Inherent mass transfer engineering of a Co, N co-doped carbon material towards oxygen reduction reaction
Inherent mass transfer engineering of a Co, N co-doped carbon material towards oxygen reduction reaction
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Co、N共掺杂碳材料对氧还原反应的固有传质工程
DOI：
10.1016/j.jechem.2020.10.028
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发表时间：
2021-07
影响因子：
13.1
通讯作者：
Rui Cao
中科院分区：
文献类型：
--
作者：
Yanzhi Wang;Bin Wang;Haitao Yuan;Zuozhong Liang;Zhehao Huang;Yuye Zhou;Wei Zhang;Haoquan Zheng;Rui Cao
目前关注的小分子电催化过程中的材料设计诱导的传质过程是由外部强制对流通常通过电极旋转，演示催化剂的内在活性的辅助。值得注意的是，在实际的电池配置中，在电极微环境周围不存在强制对流。因此，建立有效的策略，在调整固有的传质过程中，一个没有外部强制对流的援助，也是非常重要的，但很少报道，阻碍进一步的进展。在此，通过设计动力学研究和可控构建均匀的Co，N共掺杂碳材料（粒径范围从10 nm到2 μm），严格建立了尺寸诱导的固有传质策略。该催化剂通过热解沸石咪唑酯骨架（ZIF）67@ZIF-8合成，其中包裹的壳层避免了明显的金属聚集，并且还有助于在碳化后形成丰富的多孔环境。颗粒尺寸对多孔碳催化剂的传质过程有很大的影响。在700 nm左右的颗粒尺寸被揭示是最有利的固有的质量传递过程中的探测范围内，揭示了没有电极旋转和无限的旋转速度获得的塔菲尔斜率的最小差异。后者是通过在Kouteckand-Levich图中将转速外推到无穷大来实现的，通过该方法可以完全消除外部传质限制。由于固有的传质过程，粒径约为700 nm的催化剂在三电极系统和锌-空气电池中均表现出令人印象深刻的ORR活性。这一工作不仅为小分子电催化的传质过程调控提供了新的思路，更重要的是为动力学研究和新型能源材料的定向设计提供了新的思路。
Current concerns on material-design induced mass transfer processes during small molecule electrocatalysis are on the ones assisted by external forced convection generally via electrode rotating, demonstrating the intrinsic activity of catalysts. Of note is that, in practical battery configurations, there is no the forced convection around electrode micro-environments. Therefore, the establishment of effective strategies in tuning the inherent mass transfer process, the one with no assistance by external forced convection, is also greatly significant, but rarely reported, retarding further advances. Herein, a size-induced inherent mass-transfer strategy is scrupulously established through designed kinetic investigations and also controllable construction of uniform Co, N co-doped carbon materials with a wide range of tunable particle sizes from 10 nm to 2 μm. The catalysts are synthesized by a pyrolysis of zeolitic imidazolate framework (ZIF) 67@ ZIF-8, in which the wrapped shell layer avoids evident metal aggregations, and also contributes to rich porous environments after carbonizations. It is unclosed that particle size has a considerable effect on inherent mass transfer processes, even for the porous carbon catalysts. A particle size at around 700 nm is revealed to be most favorable for the inherent mass transfer process within the probed range, revealed by the smallest difference of Tafel slopes obtained with no electrode rotation and with infinite rotation speed. The latter is achieved via extrapolating rotation speeds to infinity in the Koutecký-Levich plots, by which the external mass transfer limitation can be completely eliminated. Contributed by the great inherent mass transfer process, the catalyst with a particle size of around 700 nm exhibits an impressive ORR activity in both three-electrode systems and zinc-air batteries. This work not only establishes a novel strategy in tuning inherent mass transfer process for small molecule electrocatalysis, more importantly, it provides a new dimension in kinetic investigations and oriented design of advanced energy materials.
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影响因子：
4.9
作者：
Gelun Xu;Haitao Lei;Guojun Zhou;Chaochao Zhang;Lisi Xie;Wei Zhang;Rui Cao
通讯作者：
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影响因子：
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影响因子：
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影响因子：
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作者：
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通讯作者：
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影响因子：
13.1
作者：
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通讯作者：
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