Well-dispersed high-loading pt nanoparticles supported by shell-core nanostructured carbon for methanol electrooxidation.
Well-dispersed high-loading pt nanoparticles supported by shell-core nanostructured carbon for methanol electrooxidation.
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DOI：
10.1021/la7029278
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发表时间：
2008-02
期刊：
影响因子：
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通讯作者：
Gang Wu;Deyu Li;Changsong Dai;Dianlong Wang;Ning Li
中科院分区：
文献类型：
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作者：
Gang Wu;Deyu Li;Changsong Dai;Dianlong Wang;Ning Li
将原位聚合苯胺的杂化材料与炭黑共炭化，制备了以氮掺杂石墨层为壳、炭黑粒子为核的壳-核结构纳米碳材料。在N掺杂的碳层中，氮原子取代石墨烯结构的边缘和内部的碳原子以分别形成吡啶N和季N结构。结果，碳结构变得更加紧凑，在石墨烯堆叠中显示出弯曲和无序。与未掺杂的碳相比，N掺杂的碳被证明是一种合适的载体材料，以合成高负载量的Pt催化剂（高达60重量%），具有更均匀的尺寸分布和更强的金属-载体相互作用，由于其高的电化学可及表面积，丰富的无序和缺陷，和高的电子密度。此外，氮掺杂的石墨壳层的高结晶度以及电解质/电极界面处的低电荷转移电阻证明了在N掺杂的碳材料上更快的电荷转移速率。可以发现氮掺杂对提高Pt催化剂的CO耐受性的有益作用。相应地，在由N掺杂的碳支撑的高负载量Pt催化剂上实现了甲醇氧化的改善的性能。基于质量活性（Pt利用率）和本征活性（电荷转移速率），广泛讨论了增强的催化性能。因此，N掺杂的碳层比未掺杂的碳层具有许多优点，并将成为燃料电池电催化剂的一种有趣的支撑碳材料。
Shell-core nanostructured carbon materials with a nitrogen-doped graphitic layer as a shell and pristine carbon black particle as a core were synthesized by carbonizing the hybrid materials containing in situ polymerized aniline onto carbon black. In an N-doped carbon layer, the nitrogen atoms substitute carbon atoms at the edge and interior of the graphene structure to form pyridinic N and quaternary N structures, respectively. As a result, the carbon structure becomes more compact, showing curvatures and disorder in the graphene stacking. In comparison with nondoped carbon, the N-doped one was proved to be a suitable supporting material to synthesize high-loading Pt catalysts (up to 60 wt %) with a more uniform size distribution and stronger metal-support interactions due to its high electrochemically accessible surface area, richness of disorder and defects, and high electron density. Moreover, the more rapid charge-transfer rates over the N-doped carbon material are evidenced by the high crystallinity of the graphitic shell layer with nitrogen doping as well as the low charge-transfer resistance at the electrolyte/electrode interface. Beneficial roles of nitrogen doping can be found to enhance the CO tolerance of Pt catalysts. Accordingly, an improved performance in methanol oxidation was achieved on a high-loading Pt catalyst supported by N-doped carbon. The enhanced catalytic properties were extensively discussed based on mass activity (Pt utilization) and intrinsic activity (charge-transfer rate). Therefore, N-doped carbon layers present many advantages over nondoped ones and would emerge as an interesting supporting carbon material for fuel cell electrocatalysts.