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In situ trapped high-density single metal atoms within graphene: Iron-containing hybrids as representatives for efficient oxygen reduction
Nano Research ( IF 9.9 ) Pub Date : 2018-03-19 00:00:00 , DOI: 10.1007/s12274-017-1840-8
Daobin Liu , Chuanqiang Wu , Shuangming Chen , Shiqing Ding , Yaofeng Xie , Changda Wang , Tao Wang , Yasir A. Haleem , Zia ur Rehman , Yuan Sang , Qin Liu , Xusheng Zheng , Yu Wang , Binghui Ge , Hangxun Xu , Li Song

Atomically dispersed catalysts have attracted attention in energy conversion applications because their efficiency and chemoselectivity for special catalysis are superior to those of traditional catalysts. However, they have limitations owing to the extremely low metal-loading content on supports, difficulty in the precise control of the metal location and amount as well as low stability at high temperatures. We prepared a highly doped single metal atom hybrid via a single-step thermal pyrolysis of glucose, dicyandiamide, and inorganic metal salts. High-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM) and X-ray absorption fine structure spectroscopy (XAFS) revealed that nitrogen atoms doped into the graphene matrix were pivotal for metal atom stabilization by generating a metal-Nx coordination structure. Due to the strong anchoring effect of the graphene matrix, the metal loading content was over 4 wt.% in the isolated atomic hybrid (the Pt content was as high as 9.26 wt.% in the Pt-doped hybrid). Furthermore, the single iron-doped hybrid (Fe@N-doped graphene) showed a remarkable electrocatalytic performance for the oxygen reduction reaction. The peak power density was ∼199 mW·cm−2 at a current density of 310 mA·cm−2 and superior to that of a commercial Pt/C catalyst when it was used as a cathode catalyst in assembled zinc-air batteries. This work offered a feasible approach to design and fabricate highly doped single metal atoms (SMAs) catalysts for potential energy applications.

中文翻译:

石墨烯中原位捕获的高密度单金属原子:含铁杂化物代表有效的氧还原

原子分散的催化剂在能量转换应用中已引起关注,因为它们对特殊催化的效率和化学选择性优于传统催化剂。但是,由于载体上的金属负载量极低,难以精确控制金属的位置和数量以及在高温下的稳定性低,它们具有局限性。我们通过葡萄糖,双氰胺和无机金属盐的一步热裂解制备了高掺杂的单金属原子杂化物。高角度环形暗场扫描透射电子显微镜(HAADF-STEM)和X射线吸收精细结构光谱(XAFS)显示,掺杂到石墨烯基质中的氮原子通过生成金属-Nx配位结构对于稳定金属原子至关重要。 。由于石墨烯基体的强锚固作用,在孤立的原子杂化物中金属负载量超过4 wt。%(在掺Pt杂化物中Pt含量高达9.26 wt。%)。此外,单一的铁掺杂杂化物(Fe @ N掺杂的石墨烯)对氧还原反应显示出显着的电催化性能。峰值功率密度约为199 mW·cm-2在310毫安的电流密度·厘米-2,并且当它被用来作为在组装锌-空气电池的阴极催化剂优于市售的Pt / C催化剂。这项工作为设计和制造用于潜在能量应用的高掺杂单金属原子(SMAs)催化剂提供了一种可行的方法。
更新日期:2018-03-19
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