Scalable and Cost-Effective Synthesis of Highly Efficient Fe2N-Based Oxygen Reduction Catalyst Derived from Seaweed Biomass
Scalable and Cost-Effective Synthesis of Highly Efficient Fe2N-Based Oxygen Reduction Catalyst Derived from Seaweed Biomass
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DOI：
10.1002/smll.201503305
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发表时间：
2016-03-09
期刊：
影响因子：
13.3
通讯作者：
Yao, Xiangdong
中科院分区：
文献类型：
--
作者：
Liu, Long;Yang, Xianfeng;Yao, Xiangdong
刘龙、杨咸丰、马娜、刘海涛、夏延志、陈成梦、杨东江、*和姚向东*是由于N和Fe的协同作用及其在地壳中的丰度所致。[2,4 - 17]例如，Yin等人利用昂贵的酞菁铁，通过两步水热法合成了氮化铁和n掺杂石墨烯的杂化物，其ORR性能高，但稳定性不高Zhang等制备了铁氮掺杂碳，在明胶-金属骨架中引入硝酸铵气体模板，以增加两步高温煅烧时的比表面积然而，这种处理方法将导致使用昂贵的前驱体进行试验和苛刻的实验，并且使调整催化剂的结构和表面性能变得昂贵一般来说，大多数报道的催化剂都是通过精心设计但复杂的程序合成的。在大规模商业化中的应用是值得怀疑的。此外，目前报道的一些用于ORR的Fe/N/C电催化剂往往不能控制孔隙结构，而孔隙结构决定了活性位点的可达部分和ORR相关物质（H+, e−,o2, H2o）的输运性质，从而导致ORR活性位点暴露有限，输运性质相对较差。显然，目前的方法很难达到美国能源部（DOE）的目标，即在2030年实现更成熟的产量水平，占世界市场的10%在这里，我们描述了一个可扩展的合成Fe 2N/C ORR催化剂通过一个简单的路线。通过与海藻酸盐的四个α-l- gulurate块的配位，将fe3 +阳离子固定在新型“蛋盒”中，制备海藻杂交气凝胶。我们应该再次强调我们的合成方法的优点，它解决了前面提到的所有关键问题：(1)由于海藻前体是可持续的和地球上丰富的，所以合成是一个非常容易、直接和可控的途径。(2)由于该方法非常简单且具有成本效益，因此极有可能将合成扩大到工业水平。(3)令人惊讶的是，Fe - 2n基纳米气凝胶在碱性条件下的ORR活性、稳定性和甲醇耐受性优于Pt。ORR在1 m HClO 4溶液中也具有电催化活性，相对于RHE的起始电位为0.82 V，与Pt/C的起始电位（0.91 V相对于RHE）相当。这归因于纳米凝胶的三维互连分层介孔结构，核/壳结构Fe 2N@碳NPs的优势，以及n掺杂石墨烯的优异导电性。
Long Liu, Xianfeng Yang, Na Ma, Haitao Liu, Yanzhi Xia, Chengmeng Chen, Dongjiang Yang,* and Xiangdong Yao* resulted from the synergistic effect of N and Fe, and its abundance in earth crust.[2, 4–17] For instance, Yin et al. synthesis a hybrid of iron nitride and N-doped graphene, which shows high ORR performance but not quite stable, through two step hydrothermal way and using expensive Fe phthalocyanine.[14] Zhang et al. fabricated iron–nitrogen–doped carbons, of which the gas template of ammonium nitrate is introduced in the gelatin–metal frameworks to increase surface area during two-step high-temperature calcination.[15] However, such treatments will result in trial and harsh experiments using expensive precursors and make it expensive to tailor structure and surface properties of the catalysts.[18] Generally, most of the reported catalysts have been synthesized through well-designed but complicated procedures. The application to serious large-scale commercialization is questionable. In addition, some Fe/N/C electrocatalysts reported for ORR so far frequently fails in controlling the porous structure, which determine the accessible part of active sites and the transport properties of ORR-relevant species (H+, e−, O 2, H2o), thus leading to limited exposure of the ORR active sites and relatively poor transport properties. Apparently, the current approaches are hard to meet the target of US Department of Energy (DOE), that is, a more mature production level at 10% of the world market in 2030 should be accomplished.[1] Here, we describe a scalable synthesis for Fe 2N/C ORR catalysts via a simple route. The coordination with four α-l-guluronate blocks of alginate is used to immobilize Fe 3+ cations into novel “egg-box” for making seaweed hybrid aerogels. We should emphasize again the merits of our synthetic approach, which addressed all the critical issues aforementioned:(1) The synthesis is a really facile, direct, and controllable pathway due to that the seaweed precursor is sustainable and earthabundant.(2) It is highly potential to scale-up the synthesis into an industrial level since the method is very simple and cost-effective.(3) Amazingly, the Fe 2N-based nanoaerogels outperform Pt in the ORR activity, stability and methanol tolerance in alkaline. An electrocatalytic activity for ORR in 1 m HClO 4 solution can also be achieved, with the onset potential of 0.82 V versus RHE, comparable to that of Pt/C (0.91 V vs RHE). This is ascribed to the advantage of the 3D interconnected hierarchical mesoporous structure of nanoaerogels, core/shell structured Fe 2N@ carbon NPs, and the excellent electrical conductivity of N-doped graphene.