Development and Simulation of Sulfur-doped Graphene Supported Platinum with Exemplary Stability and Activity Towards Oxygen Reduction (original) (raw)
2014, Advanced Functional Materials
reaction (ORR) occurring at the cathode. Conventional PEMFC systems employ platinum (Pt) based catalysts, which to date have been the only materials capable of facilitating the ORR at rates practical, although still insuffi cient for PEMFC operation. The widespread commercialization and deployment of PEMFCs into advanced sustainable energy infrastructures including the automotive sector is still limited by three primary factors: i) high cost, ii) insuffi cient performance, and iii) low durability. [ 1,2 ] At the root of these limitations lies the aforementioned expensive Pt catalyst materials employed; generally consisting of Pt nanoparticles (≈2-3 nm) uniformly distributed on high surface area carbon black supports (Pt/C). Although signifi cant improvements to state-of-the-art Pt/C catalysts and electrode designs for automobile PEMFCs has been realized in recent years, an immense challenge in achieving the 2017 technical targets set by the United States Department of Energy still remains at the current state of catalyst technology. The targets state that by 2017, the total Pt loading (anode and cathode) must be reduced to below 0.125 mg cm −2 coupled with 5000 h of operational stability under simulated drive cycles. [ 3 ] Specifically, Pt/C is known to degrade under the harsh oxidizing conditions encountered at the PEMFC cathode due to corrosion of the carbon support materials, or by agglomeration and/or dissolution of the platinum nanoparticles resulting from weak interactions with the catalyst supports. [ 4 ] This in turn leads to a sharp loss in available electrochemically active surface areas (ECSA) and by extension fuel cell performance. A common approach to improve catalyst stability and activity has involved the design of non-conventional catalyst supports, including transition metal oxides and nitrides; [ 5-8 ] or alternative carbon supports doped with heteroatoms such as nitrogen to enhance the interaction and synergy between the catalyst particle and its support. [ 9,10 ] It is well understood that the structure and properties of the support materials will directly govern the performance and stability of the catalyst materials. There still however remains a lack of fundamental understanding regarding the exact nature of these particular catalyst-support
Loading Preview
Sorry, preview is currently unavailable. You can download the paper by clicking the button above.