Unni Sreekuttan M, Illathvalappil Rajith, Bhange Siddheshwar N, Puthenpediakkal Hasna, Kurungot Sreekumar
Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory , Pune, Maharashtra, India 411008.
Academy of Scientific and Innovative Research (AcSIR), CSIR-National Chemical Laboratory campus , Pune, Maharashtra, India 411008.
ACS Appl Mater Interfaces. 2015 Nov 4;7(43):24256-64. doi: 10.1021/acsami.5b07802. Epub 2015 Oct 20.
Current low-temperature fuel cell research mainly focuses on the development of efficient nonprecious electrocatalysts for the reduction of dioxygen molecule due to the reasons like exorbitant cost and scarcity of the current state-of-the-art Pt-based catalysts. As a potential alternative to such costly electrocatalysts, we report here the preparation of an efficient graphene nanotube based oxygen reduction electrocatalyst which has been derived from single walled nanohorns, comprising a thin layer of graphene nanotubes and encapsulated iron oxide nanoparticles (FeGNT). FeGNT shows a surface area of 750 m(2)/g, which is the highest ever reported among the metal encapsulated nanotubes. Moreover, the graphene protected iron oxide nanoparticles assist the system to attain efficient distribution of Fe-Nx and quaternary nitrogen based active reaction centers, which provides better activity and stability toward the oxygen reduction reaction (ORR) in acidic as well as alkaline conditions. Single cell performance of a proton exchange membrane fuel cell by using FeGNT as the cathode catalyst delivered a maximum power density of 200 mW cm(-2) with Nafion as the proton exchange membrane at 60 °C. The facile synthesis strategy with iron oxide encapsulated graphitic carbon morphology opens up a new horizon of hope toward developing Pt-free fuel cells and metal-air batteries along with its applicability in other energy conversion and storage devices.
由于当前最先进的铂基催化剂成本过高且稀缺等原因，目前低温燃料电池研究主要集中在开发用于还原双氧分子的高效非贵金属电催化剂。作为此类昂贵电催化剂的潜在替代品，我们在此报告了一种基于石墨烯纳米管的高效氧还原电催化剂的制备方法，该催化剂由单壁纳米角衍生而来，包含一层石墨烯纳米管和封装的氧化铁纳米颗粒（FeGNT）。FeGNT的表面积为750 m²/g，这是金属封装纳米管中报道的最高值。此外，石墨烯保护的氧化铁纳米颗粒有助于系统实现Fe-Nx和基于季氮的活性反应中心的有效分布，这在酸性和碱性条件下对氧还原反应（ORR）都提供了更好的活性和稳定性。以FeGNT作为阴极催化剂的质子交换膜燃料电池在60°C下以Nafion作为质子交换膜时，单电池性能提供了200 mW cm⁻²的最大功率密度。具有氧化铁封装石墨碳形态的简便合成策略为开发无铂燃料电池和金属空气电池以及其在其他能量转换和存储设备中的应用开辟了新的希望前景。
