Abstract
High-performance platinum (Pt)-based catalyst development is crucially important for reducing high overpotential of sluggish oxygen reduction reaction (ORR) at Pt-based electrocatalysts, although the high cost and scarcity in nature of Pt are profoundly hampering the practical use of it in fuel cells. Thus, the enhancing activity of Pt-based electrocatalysts with minimal Pt-loading through alloy, core−shell or composite making has been implemented. This article deals with enhancing electrocatalytic activity on ORR of commercially available platinum/carbon (Pt/C) with graphene sheets through a simple composite making. The Pt/C with graphene sheets composite materials (denoted as Pt/Cx:G10−x) have been characterized by several instrumental measurements. It shows that the Pt nanoparticles (NPs) from the Pt/C have been transferred towards the π-conjugated systems of the graphene sheets with better monolayer dispersion. The optimized Pt/C8:G2 composite has higher specific surface area and better degree of graphitization with better dispersion of NPs. As a result, it shows not only stable electrochemical surface area but also enhanced ORR catalytic activity in respect to the onset potential, mass activity and electron transfer kinetics. As shown by the ORR, the Pt/C8:G2 composite is also better resistive to the alcohol crossover effect and more durable than the Pt/C.
Highlights
The sluggish kinetics of four electron involved electrocatalytic oxygen reduction reaction (ORR)in an acidic environment is a major obstacle for the development of cost effective fuel cells (FCs) [1,2,3,4].The development of catalysts with high activity for the ORR is essential to proton exchange membrane fuel cells (PEMFCs), since the majority of activation losses occur at the cathode and it turns into an interesting research area [1,2,3,4,5,6,7]
NPs were not detached from the and graphene was prepared through a simple composite making
All described results confirmed that the Pt/C8 :G2 composite exhibited stable electrochemical surface area (ECSA) with minimal Pt-loading which resultant from higher specific surface area (SSA) and composite catalyst is much efficient ORR catalyst in terms of better electrocatalysis, stability and fuel aggregation-free dispersion of Pt NPs
Summary
The sluggish kinetics of four electron involved electrocatalytic oxygen reduction reaction (ORR). To prevent the aggregation of graphene, many researchers are trying to design a three-dimensional (3D) structure [32,33] or make composites with carbon materials [34,35,36,37] that could facile the ORR performance as well [34,37] This is due to the synergistic contributions of large surface area and π-electron-rich sp2 -G sheets [37] and the non-precious particulate-like sp3 -carbon [38]. The optimized composite, Pt/C8 :G2 , showed a higher and more stable electrochemical surface area (ECSA) and enhanced ORR catalytic activity in respect to the onset potential, MA and electron transfer kinetics in acid media than that of Pt/C, which result from higher specific surface area (SSA) and better degree of graphitization with better dispersion of Pt NPs. the as-prepared Pt/C8 :G2 composite is demonstrated to be a promising cost effective, highly efficient and stable ORR electrocatalyst
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