Abstract
Electrocatalysis is the heart of the electrochemical energy conversion, in order to optimize rate, selectivity, energy and stability of certain electrochemical reactions - such as oxygen reduction (ORR), oxygen evolution (OER), and hydrogen evolution (HER) - proper catalysts have to be developed and optimized. Precious noble-metals (e.g. Pt, Ru, Ir, and Pd) supported on carbon nanomaterials (e.g. graphene, carbon nanotubes, and carbon black) have been employed to facilitate the ORR, OER and HER, resulting in high catalytic activities. Nevertheless, these noble-metal based catalysts suffer from high cost, scarcity, poor stability, and detrimental environmental effect. Therefore, to achieve large-scale development at low-cost without drawbacks, it is essential to develop alternative catalytic materials. To address this issue, we propose to design a novel catalytic structure comprised of heteroatoms doped-graphene anchored onto carbon fiber yarns by using simple electrochemical technique, instead of expensive CVD and pyrolysis methods. This unique structure of the material will be binder free and will take advantage of the abundant active sites of doped-graphene network and the support of the carbon fiber yarns will have an opportunity to reduce the overpotential of the reactions by enhancing the interfacial conductivity between the yarns and graphene. Fundamentally, this work is aimed at broadening the current understanding of various essential parameters, such as deposition amount of doped-graphene onto carbon fiber yarns, electron-transfer dynamics, morphology, crystallinity, surface area, as well as defects, which impact the performance of an electrocatalyst. Such parameters are critical in the optimization of catalytic activity of the product. (AU)
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