| Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2016) | |
| Nanomaterials | Monday Sessions |
| Session NM-MoE |
| Session: | Nanocatalysis |
| Presenter: | Vojislav Stamenkovic, Argonne National Laboratory, USA |
| Correspondent: | Click to Email |
Electrocatalysis is a subclass of heterogeneous catalysis that is aimed towards increase of the electrochemical reaction rates that are taking place at the surfaces. Real-world electrocatalysts are usually based on precious metals in the form of nanoparticles due to their high surface-to-volume ratio, which enables better utilization of employed materials. Ability to tailor nanostructure of an electrocatalyst is critical in order to tune their electrocatalytic properties. Over the last decade, that has mainly been achieved through implementation of fundamental studies performed on well-defined extended surfaces with distinct single crystalline and polycrystalline structures. Based on these studies, it has been demonstrated that performance of an electrocatalyst could be significantly changed through the control of size, composition, morphology and architecture of employed nanomaterials. This presentation will outline the most important in development of an efficient electrocatalyst: 1) electrochemical properties of well-defined surfaces, 2) synthesis and characterization of different electrocatalysts, and 3) correlation between physical properties (size, shape, composition and morphology) and electrochemical behavior (activity and durability). In addition, a novel research platform in the development of functional nanomaterials for energy conversion and storage applications such as fuel cells electrolyzers and batteries will also be presented.
Besides activity, our results have demonstrated that durability of an electrocatalyst can also be tailored by manipulating the catalyst structure. For instance, in order to address this issue a core-shell electrocatalyst where an Au core was coated by a multilayered MPt3 shell was developed. Such core-shell Au/MPt3 electrocatalysts showed negligible activity loss after 60,000 cycles between 0.6 – 1.1 V (vs. RHE). In the most recent example, an entire gold core was replaced by Ni core which was coated by gold and then encapsulated by Pt-bimetallic shell, creating a core-interlayer-shell structure with unique electrochemical properties. In addition, a highly functional hollow type multimetallic structures will be discussed as efficient electrocatalysts for oxygen reduction, hydrogen oxidation and evolution reactions.
Common ground for all systems relies on distinguished approach that includes collection of fundamental knowledge from well-defined highly crystalline systems and connects them to the real world nanomaterials.
References:
[1] Stamenkovic et al. Science 315 (2007) 493.
[2] Stamenkovic et al. Nature Mat. 6 (2007) 241.
[3] Chen et al. Science 343 (2014) 1339.
[4] Kang et al. Nano Letters 14(2014) 6361.