Shao Zhiyu, Meng Haihong, Sun Jing, Guo Niankun, Xue Hui, Huang Keke, He Feng, Li Fengyu, Wang Qin
College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021, P. R. China.
Physical School of Science and Technology, Inner Mongolia University, Hohhot 010021, China.
ACS Appl Mater Interfaces. 2020 Nov 18;12(46):51846-51853. doi: 10.1021/acsami.0c15870. Epub 2020 Nov 9.
Integration of amorphous structures and anion defects into ultrathin 2D materials has been identified as an effective strategy for boosting the electrocatalytic performance. However, the in-depth understanding of the relationship among the amorphous structure, vacancy defect, and catalytic activity is still obscure. Herein, a facile strategy was proposed to prepare ultrathin and amorphous Mo-FeS nanosheets (NSs) with abundant sulfur defects. Benefited from the ultrathin, amorphous nanostructure, and synergy effect of Mo-doping and sulfur defect, the Mo-FeS NSs manifested excellent electrocatalytic activity toward oxygen evolution reaction (OER) in alkaline medium, as shown by an ultralow overpotential of 210 mV at 10 mA cm, a Tafel slope of 50 mV dec, and retaining such good catalytic stability over 30 h. The efficient catalytic performance for Mo-FeS NSs is superior to the commercial IrO and most reported top-performing electrocatalysts. Density functional theory calculations revealed that the accelerated electron/mass transfer over the oxygen-containing intermediates can be attributed to the amorphous structure and sulfur-rich defects caused by structural reconfiguration. Furthermore, the S vacancies could enhance the activity of its neighboring Fe-active sites, which was also beneficial to their OER kinetics. This work integrated both amorphous structures and sulfur vacancies into ultrathin 2D NSs and further systematically evaluated the OER performance, providing new insights for the design of amorphous-layered electrocatalysts.
将非晶结构和阴离子缺陷整合到超薄二维材料中已被认为是提高电催化性能的有效策略。然而，对非晶结构、空位缺陷和催化活性之间关系的深入理解仍然模糊不清。在此，我们提出了一种简便的策略来制备具有丰富硫缺陷的超薄非晶态Mo-FeS纳米片（NSs）。得益于超薄的非晶纳米结构以及Mo掺杂和硫缺陷的协同效应，Mo-FeS NSs在碱性介质中对析氧反应（OER）表现出优异的电催化活性，在10 mA cm时过电位低至210 mV，塔菲尔斜率为50 mV dec，并在30 h以上保持良好的催化稳定性。Mo-FeS NSs的高效催化性能优于商业IrO₂和大多数报道的高性能电催化剂。密度泛函理论计算表明，含氧中间体上加速的电子/质量转移可归因于结构重构引起的非晶结构和富硫缺陷。此外，S空位可以增强其相邻Fe活性位点的活性，这也有利于它们的OER动力学。这项工作将非晶结构和硫空位整合到超薄二维NSs中，并进一步系统地评估了OER性能，为非晶层状电催化剂的设计提供了新的见解。
