In particular, the core–shell structure has emerged as a very attractive catalytic component, because unanticipated catalytic properties are often conferred upon the catalyst due to interactions between the shell and the core.Īdzic and co-workers 8, 9 first synthesized core–shell structured nanoparticles with a monolayer of Pt on a Pd core by using an underpotential deposition (UPD) method a monolayer of Cu was deposited on the surface of Pd core particles and this was followed by the galvanic exchange of Cu with a Pt salt solution to form a Pt monolayer. Placing a monolayer or a thin layer (i.e., composed of several atom layers) of Pt on a relatively cheap core-metal nanoparticle can result in high Pt dispersion, large active surface area and high Pt utilization. Recent breakthroughs in approaches to making core–shell structured catalysts fortunately may have shed some light on the route to achieving the commercial application of PEMFCs 5, 6, 7. However, major obstacles to the commercial application of PEMFCs are their use of Pt and their poor durability, both of which result in high cost. PEMFCs are widely recognized as the most promising candidates for the next generation of clean power sources for electrical vehicles and other applications. Low-platinum (Pt) catalysts, realized by either enhancing Pt utilization or reducing Pt loading and thereby decreasing its usage, have been one of the most interesting topics in proton exchange membrane fuel cell (PEMFC) research in the last decade 1, 2, 3, 4. Our findings demonstrate that this novel PED approach is a promising method for preparing high-performance core–shell catalysts for fuel cell applications. The catalyst also shows superior stability: even after 2000 scans, it still retains up to 90% of the peak current. Importantly, we find that the intrinsic activity of Pt in this catalyst is doubled due to the formation of the core–shell structure. We demonstrate that compared with a commercial Pt/C catalyst, this novel catalyst achieves over four times higher mass activity towards the anodic oxidation of methanol and 3.6 times higher mass activity towards the cathodic reduction of oxygen. Here, we report our development of a core–shell structured catalyst, generated by a novel and facile pulse electrochemical deposition (PED) approach. Core–shell structured catalysts, made by placing either a monolayer or a thin layer of a noble metal on relatively cheap core-metal nanoparticles, are fascinating and promising fuel cell catalysts due to their high utilization of noble metals.
0 Comments
Leave a Reply. |