Downsizing the Au NPs from 14 to 3 nm resulted in continued enhancement in both the intrinsic and mass-specific activity of Au for ORR but produced no influence on the reaction mechanism or number of transferred electrons per O2-reduction. Careful analyses of the particle shapes of Au NPs with varied sizes by using high-resolution transmission electron microscopy enabled us to estimate the fraction of surface Au atoms at different positions or coordination (energy) state. Correlating the fraction of high energy surface atoms with the Au activity for ORR disclosed the importance of high energy surface atoms in enhancing the intrinsic activity of Au. Fundamental correlation between the Au intrinsic activity for ORR and the experimentally determined surface electronic structure of Au NPs was also established.

Key words: Au nanoparticle, Size effect, Oxygen reduction reaction, Surface electronic structure, Alkaline electrolyte