摘要
The development of highly active and low-cost catalysts for electrochemical reactions is one of the most attractive topics in the renewable energy technology.Herein,the site-specific nitrogen doping of graphdiyne(GDY)including grap-N,sp-N(Ⅰ)and sp-N(Ⅱ)GDY is systematically investigated as metal-free oxygen reduction electrocatalysts via density functional theory(DFT).Our results indicate that the doped nitrogen atom can significantly improve the oxygen(O2)adsorption activity of GDY through activating its neighboring carbon atoms.The free-energy landscape is employed to describe the electrochemical oxygen reduction reaction(ORR)in both O2 dissociation and association mechanisms.It is revealed that the association mechanism can provide higher ORR onset potential than dissociation mechanism on most of the substrates.Especially,sp-N(Ⅱ)GDY exhibits the highest ORR electrocatalytic activity through increasing the theoretical onset potential to 0.76 V.This work provides an atomic-level insight for the electrochemical ORR mechanism on metal-free N-doped GDY.
开发高效、低成本的电化学反应催化剂是可再生能源技术研究的热点之一.本文采用密度泛函理论(DFT)系统地研究了grap-N,sp-N(Ⅰ)和spN(Ⅱ)三种位置的氮掺杂对不含金属的石墨炔(GDY)氧还原电催化剂性能的影响.研究表明,GDY中掺杂的氮原子通过活化其相邻的碳原子,可以显著提高GDY的氧气(O2)吸附活性.采用自由能图描述电化学氧还原反应(ORR)的解离(dissociation)和结合(association)机制.结果表明,在大多数底物上结合机制比解离机制能提供更高的ORR起始电位.其中,sp-N(Ⅱ)掺杂GDY的理论起始电位为0.76 V,表现出最高的ORR电催化活性.本文为不含金属的N掺杂GDY的电化学ORR机理提供了原子水平的理解.
基金
financial supports by the Young Scientists Fund of the National Natural Science Foundation of China (11604249)
the Fok Ying-Tong Education Foundation for Young Teachers in the Higher Education Institutions of China (161008)
the Foundation of the State Key Laboratory of Optical Fiber and Cable Manufacture Technology (SKLD1602)
the State Key Laboratory of Refractors and Metallurgy (G201605), the Fundamental Research Funds for the Central Universities (2019-III-034)
the Research Board of the State Key Laboratory of Silicate Materials for Architectures
financial supports and grants from Xiamen University Malaysia,the Xiamen University Malaysia Research Fund (XMUMRF/2019-C3/ IENG/0013)
